Letter and Word Perception, Volume 4: Orthographic structure and visual processing in reading (Advances in Psychology)

LETTER AND WORD PERCEPTION ADVANCES IN PSYCHOLOGY 4 Editors G . E. STELMACH P. A. VROON NORTH-HOLLAND PUBLISHING C...

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LETTER AND WORD PERCEPTION

ADVANCES

IN PSYCHOLOGY 4 Editors

G . E. STELMACH P. A. VROON

NORTH-HOLLAND PUBLISHING COMPANY AMSTERDAM * NEW YORK * OXFORD

LETTER AND WORD PERCEPTION Orthographic Structure and VisualProcessing in Reading

Dominic W. MASSARO Glen A. TAYLOR Richard L. VENEZKY James E. JASTRZEMBSKI and

Peter A. LUCAS Wisconsin Research and Development Center for Individualized Schooling Universityof Wisconsin

1980

NORTH-HOLLAND PUBLISHING COMPANY AMSTERDAM * NEW YORK * OXFORD

Copyright 1980 -The Board of Regentsof the University of Wisconsin System Copyright is claimed until 1990. Thereafter all portionsof this work covered by this copyright will be in the public domain. Thiswork was developed under agrant from the National Institute of Education, Department of Health, Education, and Welfare. However, the content does not necessarily reflect the position or policy of that Agency, and no official endorsement of these materials should be inferred.

ISBN: 0 444 85493 2

Publishers:

NORTH-HOLLAND PUBLISHING COMPANY AMSTERDAMoNEW YORK. OXFORD Sole distributors for the U.S.A. and Canada: ELSEVIER NORTH-HOLLAND, INC. 5 2 VANDERBILT AVENUE, NEW YORK, N.Y. 10017

Library of Congress Cataloging in Publieation Data

Main entry under title:

Letter and vord perception. (Advances in psychology ; 4) Includes bibliopaphical references and indexes. 1. Reading. 2. Word recognition. 3. English langupee--Alphabet. 4. Reading, Psychology of. I. M688az.0, Dominic W. 11. Series: Advauces in psychology (Amsterdam) 4. LBlO#O.L47 428.4 80-14350

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Preface

...

t o c o m p l e t e l y a n a l y z e w h a t w e d o when w e r e a d would a l m o s t b e t h e acme of a psychologist's achievements, f o r i t would b e t o d e s c r i b e v e r y many o f t h e m o s t i n t r i c a t e w o r k i n g s o f t h e human m i n d , a s w e l l a s t o u n r a v e l t h e t a n g l e d s t o r y of t h e most remarkable s p e c i f i c performance t h a t c i v i l i z a t i o n has learned i n a l l its history. T h e s e w o r d s a r e no l e s s a p p r o p r i a t e t o d a y t h a n t h e y were when Edmund Burke Huey confronted the challenge of understanding reading i n 1 9 0 8 . And a l t h o u g h m o s t l i t e r a t e s o c i e t i e s d e v o t e v a l u a b l e f i n a n c i a l and human r e s o u r c e s t o u n d e r s t a n d i n g r e a d i n g , i t o f t e n seems a s i f w e a r e n o n e a r e r t o It achieving t h i s goal. However, some p r o g r e s s i s a p p a r e n t . is g e n e r a l l y a g r e e d t h a t r e a d i n g i n v o l v e s t h e u t i l i z a t i o n o f a along with the a c t i v e v a s t range of performance s k i l l s a p p l i c a t i o n o f t h e knowledge r e s o u r c e s o f t h e r e a d e r . The g o a l f o r t h e r e s e a r c h e r , i s t o d e s c r i b e e a c h o f t h e s k i l l s an d t o e v a l u a t e how k n o w l e d g e c o n t r i b u t e s t o t h e s k i l l e d p e r f o r m a n c e . Our r e s e a r c h i n v e s t i g a t e s how k n o w l ed g e o f t h e o r t h o g r a p h y ( r u l e s of spelling) i s a c t i v e l y e n g a g e d i n l e t t e r and word As m i g h t be expected, our perception of s k i l l e d readers. r e s e a r c h e n t e r p r i s e had i t s s h a r e o f b o t h s u b s t a n t i v e a d v a n c e s i n our understanding of b a s i c psychological p r o c e s s e s an d distracting glances a t some of t h e mind's bewildering inconsistencies. Our g o a l i n t h i s m o n o g r ap h i s t o c o m m u n i c a t e b o t h t h e p r o g r e s s a n d some o f t h e d i s t r a c t i o n t h a t we

vi i

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experienced. Because o f t h e d e t a i l e d p r e s e n t a t i o n s o f v a r i o u s d e s c r i p t i o n s of orthographic s t r u c t u r e , t h e extended s e r i e s of e x p e r i m e n t a l s t u d i e s , and t h e f i n e - g r a i n e d a n a l y s e s o f t h e c o n t r i b u t i o n o f many d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e , p i e c e m e a l p u b l i c a t i o n s o f t h i s r e s e a r c h e f f o r t would h a v e b e e n inappropriate. T h i s monograph p r o v i d e s t h e c h a l l e n g e o f n o t o n l y communicating a p r o t r a c t e d r e s e a r c h e n t e r p r i s e b u t a l s o a n i l l u m i n a t i n g and i n t e r n a l l y - c o n s i s t e n t a c c o u n t o f how r e a d e r s u t i l i z e knowledge o f o r t h o g r a p h i c s t r u c t u r e i n l e t t e r and word p e r c e p t i o n . The s u c c e s s o f t h i s work w i l l b e e v a l u a t e d by t h e r e s e a r c h e r , and m u s t s t a n d t h e t e s t o f i t s a p p l i c a b i l i t y t o reading i n s t r u c t ion. G i v e n t h e r e l a t i v e l y l a r g e number o f new e x p e r i m e n t a l s t u d i e s t o be reported, w e decided t o omit t h e unimportant d e t a i l s o f t h e method, p r o c e d u r e , and r e s u l t s i n t h e a c t u a l However, s i n c e d i s c u s s i o n of t h e experiments i n Chapter 4 . t h i s i n f o r m a t i o n i s s t i l l o f i n t e r e s t t o many p o t e n t i a l r e a d e r s and r e s e a r c h e r s , i t h a s b e e n p l a c e d i n a p p e n d i c e s a t t h e end o f Chapter 4 . Each e x p e r i m e n t a l s t u d y i s numbered i n C h a p t e r 4 and i t s a p p e n d i x is g i v e n t h e same number. By p l a c i n g unnecessary d e t a i l s i n a p p e n d i c e s , i t is e a s i e r t o m a i n t a i n t h e l o g i c a l c o n t i n u i t y i n t h e p r e s e n t a t i o n of t h e e x p e r i m e n t a l s t u d i e s . When n e c e s s a r y , t h e r e a d e r c a n a l w a y s t u r n d i r e c t l y t o t h e r e l e v a n t appendix f o r a d d i t i o n a l i n f o r m a t i o n . I n a d d i t i o n , Appendix 5 . 1 g i v e s t h r e e p e r f o r m a n c e m e a s u r e s f o r e a c h o f o u r 200 s t i m u l u s i t e m s so t h a t t h e i n t e r e s t e d i n v e s t i g a t o r can t e s t a d d i t i o n a l d e s c r i p t i o n s of orthographic s t r u c t u r e with these data. Since sublexical position-sensitive single-letter and b i g r a m c o u n t s a r e i m p o r t a n t components o f o r t h o g r a p h i c s t r u c t u r e , Appendix 5 . 2 and 5 . 3 p r e s e n t n o r m a t i v e c o u n t s b a s e d on a s a m p l e o f r o u g h l y o n e m i l l i o n words o f printed text. The o n l y c o u n t s c u r r e n t l y a v a i l a b l e i n p r i n t a r e T h e s e c o u n t s s h o u l d be based on a s a m p l e o n l y 2 % a s l a r g e v a l u a b l e t o r e s e a r c h e r s and educators interested i n the n o r m a t i v e s t r u c t u r e o f Eng 1i s h o r t h o g r a p h y The p r i m a r y o b j e c t i v e o f t h i s monograph i s t h e p r e s e n t a t i o n o f o u r new e m p i r i c a l and t h e o r e t i c a l r e s e a r c h . Because o f s p a c e l i m i t a t i o n s , we were u n a b l e t o r e v i e w much o f t h e o t h e r r e l e v a n t r e s e a r c h i n l e t t e r and word p e r c e p t i o n . For r e v i e w s o f t h i s r e s e a r c h , t h e r e a d e r is r e f e r r e d t o A l l p o r t ( 1 9 7 9 ) , Baron ( 1 9 7 8 ) , E s t e s ( 1 9 7 7 , 1 9 7 8 ) , G i b s o n and L e v i n ( 1 9 7 5 ) , Henderson ( 1 9 7 7 ) , J o h n s o n ( 1 9 7 7 1 , K r u e g e r ( 1 9 7 5 ) ,

.

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PREFACE

Massaro (1979).

(1975, 1978, 1979b, i n p r e s s ) , and P o l l a t s e k and

ix

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T h i s r e s e a r c h is t h e outcome of c o n t r i b u t i o n s o f f i v e time, t h e need t o relatively disparate researchers. In u n d e r s t a n d l e t t e r and word p e r c e p t i o n became t h e d r i v i n g , f o r c e a n d o u r o r i g i n a l b i a s e s a n d b e l i e f s were e v e n t u a l l y m o d i f i e d b y tests. If this actual experimentation and theortical c o n t r i b u t i o n b e n e f i t s r e a d i n g r e s e a r c h h a l f a s much a s i t b e n e f i t e d e a c h o f t h e p a r t i c i p a n t s from t h e c o l l a b o r a t i v e e f f o r t s , then t h e p r o j e c t can be considered t o be a success. T h i s r e s e a r c h e f f o r t h a s been s u p p o r t e d by f u n d s from t h e National I n s t i t u t e o f E d u c a t i o n t o t h e W i s c o n s i n R e s e a r c h an d Dev el o p m en t C e n t e r f o r I n d i v i d u a l i z e d S c h o o l i n g , U n i v e r s i t y o f J a c k Wende and Rod W i s c o n s i n , Madison, W is co n s i n 53706 U.S.A. McCoy c o n t r i b u t e d t o t h e d e v e l o p m e n t o f t h e c o m p u t e r - c o n t r o l l e d research f a c i l i t i e s . D a v i d K l i t z k e was r e s p o n s i b l e f o r some o f t h e computer programming, S u s a n C h i c o n e t e s t e d some o f t h e s u b j e c t s . J e n n i f e r A r g e l a n d e r e d i t e d and D o r i s K i n g t y p e d t h e manuscript using a not always straightforward computer-editing system. Bob C a v e y d r e w the many graphs. Don A n d e r s o n c o n t r i b u t e d t h e ABC p r i n t .


Contents vi i

PREFACE 1.

READING A N D I N F O R M A T I O N PROCESSING

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A n I n f o r m a t i o n Processing Model of Reading 2.

V I S U A L INFORMATION

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2

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11

Early W o r k 11 Feature Analysis 13 Letter F e a t u r e s 1 4 3.

Orthographic S t r u c t u r e

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23

Statistical Redundancy 2 4 P h o n o l o g i c a l l y Based D e s c r i p t i o n s 29 Rule-Governed R e g u l a r i t y 30 P h o n o l o g i c a l C o n s t r a i n t s 30 S c r i b a l C o n s t r a i n t s 31 Morphemic Featukes 3 2 Psychological Assumptions 34 D i c h o t o m y I s s u e 34 A n Initial Algorithm for Rule-Governed R e g u l a r i t y 35 4.

EXPERIMENTAL S T U D I E S

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Massaro e t a l . 1979 S t u d i e s 38 S t u d y 1: I n i t i a l R e p l i c a t i o n s 47 P r o c e d u r e 47 O r t h o g r a p h i c S t r u c t u r e 49 Similarity Effects 51 T a r g e t - C a t c h D i f f e r e n c e s 55 I n f o r m a t i o n P r o c e s s i n g Model 5 5 S t u d y 2: P r e c u e V e r s u s P o s t c u e 6 1 Orthographic Structure 63 S i m i l a r i t y E f f e c t s 64 T a r g e t Versus Catch T r i a l s 65 I n f o r m a t i o n P r o c e s s i n g Model 6 6 S t u d y 3: Mixed-Case 67 O r t h o g r a p h i c S t r u c t u r e 69 S i m i l a r i t y E f f e c t s 70 S t u d y 4 : L i m i t e d V i e w i n g Time 7 1 Orthographic Structure 71 S i m i l a r i t y E f f e c t s 72 Target Versus Catch T r i a l s 7 3 Discussion 73 S t u d y 5 : S p e e d e d RT T a s k w i t h Good V i s u a l I n f o r m a t i o n 7 3 Procedure 76 O r t h o g r a p h i c S t r u c t u r e 77 S t u d y 6: S p e e d e d RT T a s k w i t h Poor V i s u a l I n f o r m a t i o n 77 P r o c e d u r e 78 O r t h o g r a p h i c S t r u c t u r e 78 S t u d y 7 : H i g h - A c c u r a c y RT T a s k with Poor Visual Information 79 P r o c e d u r e 79 O r t h o g r a p h i c S t r u c t u r e 79 Summary o f A c c u r a c y a n d R e a c t i o n Time E x p e r i m e n t s 8 0 Overt Judgments 81 S t u d y 8: T y p i c a l i t y R a t i n g s 8 2 S t u d y 9: P o s i t i o n a l - F r e q u e n c y R a t i n g s Study 1 0 : R e g u l a r i t y Versus Positional-Frequency Judgments 87 Summary o f O v e r t J u d g m e n t E x p e r i m e n t s

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Appendix 4.1 D e t a i l s o f Method, P r o c e d u r e , a n d R e s u l t s o f S t u d y 1: I n i t i a l R e p l i c a t i o n 9 1 Method 9 1 R e s u l t s 94 A p p e n d i x 4.1A Rules for t h e Selection of O r t h o g r a p h i c a l l y Regular and I r r e g u l a r S t r i n g s 96 Appendix 4.18 T h e 2 0 0 S t i m u l u s Items Used i n S t u d i e s 1-10 97 Appendix 4.2 D e t a i l s o f Method, P r o c e d u r e , and R e s u l t s o f S t u d y 2: P r e c u e V e r s u s P o s t c u e 9 9 Method 9 9 R e s u l t s 100 Details o f Method, P r o c e d u r e , a n d Appendix 4.3 R e s u l t s o f S t u d y 3: M i x e d - C a s e 101 Method 01 Results 101 Appendix 4.4 D e t a i l s o f Method, P r o c e d u r e , a n d R e s u l t s o f S t u d y 4: L i m i t e d V i e w i n g T i m e 1 0 3 Method 103 Results 103 Appendix 4.5 D e t a i l s o f Method, P r o c e d u r e , a n d R e s u l t s o f S t u d y 5 : S p e e d e d RT T a s k w i t h Good V i s u a l I n f o r m a t i o n 1 0 5 Method 105 R e s u l t s 106 D e t a i l s o f Method, P r o c e d u r e , a n d Appendix 4.6 R e s u l t s o f S t u d y 6 : S p e e d e d RT T a s k w i t h Poor V i s u a l I n f o r m a t i o n 108 Method 108 R e s u l t s 108 Appendix 4.7 Details o f Method, P r o c e d u r e , a n d R e s u l t s o f S t u d y 7: H i g h - A c c u r a c y RT T a s k w i t h P o o r V i s u a l I n f o r m a t i o n 111 Method 111 R e s u l t s 111 Appendix 4.8 D e t a i l s of Method, P r o c e d u r e , a n d R e s u l t s o f S t u d y 8 : T y p i c a l i t y R a t i n g s 113 Method 113 R e s u l t s 114 A p p e n d i x 4.8A The P s e u d o w o r d s Used i n S t u d y 8 1 1 5

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CONTENTS Appendix 4.88 Directions for Typicality Ratings Without Words and for Typicality Ratings with Pseudowords 116 Appendix 4.8C Directions for Typicality Ratings with Words 117 Appendix 4.9 Details of Method, Procedure, and Results of Study 9: Positi,onal-Frequency Ratings 118 Method 118 Results 118 Appendix 4.9A Directions for Positional-Frequency Ratings 119 Appendix 4.10 Details of Method, Procedure, and Results of Study 10: Regularity Versus Positional-Frequency Paired-Judgments 120 Method 120 Results 121 Appendix 4.10A Regularity Instructions for Paired-Judgments 122 Appendix 4.108 Positional-Frequency Instructions for Paired-Judgments 123

5.

STRUCTURAL DESCRIPTIONS

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Descriptive Measures 125 Type Versus Token Counts 128 Scale of Frequency 130 Position-Sensitive Versus Position Insensitive Counts 132 The Most Effective Frequency Measure Frequency Versus Regularity 138 Within Class Analysis 140 Word Frequency 141 Multiple Regression 141 Summary 142

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Appendix 5.1 Stimulus Items and Results 143 Appendix 5.2 Single-Letter Positional Frequencies Three-letter Words 150 Four-letter Words 152 Five-letter Words 154 Six-letter Words 156 Seven-letter Words 158

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CONTENTS Appendix 5.3 Bigrarn Positional Frequencies Three-letter Words 161 Four-letter Words 172 Five-letter Words 188 Six-letter Words 205 Seven-letter Words 224 6.

SUMMARY AND CONCLUSIONS

REFERENCES 249 GLOSSARY 263 AUTHOR INDEX 269 SUBJECT INDEX 275

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1

Reading and Information Processing

The p r o c e s s e s by w h i c h w o r d s a r e r e c o g n i z e d d u r i n g r e a d i n g h a v e c o n c e r n e d p s y c h o l o g i s t s and e d u c a t o r s f o r almost a c e n t u r y . The b a s i c a s s u m p t i o n i s t h a t a t h o r o u g h u n d e r s t a n d i n g o f t h e p r o c e s s e s i n v o l v e d i n word r e c o g n i t i o n w i l l a f f o r d a m a j o r a d v a n c e i n t h e u n d e r s t a n d i n g o f how p e o p l e r e a d . Every m a j o r t r e a t i s e o n r e a d i n g f r o m Huey ( 1 9 0 8 / 1 9 6 8 ) t o G i b s o n an d Levin (1975) h a s d i s c u s s e d t h i s issue a t l e n g t h , b u t g e n e r a l l y h a s c o n c l u d e d , a s d i d Huey ( 1 9 0 8 / 1 9 6 8 , p. 1 0 2 ) , t h a t " i t i s v e r y d i f f i c u l t t o draw f i n a l c o n c l u s i o n s c o n c e r n i n g v i s u a l perception i n reading.. R e c e n t l y two d i f f e r e n t p a n e l s w h i c h recommended f u n d i n g priorities in b a s i c s k i l l s research t o the National Institute o f E d u c a t i o n a s s i g n e d h i g h p r i o r i t i e s t o s t u d i e s o n word recognition. Consequently, a high p r i o r i t y c u r r e n t l y is being g i v e n t o o b t a i n i n g a b e t t e r u n d e r s t a n d i n g o f word r e c o g n i t i o n w i t h s t r e s s on t h e basic s t a g e s of v i s u a l i n f o r m a t i o n processing. I n f o r m a t i o n p r o c e s s i n g d u r i n g r e a d i n g is c u r r e n t l y t h e p r i m a r y c o n c e r n o f many e x p e r i m e n t a l p s y c h o l o g i s t s , and t h e r e f o r e , a n e x p a n d i n g body o f e x p e r i m e n t a l d a t a i s b e i n g b r o u g h t t o b e a r on t h e s e q u e s t i o n s . S i n c e word r e c o g n i t i o n f o r m s a b r i d g e b e t w e e n v i s u a l i n f o r m a t i o n p r o c e s s i n g s k i l l s an d i t i s i m p o r t a n t f o r u n d e r s t a n d i n g how t h e two comprehension, r e l a t e t o each o t h e r . R e s e a r c h o n word r e c o g n i t i o n p r o c e s s e s is s e e n a s h a v i n g a h i g h p o t e n t i a l f o r improving r e a d i n g i n s t r u c t i o n . Good an d po o r r e a d e r s h a v e b e e n shown t o d i f f e r i n p e r f o r m a n c e o n a v a r i e t y of general t a s k s b u t u n t i l r e c e n t l y , l i t t l e attempt has b e e n made t o e x p l o r e how c h i l d r e n w i t h d i f f e r e n t l e v e l s o f reading a b i l i t y might d i f f e r in b a s i c word r e c o g n i t i o n p r o c e s s e s . We b e l i e v e t h a t b a s i c word r e c o g n i t i o n p r o c e s s e s ,

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2

CHAPTER 1

once d e f i n e d f o r c o m p e t e n t a d u l t r e a d e r s , c a n be used t o a s s e s s word r e c o g n i t i o n a b i l i t i e s o f good and p o o r r e a d e r s i n t h e elementary grades. ~f good and poor r e a d e r s u t i l i z e t h e same p r o c e s s e s , b u t d i f f e r i n speed or a c c u r a c y , t h e n r e m e d i a t i o n methods b a s e d o n common a p p r o a c h e s t o r e a d i n g i n s t r u c t i o n would be w a r r a n t e d . However, i f fundamental d i f f e r e n c e s i n v i s u a l recognition processes a r e found, then t o t a l l y d i f f e r e n t r e m e d i a l methods would be r e q u i r e d . The o v e r a l l o b j e c t i v e of t h i s r e s e a r c h p r o j e c t i s t o a s s e s s how t h e r e a d e r ' s h i g h e r - o r d e r knowledge of t h e l a n g u a g e i n t e r a c t s with lower-level perceptual analyses during reading. The s p e c i f i c q u e s t i o n t h a t is a d d r e s s e d i s how t h e r e a d e r ' s a b s t r a c t knowledge a b o u t o r t h o g r a p h i c s t r u c t u r e is combined w i t h t h e i n f o r m a t i o n d e r i v e d from v i s u a l f e a t u r a l a n a l y s i s i n word r e c o g n i t i o n . Orthographic structure refers t o the spelling constraints in a w r i t t e n l a n g u a g e . T h e r e is a c o n s i d e r a b l e amount o f p r e d i c t a b i l i t y i n E n g l i s h w r i t i n g , f o r example, and t h e r e a d e r may a c t i v e l y u t i l i z e t h i s i n f o r m a t i o n i n word r e c o g n i t i o n . V i s u a l f e a t u r a l a n a l y s i s r e f e r s t o t h e e v a l u a t i o n o f component p r o p e r t i e s o f l e t t e r s i n t h e c o u r s e o f l e t t e r and word r e c o g n i t i o n . Given e v i d e n c e t h a t b o t h o f t h e s e s o u r c e s o f i n f o r m a t i o n c o n t r i b u t e t o word r e c o g n i t i o n , t h e g o a l i s t o d e f i n e what i n f o r m a t i o n t h e r e a d e r a c t u a l l y u t i l i z e s ( w h a t i n f o r m a t i o n i s p s y c h o l o g i c a l l y r e a l ) and t o d e f i n e how t h e s e s o u r c e s of information a r e integrated together in reading. This r e q u i r e s examination of the psychological r e a l i t y of v a r i o u s d e s c r i p t i o n s of v i s u a l f e a t u r e s , of o r t h o g r a p h i c s t r u c t u r e , and of q u a n t i t a t i v e models t h a t d e s c r i b e how v i s u a l f e a t u r e s and o r t h o g r a p h i c s t r u c t u r e a r e i n t e g r a t e d d u r i n g word p e r c e p t i o n and r e c o g n i t i o n .

AN INFORMATION PROCESSING MODEL OF R E A D I N G

E v a l u a t i o n of t h e c o n t r i b u t i o n s o f v i s u a l f e a t u r e s and o r t h o g r a p h i c s t r u c t u r e t o word r e c o g n i t i o n r e q u i r e s t h a t we d e s c r i b e i n some d e t a i l t h e p r o c e s s e s i n v o l v e d i n r e a d i n g . The model f o r d e s c r i b i n g t h e s e p r o c e s s e s is p a r t of a more g e n e r a l l a n g u a g e p r o c e s s i n g model which h a s been d e v e l o p e d and t e s t e d over t h e p a s t few y e a r s ( M a s s a r o , 1 9 7 5 , 1 9 7 8 , 1 9 7 9 a ) . F i g u r e 1.1 p r e s e n t s a s c h e m a t i c r e p r e s e n t a t i o n of t h e s t a g e s of processing i n reading. A t e a c h s t a g e of p r o c e s s i n g , memory and p r o c e s s components a r e r e p r e s e n t e d . Each memory component ( i n d i c a t e d by a r e c t a n g l e ) c o r r e s p o n d s t o t h e i n f o r m a t i o n a v a i l a b l e a t a p a r t i c u l a r s t a g e of p r o c e s s i n g . Each p r o c e s s

R E A D I N G AND INFORMATION PROCESSING

3

component ( i n d i c a t e d by a c i r c l e ) c o r r e s p o n d s t o t h e o p e r a t i o n s a p p l i e d t o t h e i n f o r m a t i o n h e l d by t h e memory component. The memory components a r e t e m p o r a r y s t o r a g e s e x c e p t f o r l o n g - t e r m memory which i s r e l a t i v e l y permanent and, i n a d d i t i o n , s u p p l e m e n t s t h e i n f o r m a t i o n a t some of t h e p r o c e s s i n g s t a g e s . T h i s model p r o v i d e s a framework from which h y p o t h e s e s a b o u t word r e c o g n i t i o n c a n be d e r i v e d and t e s t e d . The t y p i c a l t e x t i n r e a d i n g i s a s e q u e n c e of l e t t e r s and s p a c e s which conform t o o r t h o g r a p h i c , s y n t a c t i c , and s e m a n t i c The a v e r a g e E n g l i s h c o n s t r a i n t s of t h e w r i t t e n l a n g u a g e . r e a d e r b e g i n s a t t h e t o p l e f t - h a n d c o r n e r of t h e p a g e and r e a d s e a c h l i n e from l e f t t o r i g h t . The r e a d e r ' s e y e movements a c r o s s a l i n e a r e n o t c o n t i n u o u s b u t occur i n a s e r i e s of s h o r t jumps c a l l e d s a c c a d e s . The f i x a t i o n time between s a c c a d e s i s r o u g h l y t e n times l o n g e r t h a n t h e s a c c a d e . The t y p i c a l s a c c a d e of 1 t o 2 d e g r e e s r e q u i r e s 2 0 t o 30 msec, w h e r e a s f i x a t i o n t i m e a v e r a g e s 250 msec ( S h e b i l s k e , 1 9 7 5 ; Woodworth, 1 9 3 8 ) . I n i t i a l p r o c e s s i n g of t h e v i s u a l s t i m u l u s m u s t O C C U K d u r i n g t h e f i x a t i o n time b e c a u s e t h e s t i m u l u s p a t t e r n i s b l u r r e d d u r i n g a s a c c a d e and i t s d u r a t i o n i s t o o s h o r t f o r s u f f i c i e n t p r o c e s s i n g t o occur. During a n e y e f i x a t i o n , t h e l i g h t p a t t e r n r e f l e c t e d from l e t t e r s i s t r a n s d u c e d by t h e v i s u a l r e c e p t o r s and a p r o c e s s d e t e c t s and t r a n s m i t s v i s u a l f e a t u r e s t o p r e p e r c e p t u a l v i s u a l s t o r a g e ( s e e F i g u r e 1 . 1 ) . I n o u r model, w e c a l l t h i s i n i t i a l p r o c e s s f e a t u r e d e t e c t i o n . The f e a t u r e s a r e d e s c r i b e d a s v i s u a l b e c a u s e i t i s assumed t h a t t h e r e i s a d i r e c t r e l a t i o n s h i p between t h e s t i m u l u s p r o p e r t i e s o f t h e l e t t e r s and

LONG TERM MEMORY

t

MEMORY

F i g u r e 1.1

A s t a g e model

T

MEMORY

of r e a d i n g p r i n t e d t e x t .

CHAPTER 1

t h e i n f o r m a t i o n i n p r e p e r c e p t u a l v i s u a l s t o r a g e . The p a s s i v e t r a n s d u c t i o n of f e a t u r e d e t e c t i o n c o n t r a s t s w i t h t h e a c t i v e c o n s t r u c t i o n of t h e s u b s e q u e n t p r o c e s s i n g s t a g e s . There is no e x a c t one-to-one r e l a t i o n s h i p between t h e i n p u t and o u t p u t o f the following processing s t a g e s s i n c e these l a t e r s t a g e s a c t i v e l y u t i l i z e i n f o r m a t i o n s t o r e d i n l o n g - t e r m memory. Given t h e s e t o f v i s u a l f e a t u r e s i n p r e p e r c e p t u a l v i s u a l storage, t h e primary recognition process attempts t o transform t h e s e i s o l a t e d f e a t u r e s i n t o a s e q u e n c e of l e t t e r s and s p a c e s i n s y n t h e s i z e d v i s u a l memory. To do t h i s , t h e primary r e c o g n i t i o n p r o c e s s can u t i l i z e i n f o r m a t i o n h e l d i n long-term memory which f o r t h e a c c o m p l i s h e d r e a d e r i n c l u d e s a l i s t o f f e a t u r e s f o r e a c h l e t t e r of t h e a l p h a b e t a l o n g w i t h i n f o r m a t i o n a b o u t t h e o r t h o g r a p h i c s t r u c t u r e o f t h e l a n g u a g e . The p r i m a r y r e c o g n i t i o n process u t i l i z e s both t h e v i s u a l f e a t u r e s i n p r e p e r c e p t u a l s t o r a g e and knowledge of o r t h o g r a p h i c s t r u c t u r e i n i t s s y n t h e s i s o f t h e l e t t e r s t r i n g s . The t i m e - h o n o r e d b e l i e f t h a t r e c o g n i t i o n of l e t t e r s t r i n g s becomes p r o g r e s s i v e l y e a s i e r a s t h e s t r i n g s more c l o s e l y a p p r o x i m a t e words i m p l i e s t h a t r e a d e r s c a p i t a l i z e on t h e p r e s e n c e of o r t h o g r a p h i c structure. R e c o g n i t i o n u s u a l l y means t h e p r o c e s s o f d i s c r i m i n a t i n g , i d e n t i f y i n g , and c o r r e c t l y o r d e r i n g t h e l e t t e r s o f a l e t t e r s t r i n g ( S m i t h , 1 9 7 1 ) . Given t h i s i n t e r p r e t a t i o n o f recognition, t h e f a c i l i t a t i n g e f f e c t of o r t h o g r a p h i c s t r u c t u r e on l e t t e r - s t r i n g r e c o g n i t i o n m u s t a l m o s t b e t r u e by d e f i n i t i o n . R e c o g n i t i o n i n v o l v e s a c c e s s i n g knowledge b u i l t up t h r o u g h e x p e r i e n c e . I t is o n l y n a t u r a l t h a t a r e a d e r ' s experience w i t h t o wordlike than nonwordlike words w i l l g e n e r a l i z e more s t r i n g s . Our g o a l s i n t h i s r e s e a r c h e n d e a v o r a r e t o p r o v i d e a b e t t e r u n d e r s t a n d i n g o f t h e r e c o g n i t i o n p r o c e s s and t o e v a l u a t e which a s p e c t s o f o r t h o g r a p h i c s t r u c t u r e t h e r e a d e r knows and utilizes. The c e n t r a l a s s u m p t i o n a d d r e s s e d h e r e i s t h a t o r t h o g r a p h i c structure influences perceptual recognition (primary r e c o g n i t i o n i n our m o d e l ) , i n a d d i t i o n t o o t h e r i n f l u e n c e s a t l a t e r s t a g e s o f p r o c e s s i n g . We b e l i e v e t h a t o r t h o g r a p h i c s t r u c t u r e a l s o f a c i l i t a t e s p r o c e s s i n g from a p e r c e p t u a l t o a c o n c e p t u a l l e v e l ( s e c o n d a r y r e c o g n i t i o n i n our m o d e l ) . By f o c u s i n g on t h e f a c i l i t a t i n g e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e aligned ourselves with a on v i s u a l p e r c e p t i o n , w e h a v e t r a d i t i o n o v e r 100 y e a r s o l d c o n c e r n e d w i t h how knowledge influences perception. James (1890/1950, p. 4 4 4 ) c a p t u r e d t h e s p i r i t o f t h e work begun by Wundt w i t h t h e o f t e n q u o t e d statement, "...the o n l y t h i n g s which w e commonly s e n a r e t h o s e which w e p r e p e r c e i v e . "


5

In our model, t h e primary r e c o g n i t i o n p r o c e s s e v a l u a t e s t h e f e a t u r e s i n p r e p e r c e p t u a l v i s u a l s t o r a g e and compares o r m a t c h e s t h e s e f e a t u r e s t o d e s c r i p t i o n s of p e r c e p t u a l u n i t s i n l o n g - t e r m memory. A p e r c e p t u a l u n i t o r p r o t o t y p e r e p r e s e n t s e a c h o f t h e l e t t e r s i n l o n g - t e r m memory a s i t would be i d e a l l y represented in preperceptual v i s u a l s t o r a g e . The p r i m a r y recognition process seeks for each l e t t e r position the p e r c e p t u a l p r o t o t y p e t h a t p r o v i d e s t h e b e s t match t o t h e It is a t primary r e c o g n i t i o n t h a t f e a t u r a l information. orthographic s t r u c t u r e reduces uncertainty or contributes information. The outcome of p r i m a r y r e c o g n i t i o n i s , t h e r e f o r e , t h e j o i n t p r o d u c t of f e a t u r a l i n f o r m a t i o n i n p r e p e r c e p t u a l v i s u a l s t o r a g e and knowledge of l e t t e r c o n s t r a i n t s i n l o n g - t e r m memory. S i n c e t h e r e a r e a l i m i t e d number of ways t h a t s e q u e n c e s o f l e t t e r s and l e t t e r g r o u p s c a n be a s s e m b l e d t o form E n g l i s h w o r d s , knowledge of t h e s e s e q u e n c e s c a n h e l p t h e r e a d e r t o r e s o l v e t h e l e t t e r s i n s t r i n g s t h a t conform t o t h e l a n g u a g e ( c f . M a s s a r o , 1 9 7 5 , C h a p t e r 7 ) . I t a l s o h a s been h y p o t h e s i z e d t h a t t h i s knowledge c a n a s s i s t t h e r e a d e r i n d e t e r m i n i n g t h e r e l a t i v e p o s i t i o n s of l e t t e r s o n c e t h e y a r e r e c o g n i z e d ( E s t e s , 1 9 7 5 a , 1 9 7 5 b ) . For e x a m p l e , g i v e n t h e l e t t e r s &, knowledge of o r t h o g r a p h i c s t r u c t u r e d o e s n o t a l l o w t h e s e l e t t e r s t o be r e a d i n t h e o p p o s i t e o r d e r . However, G e o f f r i o n ( 1 9 7 6 ) found t h a t t h e c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e is n o t d e p e n d e n t on determining t h e r e l a t i v e p o s i t i o n s of l e t t e r s . In a d d i t i o n , r e c e n t r e s e a r c h by MaSSaKO ( 1 9 7 9 a ) f o u n d a l a r g e e f f e c t of o r t h o g r a p h i c s t r u c t u r e on l e t t e r r e c o g n i t i o n b u t no e f f e c t on t h e d e t e r m i n a t i o n of r e l a t i v e s p a t i a l p o s i t i o n . In the present research, the experiments are designed such t h a t any s t r u c t u r e a t primary f a c i l i t a t i n g e f f e c t of o r t h o g r a p h i c r e c o g n i t i o n m u s t be d u e t o l e t t e r r e c o g n i t i o n and n o t p o s i t i o n uncertainty The p r i m a r y r e c o g n i t i o n p r o c e s s o p e r a t e s on a number o f l e t t e r s s i m u l t a n e o u s l y ( i n p a r a l l e l ) . The v i s u a l f e a t u r e s d e t e c t e d a t each s p a t i a l l o c a t i o n d e f i n e a s e t of p o s s i b l e l e t t e r s for that position. The p r i m a r y r e c o g n i t i o n p r o c e s s c h o o s e s from t h i s s e t of c a n d i d a t e s t h e l e t t e r a l t e r n a t i v e which h a s t h e b e s t c o r r e s p o n d e n c e i n t e r m s o f v i s u a l f e a t u r e s . However, t h e s e l e c t i o n of a b e s t c o r r e s p o n d e n c e c a n be f a c i l i t a t e d by knowledge of orthographic structure. The primary r e c o g n i t i o n p r o c e s s , t h e r e f o r e , a t t e m p t s t o u t i l i z e both t h e f e a t u r a l information i n preperceptual s t o r a g e and knowledge a b o u t t h e s t r u c t u r e of legal latter strings. A c r i t i c a l c o n c e r n i s w i t h t h e i n t e r a c t i o n of t h e s e two s o u r c e s

.

CHAPTER 1

of i n f o r m a t i o n ; i n o u r m o d e l , i t is assumed t h a t t h e two s o u r c e s o f i n f o r m a t i o n make independent c o n t r i b u t i o n s t o p r i m a r y r e c o g n i t i o n ( M a s s a r o , 1 9 7 3 , 1 9 7 5 , 1 9 7 8 , 1979b; Thompson & Massaro, 1 9 7 3 ) . The p r e s e n t a n a l y s i s o f t h e f a c i l i t a t i o n o f o r t h o g r a p h i c s t r u c t u r e i n l e t t e r r e c o g n i t i o n is i d e n t i c a l i n s p i r i t t o t h e o r i g i n a l a n a l y s i s p r o v i d e d by M i l l e r , B r u n e r , and Postman ( 1 9 5 4 ) . They o b s e r v e d t h a t t h e number of l e t t e r s c o r r e c t l y r e p o r t e d from a tachistoscopic exposure increased with increases in familiarity of the letter pattern. The f a m i l i a r i t y of t h e l e t t e r s e q u e n c e s was v a r i e d by t h e d e g r e e t o which t h e s e q u e n c e a p p r o x i m a t e d p r i n t e d E n g l i s h (Shannon, 1948). U t i l i z i n g t h e t h e o r y of i n f o r m a t i o n d e v e l o p e d by Shannon ( 1 9 4 8 ) , however, t h e y o b s e r v e d t h a t t h e number o f l e t t e r s r e p o r t e d i s n o t a d i r e c t i n d e x o f t h e amount of s t i m u l u s i n f o r m a t i o n d e r i v e d from t h e e x p o s u r e i t s e l f s i n c e t h e redundancy o f c o n t e x t u a l l y c o n s t r a i n e d s e q u e n c e s i s n o t t a k e n i n t o account. M i l l e r e t a l . (1954) c a l c u l a t e d t h e redundancy o f t h e i r sequences a t each o r d e r of approximation t o E n g l i s h u sin g t h e c o u n t s g i v e n by Shannon ( 1 9 5 1 ) and c o u n t s o f t h e i r own. When p e r f o r m a n c e was c o r r e c t e d f o r r e d u n d a n c y , t h e r e was n o e f f e c t (see a l s o T u l v i n g , 1 9 6 3 ) . T h i s r e s u l t was of f a m i l i a r i t y i n t e r p r e t e d t o mean t h a t t h e amount o f s t i m u l u s i n f o r m a t i o n r e c e i v e d from t h e e x p o s u r e d i d n o t depend on t h e f a m i l i a r i t y o f the l e t t e r pattern. I n t e r m s o f o u r a n a l y s i s , o v e r two d e c a d e s l a t e r , t h e r e s u l t s c a n b e i n t e r p r e t e d t o mean t h a t o r t h o g r a p h i c s t r u c t u r e and v i s u a l i n f o r m a t i o n c o n t r i b u t e i n d e p e n d e n t s o u r c e s of i nformat i on i n r ead i n g . The c u r r e n t view was d e v e l o p e d , i n p a r t , o n t h e b a s i s o f e x p e r i m e n t s c a r r i e d o u t u s i n g t h e Reicher-Wheeler paradigm i n word r e c o g n i t i o n ( R e i c h e r , 1969; W h e e l e r , 1 9 7 0 ; Thompson & Massaro, 1 9 7 3 ) . I n t h i s paradigm, s u b j e c t s a r e p r e s e n t e d w i t h e i t h e r a t e s t word o r a s i n g l e t e s t l e t t e r f o r a s h o r t d u r a t i o n f o l l o w e d i m m e d i a t e l y by a masking s t i m u l u s and two r e s p o n s e alternatives. The r e s p o n s e a l t e r n a t i v e s b o t h s p e l l words i n t h e t e s t word c o n d i t i o n ; f o r example, g i v e n t h e t e s t s t i m u l u s WORD, t h e r e s p o n s e a l t e r n a t i v e s ---g and ---E would be presented. I n the corresponding s i n g l e test l e t t e r condition, -D i s p r e s e n t e d and f o l l o w e d by t h e r e s p o n s e a l t e r n a t i v e s g and K. I n t h e s e s t u d i e s , r e c o g n i t i o n of t h e t e s t word i s a b o u t 1 0 % b e t t e r t h a n r e c o g n i t i o n of t h e t e s t l e t t e r . i t is Given t h e t w o - a l t e r n a t i v e f o r c e d - c h o i c e c o n t r o l , assumed t h a t t h e r e a d e r u t i l i z e s o r t h o g r a p h i c s t r u c t u r e t o e l i m i n a t e p o s s i b l e a l t e r n a t i v e s d u r i n g t h e p e r c e p t i o n of t h e


t e s t d i s p l a y (Thompson & M a s s a r o , 1 9 7 3 ) . A s a n e x a m p l e , p r e s e n t e d w i t h t h e t e s t s t i m u l u s WORD and g i v e n r e c o g n i t i o n of t e s t l e t t e r s WOR and a c u r v i l i n e a r segment of t h e f i n a l l e t t e r , t h e r e a d e r c o u l d n a r r o w down t h e a l t e r n a t i v e s f o r t h e f i n a l 0, and Q. I f 0 and Q a r e c o n s i d e r e d t o be l e t t e r t o D, orthographically i l l e g a l i n the context then D r e p r e s e n t s a n unambiguous c h o i c e . The r e a d e r w i l l t h e r e f o r e p e r c e i v e t h e word WORD g i v e n j u s t p a r t i a l i n f o r m a t i o n a b o u t t h e f i n a l letter. If t h e r e a d e r r e c o g n i z e s t h e same c u r v i l i n e a r segment i n t h e c o r r e s p o n d i n g s i n g l e t e s t l e t t e r c o n d i t i o n , h o w e v e r , any o f t h e t h r e e l e t t e r s ( D , 0 , and Q ) a r e p o s s i b l e and t h e perceptual s y n t h e s i s w i l l r e s u l t i n D o n l y one o u t of t h r e e times. What is c r i t i c a l i n t h i s a n a l y s i s i s t h a t t h e b e t t e r p e r f o r m a n c e on words compared t o s i n g l e l e t t e r s i s o b t a i n e d even though t h e v i s u a l f e a t u r a l i n f o r ma tio n a v a i l a b l e t o t h e p r i m a r y r e c o g n i t i o n p r o c e s s i s e q u i v a l e n t i n t h e word and l e t t e r conditions. The o r t h o g r a p h i c s t r u c t u r e of t h e word simply p r o v i d e s an a d d i t i o n a l b u t i n d e p e n d e n t s o u r c e of information. The f e a t u r a l information available t o the recognition process does not change with changes i n orthographic structure. In t h i s view, although o r t h o g r a p h i c s t r u c t u r e f a c i l i t a t e s word p e r c e p t i o n , i t d o e s n o t modify t h e f e a t u r e a n a l y s i s of t h e p r i n t e d p a t t e r n (Krueger & S h a p i r o , 1979; Massaro, 1 9 7 9 a ) . As ure h a v e d i s c u s s e d , one r o l e of o r t h o g r a p h i c s t r u c t u r e is c o n c e n t r a t e d i n t h e p r i m a r y r e c o g n i t i o n p r o c e s s and s e r v e s t o f a c i l i t a t e the recognition of individual l e t t e r s . In a d d i t i o n , o r t h o g r a p h i c s t r u c t u r e is f u n c t i o n a l a t l a t e r s t a g e s of p r o c e s s i n g , such a s i t s f a c i l i t a t i n g e f f e c t i n short-term memory ( M a s s a r o , i n p r e s s ) . Baddeley ( 1 9 6 4 ) , f o r e x a m p l e , showed t h a t a w e l l - s t r u c t u r e d s t r i n g o f l e t t e r s i s e a s i e r t o remember and r e c a l l t h a n a random s t r i n g . Whether o r t h o g r a p h i c structure f a c i l i t a t e s perceptual recognition is a more c o n t r o v e r s i a l i s s u e . We assume t h a t i t i s u t i l i z e d i n t h e f o l l o w i n g manner. Upon p r e s e n t a t i o n of a l e t t e r s t r i n g , t h e p r i m a r y r e c o g n i t i o n p r o c e s s b e g i n s i n t e g r a t i n g and s y n t h e s i z i n g f e a t u r a l i n f o r m a t i o n p a s s e d on by feature detection t o preperceptual visual storage. Featural information is resolved a t d i f f e r e n t r a t e s and t h e r e i s some e v i d e n c e t h a t g r o s s f e a t u r e s a r e a v a i l a b l e b e f o r e t h e more d e t a i l e d f e a t u r e s ( M a s s a r o & S c h m u l l e r , 1 9 7 5 ) . The p r i m a r y r e c o g n i t i o n p r o c e s s is faced with a succession of partial information s t a t e s . These partial visual information states are s u p p l e m e n t e d w i t h knowledge about orthographic s t r u c t u r e . Assume, f o r e x a m p l e , a n i n i t i a l g h a s been p e r c e i v e d i n a

m,

8

CHAPTER 1

l e t t e r s t r i n g , and t h e f e a t u r e s a v a i l a b l e f o r t h e n e x t l e t t e r eliminate a l l a l t e r n a t i v e s except c o r g . The p r i m a r y recognition process might synthesize 5 without waiting f o r f u r t h e r v i s u a l i n f o r m a t i o n , s i n c e i n i t i a l the i s n o t a c c e p t a b l e w h i l e i n i t i a l the i s . The p r i m a r y r e c o g n i t i o n p r o c e s s t r a n s m i t s a s e q u e n c e o f r e c o g n i z e d l e t t e r s t o s y n t h e s i z e d v i s u a l memory. F i g u r e 1.1 shows h o r t h e s e c o n d a r y r e c o g n i t i o n p r o c e s s t r a n s f o r m s t h i s s y n t h e s i z e d v i s u a l p e r c e p t i n t o m e a n i n g f u l form i n g e n e r a t e d a b s t r a c t memory. W e a s s u m e s e c o n d a r y r e c o g n i t i o n a t t e m p t s t o c l o s e o f f t h e l e t t e r s t r i n g i n t o a word. The s e c o n d a r y r e c o g n i t i o n p r o c e s s makes t h i s t r a n s f o r m a t i o n by f i n d i n g t h e b e s t m a t c h b e t w e e n t h e l e t t e r s t r i n g a nd a word i n t h e l e x i c o n i n l o n g - t e r m memory. Knowledge o f o r t h o g r a p h i c s t r u c t u r e c a n a l s o c o n t r i b u t e t o s e c o n d a r y r e c o g n i t i o n ; word r e c o g n i t i o n c a n o c c u r w i t h o u t c o m p l e t e r e c o g n i t i o n o f a l l o f t h e co m p o n en t l e t t e r s . G i v e n t h e l e t t e r s & and t h e v i a b l e a l t e r n a t i v e s 1. and t i n f i n a l p o s i t i o n , o n l y J makes a w o r d , an d t h e r e f o r e word i d e n t i f i c a t i o n ( l e x i c a l a c c e s s ) c a n b e . a c h i e v e d ( M a s s a r o , 1 9 7 7 ) . Each word i n t h e l e x i c o n c o n t a i n s b o t h p e r c e p t u a l and c o n c e p t u a l c o d e s . The word w h i c h i s r e c o g n i z e d i s t h e o n e whose p e r c e p t u a l c o d e g i v e s t h e b e s t m a t c h an d whose c o n c e p t u a l code is most a p p r o p r i a t e i n t h a t p a r t i c u l a r c o n t e x t . G e n e r a t e d a b s t r a c t memory c o r r e s p o n d s t o t h e s h o r t - t e r m o r w o r k i n g memory o f m o s t i n f o r m a t i o n p r o c e s s i n g m o d e l s . In our m o d e l , t h i s memory i s common t o b o t h s p e e c h p e r c e p t i o n an d reading. R eco d i n g and r e h e a r s a l p r o c e s s e s b u i l d and m a i n t a i n s e m a n t i c and s y n t a c t i c s t r u c t u r e s a t t h e l e v e l o f g e n e r a t e d a b s t r a c t memory. I t i s a l s o p o s s i b l e t o g o f r o m m ean i n g t o a visual or auditory percept in o u r model. The r e c o d i n g o p e r a t i o n c a n t r a n s f o r m t h e meaning o f a c o n c e p t i n t o i t s s u r f a c e s t r u c t u r e i n an a u d i t o r y o r v i s u a l form. Two i s s u e s c o n c e r n i n g l e t t e r a n d word r e c o g n i t i o n i n reading w i l l be addressed i n t h e present research. F i r s t , what a r e t h e v i s u a l f e a t u r e s o f l e t t e r s u t i l i z e d by t h e primary r e c o g n i t i o n p r o c e s s ? S e c o n d , how i s k n o w l ed g e o f o r t h o g r a p h i c structure psychologically r e p r e s e n t e d ? To address these i s s u e s , a n y s t u d y m u s t b e c o n c e r n e d w i t h how t h e s e s o u r c e s o f information a r e evaluated, integrated , and co m b i n ed i n perceptual recognition ( M a s s a r o , 1 9 7 9 b ) . The d i s c u s s i o n o f v i s u a l f e a t u r e s is p r e s e n t e d i n Chapter 2 and t h e d i s c u s s i o n of o r t h o g r a p h i c s t r u c t u r e i s p r e s e n t e d i n C h a p t e r 3 . The f o u r t h c h a p t e r f o c u s e s o n how t h e r e a d e r u t i l i z e s b o t h s o u r c e s o f i n f o r m a t i o n i n a v a r i e t y o f p e r c e p t u a l r e c o g n i t i o n an d o v e r t


9

judgment tasks. To s u s t a i n t h e l o g i c a l c o n t i n u i t y of the p r e s e n t a t i o n of the experiments, d e t a i l s of t h e method, procedure, an d r e s u l t s a r e p l a c e d i n a p p e n d i c e s a t t h e en d of t h e c h a p t e r . The f i f t h c h a p t e r p r e s e n t s a d e t a i l e d e v a l u a t i o n Of t h e p s y c h o l o g i c a l reality of many d e s c r i p t i o n s of orthographic structure. The d a t a b a s e d e r i v e d f r o m t h e p r e s e n t e x p e r i m e n t s is a l s o p r e s e n t e d t o a l l o w a d d i t i o n a l t e s t s o f In addition, o t h e r d e s c r i p t i o n s of o r t h o g r a p h i c s t r u c t u r e . n o r m a t i v e c o u n t s o f l e t t e r and l e t t e r c l u s t e r o c c u r r e n c e s in These c o u n t s m a k e p o s s i b l e t h e measurement t e x t are presented. o f a v a r i e t y o f s t i m u l u s and t e s t i t e m s a c c o r d i n g t o a number of formal d e s c r i p t i o n s of o r t h o g r a p h i c s t r u c t u r e . The l a s t c h a p t e r s u m m a r i z e s t h e c o n t r i b u t i o n s of t h e p r e s e n t r e s e a r c h . The c e n t r a l c o n c e r n o f t h e e m p i r i c a l and t h e o r e t i c a l work p r e s e n t e d h e r e is t o e v a l u a t e t h e n a t u r e of t h e p r o c e s s e s i n v o l v e d i n l e t t e r a n d word r e c o g n i t i o n and t o d i s c o v e r how kn o wl ed g e a b o u t o r t h o g r a p h i c s t r u c t u r e is r e p r e s e n t e d and utilized.


2

Visual Information

Most of t h e t r a d i t i o n a l research relevant to visual i n f o r m a t i o n i n r e a d i n g h a s been c o n c e r n e d w i t h t h e l e g i b i l i t y of v a r i o u s t y p e f o n t s and t e x t f o r m a t s . S p e n c e r (1969) summarizes t h i s work i n an a d e q u a t e and i n t e r e s t i n g manner and we w i l l not attempt to duplicate a d e t a i l e d coverage here. A f t e r m e n t i o n i n g a few g e n e r a l p r i n c i p l e s of t h e l e g i b i l i t y o f p r i n t e d t e x t , we w i l l p r o v i d e some d i s c u s s i o n of t h e r o l e of f e a t u r e t h e o r i e s i n d e s c r i b i n g how l e t t e r s a r e recognized. Finally, we will evaluate the functional p r o p e r t i e s o f t h e t y p e f o n t s used i n o u r e x p e r i m e n t s s i n c e t h i s i n f o r m a t i o n w i l l be n e c e s s a r y i n o u r s t u d i e s o f how v i s u a l i n f o r m a t i o n and o r t h o g r a p h i c s t r u c t u r e c o n t r i b u t e t o p e r c e p t u a l recognition.

E A R L Y WORK

Much o f t h e e a r l y work r e v e a l e d t h a t l e t t e r s a r e n o t e q u a l l y l e g i b l e . T a b l e 2 . 1 p r e s e n t s t h e r a n k o r d e r of t h e l e g i b i l i t y o f t h e l o w e r c a s e l e t t e r s i n an e x p e r i m e n t by C a t t e l l i n 1885 ( c i t e d i n Anderson & D e a r b o r n , 1952) and a n e x p e r i m e n t i n o u r l a b o r a t o r y some 90 y e a r s l a t e r . E x c e p t f o r a few of t h e l e t t e r s s u c h a s 9, 5 , and 1, t h e r e is an i m p r e s s i v e a g r e e m e n t between t h e two s t u d i e s . Both s t u d i e s found t h a t some of t h e most f r e q u e n t l e t t e r s a r e t h e l e a s t l e g i b l e . The h i g h l y f r e q u e n t x-height l e t t e r s a, c , e , 0 , and 2 w e r e p o o r l y r e c o g n i z e d i n b o t h s t u d i e s . The s i m i l a r s i z e and o v e r a l l s h a p e of t h e s e l e t t e r s c a u s e them t o be c o n f u s a b l e a n d , t h e r e f o r e , p o o r l y l e g i b l e . C a t t e l l ' s r e s e a r c h ( 1 8 8 5 ) , a s w e l l a s more

CHAPTER 2

12

Table 2 . 1

Letter a b

Rank o r d e r o f d i s t i n c t i v e n e s s o f l o w e r c a s e a c c o r d i n g t o C a t t e l l ( 1 8 8 5 ) and i n t h e study.

Cattell 19 6

C

25

d e f 9 h i 1 k 1

1 22 17 24 5

m

23 11 2 10 3

Present Study

letters present

Present Letter

Ca t t e l l 18

Study

22

n

1 19 9 23

0

16

P 4 r

I

2

8

18

S

4 15 26

4

t

6 26 20 7 15 11

U

12 9

V

13

W

8

X

20 21 14

Y z

17

24

12 25 21 14 16 10

3 5 13

r e c e n t s t u d i e s by Bouma ( 1 9 7 1 ) and o u r s e l v e s , found t h a t t h e s l i m l e t t e r s g, &, 1,I,r , and t were s i m i l a r l y c o n f u s e d f o r one a n o t h e r l e a d i n g t o r e l a t i v e l y poor r e c o g n i t i o n . Finally, C a t t e l l observed t h a t l e g i b i l i t y i s h i g h l y c o r r e l a t e d with o v e r a l l l e t t e r s i z e ; contemporary s t u d i e s a l s o s u p p o r t t h i s observation. T i n k e r ( 1 9 6 5 ) a l s o n o t e d a g r e e m e n t among s t u d i e s of l e t t e r H e r e p o r t e d c o r r e l a t i o n s between .48 and .88 legibility. a c r o s s s t u d i e s u s i n g , q v a r i e t y of measurement t e c h n i q u e s and were typefaces. For i n s t a n c e , t h e l e t t e r s 4, m, 2 , g , and c o n s i s t e n t l y found t o be h i g h l y l e g i b l e w h e r e a s c , e , I,1, and n were p o o r l y l e g i b l e . Tinker concluded t h a t o v e r a l l s i z e , s i m p l i c i t y o f o u t l i n e , and t h e amount of w h i t e s p a c e e n c l o s e d by a l e t t e r a r e i m p o r t a n t d e t e r m i n a n t s o f l e g i b i l i t y . We w i l l p r o v i d e a more d e t a i l e d a n a l y s i s of l e t t e r l e g i b i l i t y and l e t t e r confusions l a t e r in t h i s chapter. Another common o b s e r v a t i o n i n e a r l y r e s e a r c h was t h a t t e x t p r i n t e d i n u p p e r c a s e l e t t e r s i s inore d i f f i c u l t t o r e a d t h a n i t s lowercase e q u i v a l e n t . Lowercase p r i n t may be more f a m i l i a r than uppercase because of differences i n f r e q u e n c y of occurrence. However, as Spencer (1969) points out, proportionately-spaced printed t e x t in c a p i t a l s occupies about 5 0 % more space than it does i n lowercase. ( U p p e r c a s e and

w

VISUAL INFORMATION I N R E A D I N G

13

l o w e r c a s e o c c u p y t h e same a m o u n t o f s p a c e i n t y p e w r i t t e n t e x t , a s i n t h e p r e s e n t m o n o g r a p h ) . The r e a d e r m u s t m a i n t a i n a l a r g e r span of apprehension i n terms of v i s u a l a n g l e i n o r d e r t o r e a d u p p e r c a s e t e x t a t t h e same r a t e a s l o w e r c a s e . G i v e n t h a t a c u i t y f a l l s off dramatically with e x t e n t i n t o t h e peripheral vision, it is n o t s u r p r i s i n g t h a t lowercase t e x t w i l l show a n a d v a n t a g e . I t would b e i n t e r e s t i n g t o compare up p er and l o w e r c a s e t e x t when t h e s i z e o f t h e l e t t e r s is a d j u s t e d t o e q u a t e f o r v i s u a l a n g l e . However, p e r f o r m a n c e may s t i l l be a t a d i s a d v a n t a g e w i t h u p p e r c a s e s i n c e on t h e a v e r a g e , t h e l a r g e r l e t t e r s w i l l b e c l o s e r t o g e t h e r an d a l l o w f o r m o r e lateral interference (the mutual degradation of the p e r c e p t i b i l i t y of a d j a c e n t l e t t e r s because of t h e proximity of t h e i r c o n t o u r s ) . The s i m p l e s t e x p l a n a t i o n is t h a t l o w e r c a s e l e t t e r s may b e s i m p l y more p e r c e p t i b l e t h a n u p p e r c a s e . J a v a 1 ( c i t e d i n S p e n c e r , 1 9 6 9 ) showed t h a t r e a d i n g i s much e a s i e r when t h e t o p h a l f , r a t h e r t h a n t h e b o t t o m h a l f , o f a l i n e of words is exposed. I t is n o t c l e a r w h e r e t h e v e r t i c a l c e n t e r was d e f i n e d , b u t w e m i g h t a s s u m e t h a t i t was i n t h e m i d d l e o f a n x - h e i g h t l e t t e r . I t would b e v a l u a b l e t o d e f i n e t h e p e r c e p t u a l m i d d l e , i . e . , t h e p o i n t a t which r e a d i n g t h e t o p a line of p r i n t is e q u a l l y and b o t t o m p o r t i o n s of e a s y . C o n s i s t e n t w i t h J a v a l ' s f i n d i n g s , Messmer (cited in Huey, 1 9 0 8 / 1 9 6 8 ) c o n c l u d e d t h a t a s c e n d i n g l e t t e r s ( e . g . , b, h) a r e " d o m i n a n t " a n d c o n t r i b u t e more t o word r e c o g n i t i o n t h a n x-height (e.g., a , 5 ) o r d e s c e n d i n g ( e . g . , g, E) l e t t e r s . Z e i t l e r ( c i t e d i n Woodworth, 1 9 3 8 ) a l s o f o u n d t h a t i n s h o r t p r e s e n t a t i o n s , a s c e n d i n g and d e s c e n d i n g l e t t e r s were more l i k e l y t o b e p e r c e i v e d ( a l s o see Huey, 1 9 0 8 / 1 9 6 8 , p p . 79-87). Javal's i d e a was t h a t a s c e n d i n g l e t t e r s a r e more e a s i l y p e r c e i v e d b e c a u s e t h e e y e t e n d s t o f i x a t e a b o v e t h e m i d d l e of t h e l i n e of p r i n t . Huey ( 1 9 0 8 / 1 9 6 8 p . 99) r e j e c t e d t h i s p r o p o s a l by c i t i . i g some s t a t i s t i c s s h o w i n g t h a t a s c e n d i n g l e t t e r s a r e much m o r e f r e q u e n t t h a n d e s c e n d i n g l e t t e r s , an d therefore, a word i s s i m p l y l i k e l y t o h a v e more i n f o r m a t i o n above t h a n below t h e m i d d l e of a l i n e o f p r i n t .

FEATURE ANALYSIS Consistent with psychologists have c h a r a c t e r i s t i c s of t h e and word p e r c e p t i o n . physical f e a t u r e s of

the tradition of psychophysics, been concerned with the visual stimulus that are functional in l e t t e r The g o a l o f t h i s work i s t o r e l a t e t h e l e t t e r s and words t o t h e i r p e r c e p t u a l

CHAPTER 2

recognition. The e a r l y w o r k e r s i n t h i s a r e a i m p l i c i t l y assumed t h a t l e t t e r s were t h e s m a l l e s t u n i t s o f v i s i b l e a n a l y s i s . In t h i s view, l e t t e r s a r e i n d i v i s i b l e u n i t s t h a t can n o t be analyzed f u r t h e r t o p r o v i d e a d e s c r i p t i o n of t h e r e l a t i o n s h i p among d i f f e r e n t l e t t e r s . I n t o d a y ' s t e r m i n o l o g y , t h i s view would c o r r e s p o n d t o a t e m p l a t e v i e w o f l e t t e r r e c o g n i t i o n . I d e a l l y , t h e r e a d e r would h a v e a t e m p l a t e c o r r e s p o n d i n g t o e a c h o f t h e l e t t e r s i n t h e l a n g u a g e and p e r c e p t u a l r e c o g n i t i o n would i n v o l v e f i n d i n g t h e b e s t match between t h e v i s u a l i n f o r m a t i o n i n t h e l e t t e r and t h e t e m p l a t e i n memory. Opposing t h e v i e w o f l e t t e r s a s i n d i v i s i b l e u n i t s i s t h e i d e a o f l e t t e r s h a v i n g a number of d i s t i n c t i v e f e a t u r e s . T h i s i d e a was g e n e r a t e d by work on t h e l i n g u i s t i c d e s c r i p t i o n o f s p e e c h s o u n d s a b o u t 3 0 y e a r s ago ( J a k o b s o n , F a n t , & H a l l e , 1 9 6 1 ) . Many s t r u c t u r a l l i n g u i s t s a t t h a t t i m e t r e a t e d phonemes a s t h e s m a l l e s t u n i t s of speech. I f phoneme u n i t s a r e i n d i v i s i b l e , then t h e physical or perceptual r e l a t i o n s h i p between two phonemes is n o t of c e n t r a l i n t e r e s t . J a k o b s o n e t al. c h a l l e n g e d t h i s p o i n t o f view by t r e a t i n g phonemes a s A relatively c o n s i s t i n g of a b u n d l e of d i s t i n c t i v e f e a t u r e s . s m a l l number of d i s t i n c t i v e f e a t u r e s c h a r a c t e r i z e d e a c h phoneme (1961) were of t h e l a n g u a g e . As a n e x a m p l e , J a k o b s o n e t a l . a b l e t o u s e j u s t n i n e f e a t u r e s t o d i s t i n g u i s h 28 phonemes i n E n g l i s h . The i d e a of d i s t i n c t i v e f e a t u r e a n a l y s i s a l s o p r o v e d productive in developing p a t t e r n r e c o g n i t i o n by machine. S e l f r i d g e and N e i s s e r ( 1 9 6 0 ) reviewed t e m p l a t e m a t c h i n g schemes and f e a t u r e analysis schemes for the r e c o g n i t i o n of l e t t e r s . These d e v e l o p m e n t s i n l i n g u i s t i c s and a r t i f i c i a l i n t e l l i g e n c e i n f l u e n c e d t h e d e v e l o p m e n t of f e a t u r e models of t h e v i s i b l e c h a r a c t e r i s t i c s of l e t t e r s .

LETTER FEATURES

A v a l u a b l e t e c h n i q u e f o r t h e s t u d y of t h e v i s u a l f e a t u r e s A of l e t t e r s i n v o l v e s t h e g e n e r a t i o n of c o n f u s i o n m a t r i c e s . c o n f u s i o n m a t r i x i n d i c a t e s what l e t t e r s w i l l be s e e n a s o t h e r l e t t e r s when e r r o r s a r e made. To i n d u c e e r r o r s , e i t h e r t h e v i s u a l i n p u t from t h e l e t t e r m u s t be d e g r a d e d o r t h e p r o c e s s i n g time a v a i l a b l e f o r r e c o g n i t i o n o f t h a t l e t t e r m u s t be l i m i t e d . To d e g r a d e l e t t e r s , t h e y h a v e been p r e s e n t e d a t r e l a t i v e l y l a r g e d i s t a n c e s o r i n p e r i p h e r a l v i s i o n . P r o c e s s i n g time i s not l i m i t e d b u t f e a t u r a l information is degraded. To l i m i t p r o c e s s i n g t i m e , l e t t e r s h a v e been p r e s e n t e d f o r a s h o r t d u r a t i o n a t a good f i g u r e - g r o u n d c o n t r a s t b u t c l o s e l y f o l l o w e d


15

by a masking s t i m u l u s t h a t s e r v e s t o h a l t p r o c e s s i n g . The assumption i n l i m i t i n g p r o c e s s i n g t i m e is t h a t t h e r e a d e r m a k e s a n e r r o r b e c a u s e o f i n s u f f i c i e n t time t o p r o c e s s c o m p l e t e l y t h e f e a t u r a l i n f o r m a t i o n . Of c o u r s e , i t i s i m p o r t a n t t o a n a l y z e c o n f u s i o n m a t r i c i e s g e n e r a t e d from b o t h t h e s e methods and t o d e t e r m i n e whether t h e y g i v e s i m i l a r r e s u l t s . Prior t o Bouma's (1971) study, most c o n t e m p o r a r y experiments s t u d i e d t h e c o n f u s i o n s of uppercase l e t t e r s ( e . g . , G i b s o n , O s s e r , S c h i f f , & S m i t h , 1 9 6 3 ; Townsend, 1 9 7 1 ) . Bouma u t i l i z e d l o w e r c a s e l e t t e r s of t h e IBM C o u r i e r 1 0 t y p e f a c e shown Bouma p r e s e n t e d t h e l e t t e r s a t a r e l a t i v e l y i n Figure 2.1. l a r g e r e a d i n g d i s t a n c e i n one s t u d y and i n p e r i p h e r a l v i s i o n i n a n o t h e r . The c o n f u s i o n s were v e r y s y s t e m a t i c and a l l o w e d Bouma t o a s s i g n t h e l e t t e r s t o g r o u p s o f l e t t e r s t h a t were c o n f u s a b l e w i t h i n a g r o u p b u t n o t among g r o u p s . The c o n f u s i o n s among l e t t e r s were p r i m a r i l y d e p e n d e n t upon o v e r a l l l e t t e r s h a p e and size. Many o f t h e r e c o g n i t i o n c o n f u s i o n s c o u l d be d e s c r i b e d by j u s t t h r e e c l a s s e s of l e t t e r s : s h o r t or x -h e ig h t l e t t e r s , and descending letters ascending letters (ascenders), (descenders) Given an x - h e i g h t l e t t e r , a r e c o g n i t i o n conf u s i o n u s u a l l y r e s u l t e d from a n o t h e r x - h e i g h t l e t t e r and s o on. The x - h e i g h t l e t t e r s and a s c e n d e r s c a n a l s o b e b r o k e n down i n t o smaller groups a s i n d i c a t e d i n Table 2.2. Bouma a r g u e s t h a t o v e r a l l l e t t e r s h a p e is a n i m p o r t a n t d e t e r m i n a n t o f r e c o g n i t i o n c o n f u s i o n s and i n t r o d u c e s t h e c o n c e p t of e n v e l o p e . The envelope of a l e t t e r i s t h e s m a l l e s t polygon s u r r o u n d i n g a l e t t e r without indentation. For e x a m p l e , t h e e n v e l o p e f o r c would be c i r c u l a r , w h e r e a s would be e n c l o s e d by a n i n v e r t e d

.

Figure 2.1

a

c

e

m

o

r

s

u

v

w

x

z

b

d

f

h

i

k

l

t

n

Lowercase l e t t e r s o f t h e IBM C o u r i e r 1 0 t y p e f a c e used by Bouma ( 1 9 7 1 ) .

16

Table 2.2

CHAPTER 2

The s e v e n g r o u p s o f c o n f u s a b l e l e t t e r s of t h e C o u r i e r 1 0 t y p e f a c e ( a f t e r Bouma, 1 9 7 1 ) . 1. 2. 3.

4. 5.

6. 7.

a e n r d t g

s o m v h i p

z c u u k l j

IBM

x

b f y q

triangle. T h e s e e n v e l o p e s o f l e t t e r s a c c o u n t f o r some of t h e A s a n e x a m p l e , t h e g r o u p of confusable confusion e r r o r s . l e t t e r s (a, 2 , z, z) have r o u g h l y r e c t a n g u l a r e n v e l o p e s w i t h inner p a r t s . I n o r d e r t o p r o v i d e an independent a s s e s s m e n t of t h e f e a t u r a l i n f o r m a t i o n t h a t i s f u n c t i o n a l i n t h e r e c o g n i t i o n of l o w e r c a s e l e t t e r s , we c a r r i e d out a l e t t e r recognition experiment. F i g u r e 2 . 2 p r e s e n t s a photograph of t h e l e t t e r s a s t h e y a p p e a r e d i n t h e e x p e r i m e n t . A s i n g l e l e t t e r was p r e s e n t e d on e a c h t r i a l a t a r e l a t i v e l y dim i n t e n s i t y t o k e e p o v e r a l l

0123456789 :

;

?

ABCDEFGHIJKLMNO PQRSTUVWXYZ

abcdefghijklmno

pqrstuvwxyz Figure 2.2

The s e t o f c h a r a c t e r s c u r r e n t l y b e i n g used i n o u r laboratory. The c h a r a c t e r s a r e p l o t t e d a s p o i n t s is on an o s c i l l o s c o p e and t h e a v e r a g e c h a r a c t e r composed o f a p p r o x i m a t e l y 35 p o i n t s .

VISUAL INFORMATION I N READING

17

a c c u r a c y a t a b o u t 5 0 % . The t e s t l e t t e r was p r e s e n t e d a t t h e f i x a t i o n p o i n t f o r a s h o r t d u r a t i o n and no masking s t i m u l u s was presented. Three s u b j e c t s contributed a t o t a l of 296 o b s e r v a t i o n s f o r e a c h o f t h e 26 l e t t e r s o f t h e a l p h a b e t . T a b l e 2.3 p r e s e n t s t h e o v e r a l l a c c u r a c y f o r e a c h o f t h e 26 l e t t e r s , t h e f a l s e a l a r m r a t e s , t h e d ' v a l u e s , and c o n f u s i o n r e s p o n s e s t h a t o c c u r r e d more t h a n 5% o f t h e t i m e t o a g i v e n t e s t l e t t e r . One p o s s i b l e l i m i t a t i o n w i t h t h e s e d a t a and o t h e r s t u d i e s of t h i s nature is t h a t t h e l e t t e r s d i f f e r i n o v e r a l l accuracy, and t h e r e f o r e , t h e r e is n o t an e q u a l o p p o r t u n i t y f o r c o n f u s i o n s f o r e a c h o f t h e l e t t e r s . On t h e o t h e r h a n d , i t m i g h t be a r g u e d t h a t t h e o v e r a l l a c c u r a c y o f a g i v e n a l t e r n a t i v e may r e f l e c t That is t o s a y , how e a s i l y i t i s c o n f u s e d w i t h o t h e r l e t t e r s . a l e t t e r c o m p l e t e l y d i s s i m i l a r from t h e o t h e r l e t t e r s would g i v e good p e r f o r m a n c e s i n c e i t w i l l n o t b e c o n f u s e d f o r a n y o f the alternatives. R e g a r d l e s s of which i n t e r p r e t a t i o n i s more i t m i g h t be w o r t h w h i l e t o r e p e a t t h e e x p e r i m e n t reasonable, while a d j u s t i n g t h e i n t e n s i t y i n d i v i d u a l l y f o r each l e t t e r t o keep i t s performance a t 50% c o r r e c t . The p e r c e n t a g e c o r r e c t i d e n t i f i c a t i o n f o r e a c h o f t h e 26 l e t t e r s o f t h e a l p h a b e t i n T a b l e 2.3 shows t h a t r e c o g n i t i o n a c c u r a c y r a n g e d w i d e l y . T h i s r e s u l t may r e p r e s e n t a v i s u a l e f f e c t O K a d e c i s i o n e f f e c t . Some l e t t e r s may p r o v i d e more v i s u a l f e a t u r a l i n f o r m a t i o n t h a n o t h e r l e t t e r s u n d e r t h e same stimulus conditions. Alternatively, observers may d e r i v e e q u i v a l e n t amounts o f f e a t u r a l i n f o r m a t i o n from a l l l e t t e r s b u t may h a v e d e c i s i o n b i a s e s i n t h e i n t e r p r e t a t i o n of t h e f e a t u r a l information. A s a n example, o b s e r v e r s might be biased t o i n t e r p r e t t h e f e a t u r a l i n f o r m a t i o n i n terms of l e t t e r s t h a t o c c u r more f r e q u e n t l y in the language. The d e c i s i o n i n t e r p r e t a t i o n , however, appears t o be i n c o n s i s t e n t with t h e results. For e x a m p l e , t h e i n f r e q u e n t l e t t e r s 5 , y , and a v e r a g e d a b o u t 65% c o r r e c t , w h e r e a s t h e f r e q u e n t l e t t e r s e , g, 0 , and 2 a v e r a g e d a b o u t 35% c o r r e c t . I n c o n t r a s t t o what would be e x p e c t e d from a f r e q u e n c y b i a s , t h e s e l e a s t f r e q u e n t l e t t e r s are recognized much better than the more frequent l e t t e r s . This analysis provides support for the idea t h a t d i f f e r e n c e s i n accuracy a r e due t o d i f f e r e n c e s i n t h e f e a t u r a l i n f o r m a t i o n of t h e l e t t e r s . A more d i r e c t m e a s u r e of v i s u a l r e s o l u t i o n i s t o t a k e a 4 ' m e a s u r e a s p r o p o s e d by t h e t h e o r y o f & Swets, 1966; Massaro & signal detectability (Green Schmuller,. 1 9 7 5 ) . T a b l e 2.3 shows t h a t t h e s e d ' v a l u e s correlate rather highly with the percentage correct v a l u e s . Given t h e a s s u m p t i o n t h a t t h e d' v a l u e s a r e n o t i n f l u e n c e d by any d i f f e r e n c e s i n d e c i s i o n b i a s e s , t h e r e s u l t s

z

18

CHAPTER 2

T a b l e 2.3

Letter

a b C

d e f 4 h i j k 1

m n 0

P 9

r S

t U V W

X

Y 7.

P r o p o r t i o n o f times a letter was r e c o g n i z e d correctly (Hit) a n d was g i v e n a s a n i n c o r r e c t r e s p o n s e t o o t h e r l e t t e r s ( F a l s e A l a r m ) ; t h e d' a l u e ; and t h e confusion responses g r e a t e r t h a n 5% (from present study).

Hit

.372 .743 .449 .639 .365 .456 .703 .662 .277 .412 .655 .530 .628 .497 .331 .730 .649 .591 .324 .382 .554 .520 .632 .730 .686 .571

F a l s e Alarm .015 .020 .016 .011 .017 .0 20 .022 .020 .023 .017 .014 .022 .010 .013 .014 .016 ,010 .023 .010 . 0 20 .010 .015 .010 .010 .015 .010

A'

C o n f u s i o n s Greater t h a n 5%

1.85 2.72 2.05 2.64 1.79 1.94 2.56 2.46 1.42 1.92 2.61 2.10 2.66 2.24 1.78 2.78 2.71 2.24 1.87 1.76 2.46 2.16 2.66 2.94 2.67 2.51

locate the differences i n letter recognition a t a visual stage of p r o c e s s i n g . T a b l e 2.3 a l s o p r o v i d e s a n i n d e x o f t h e l e t t e r s which are confused w i t h o t h e r l e t t e r s i n t h e t a s k . For each l e t t e r , a l l c o n f u s i o n s g i v e n f o r t h a t l e t t e r g r e a t e r t h a n 5% o f t h e t i m e are presented. As a n e x a m p l e , g i v e n t h e s t i m u l u s a, s u b j e c t s r e s p o n d e d 1 4 % o f t h e time w i t h t h e a l t e r n a t i v e g a n d 7 % o f t h e time w i t h a l t e r n a t i v e g. T h i s m e a n s t h a t t h e l e t t e r a is o f t e n


19

i n t e r p r e t e d a s e . The c o n f u s i o n s a p p e a r t o b e r e l a t i v e l y s y s t e m a t i c and t h e r e f o r e s u g g e s t w h i c h f e a t u r e s a r e f u n c t i o n a l T a b l e 2.4 p r o v i d e s a n a l o g o u s d a t a from in letter recognition. t h e p e r i p h e r a l - v i e w i n g e x p e r i m e n t c a r r i e d o u t b y Bouma o n t h e IBM C o u r i e r 10 typeface. The c o n f u s i o n s w i l l b e u t i l i z e d i n o u r l a t e r work when t h e r e l a t i v e s i m i l a r i t y b e t w e e n l e t t e r s beco m es a n i m p o r t a n t q u e s t i o n i n o u r e x p e r i m e n t s . The l e t t e r c o n f u s i o n s s u g g e s t t h a t o v e r a l l l e t t e r s h a p e i n f o r m a t i o n may b e o b t a i n e d b e f o r e c o m p l e t e l e t t e r p e r c e p t i o n ( r e s o l u t i o n ) . For example, 48% o f t h e e r r o r r e s p o n s e s t o t h e s t i m u l u s 2 were and 0 ; t h i s i n d i c a t e s t h a t s u b j e c t s saw a c i r c u l a r s h a p e o n many o f t h e t r i a l s b u t d i d n o t know w h e t h e r t h e l e t t e r was 2 , e , o r 0 . T h i s r e s u l t m i g h t b e i n t e r p r e t e d t o mean t h a t t h e o v e r a l l e n v e l o p e o f a l e t t e r i s r e s o l v e d b e f o r e d e t a i l s o f i t s component f e a t u r e s . I n d e p e n d e n t l y o f w h e t h e r a general t h e wh o l e i s g r e a t e r t h a n t h e s u m o f i t s p a r t s , impression of t h e whole ( a l t h o u g h ambiguous) is s e e n b e f o r e a l l of t h e p a r t s . T h a t a l e t t e r ' s e n v e l o p e ( n o pun i n t e n d e d ) be co m es a v a i l a b l e b e f o r e i t s d e t a i l s i s a l s o c o n s i s t e n t w i t h fourier-analysis s t u d i e s . T h e r e is e v i d e n c e t h a t i n f o r m a t i o n g i v e n by l o w s p a t i a l f r e q u e n c i e s i s p r o c e s s e d f a s t e r t h a n h i g h & Ganz, 1976; s p a t i a l frequency information (Breitmeyer Broadbent, 1 9 7 7 ) . Accordingly, low s p a t i a l f r e q u e n c i e s p r o v i d e information about o v e r a l l shape whereas high frequency information reduces uncertainty about l e t t e r d e t a i l . Either time o r a r e d u c e d f igure-ground contrast limited processing could allow envelope resolution without corresponding resolution of letter d e t a i l . I n terms o f t h e p r e s e n t a n a l y s i s , t h e r e a d e r w i l l have t o d e c i d e which l e t t e r b e s t f i t s t h e perceived b u t fuzzy envelope. For ex a m pl e, r e c o g n i t i o n o f a c i r c u l a r e n v e l o p e w i t h o u t f u r t h e r d e t a i l would b e s u f f i c i e n t t o l i m i t t h e a l t e r n a t i v e s t o t h e t h r e e l e t t e r s 2 , g , a n d 0. Given t h a t our primary m o t i v a t i o n is t o s t u d y t h e i n t e r a c t i o n of lower-level v i s u a l information with higher-order kn o wl ed g e i n l e t t e r r e c o g n i t i o n , we a r e n o t d i r e c t l y c o n c e r n e d w i t h wh i ch l e t t e r features are utilized i n perceptual recognition. T h e r e a r e now s u f f i c i e n t d a t a c o n s i s t e n t w i t h t h e i d e a t h a t l e t t e r r e c o g n i t i o n i s m e d i a t e d by f e a t u r e s ( M a s s a r o & Schmuller, 1 9 7 5 ) . F e a t u r e s a r e n o t l i m i t e d t o s m a l l co m p o n en t p r o p e r t i e s b u t c a n b e r e l a t i v e l y complex r e l a t i o n a l p r o p e r t i e s s u c h a s t h e o v e r a l l c i r c u l a r e n v e l o p e o f t h e l e t t e r s 5, g , a n d 0. Additionally, i n c o n t r a s t t o t h e common a s s u m p t i o n t h a t f e a t u r e s a r e d e t e c t e d i n a n all-or-none manner, w e p r e f e r t o view t h e f e a t u r e d e t e c t i o n p r o c e s s a s continuous. Visible f e a t u r e s may b e f u z z y so t h a t recognition consists of

e

20

CHAPTER 2

T a b l e 2.4

Letter H i t

a b C

d

e f g h

i j k 1

m n 0

P 9

r S

t U

V W X

Y Z

.620 .620 .190 .830 .340 .810 .310 .800 .690 .820 .510 .260 .790 .560 .570 .840 .740 .550 .100 .590 .560 .720 .700 .320 .570 .120

P r o p o r t i o n of times a letter was r e c o g n i z e d correctly ( H i t ) a n d was g i v e n a s an i n c o r r e c t response to other letters ( F a l s e Alarm); t h e c o r r e s p o n d i n g d' v a l u e ; and t h e c o n f u s i o n r e s p o n s e s g r e a t e r t h a n 5% ( f r o m Bouma, 1 9 7 1 ) .

F a l s e Alarm .053 .024 .006 .019 .045 .013 .018 .028 .035 .008 .008 .007 .028 .026 .017 .017 .019 .015 .009 .0 1 3 .018 .016 .014 .003 .003 .004

d' 1.93 2.29 1.62 3.03 1.29 3.11 1.60 2.76 2.31 3.33 2.46 1.81 2.72 2.10 2.30 3.12 2.71 2.31 1.08 2.46 2.26 2.73 2.73 2.25 2.95 1.46

C o n f u s i o n s Greater t h a n 5%

VISUAL INFORMATION I N READING

21

a s c e r t a i n i n g t h e d e g r e e t o which t h a t f e a t u r e is p r e s e n t o r a b s e n t i n t h e s t i m u l u s . Oden and Massaro ( 1 9 7 8 ) have d e v e l o p e d a model of s p e e c h p e r c e p t i o n b a s e d on t h e i d e a of c o n t i n u o u s acoustic features. A s i m i l a r a n a l y s i s would seem t o b e a v a l u a b l e c o n t r i b u t i o n i n l e t t e r r e c o g n i t i o n , a l t h o u g h beyond t h e s c o p e of t h e p r e s e n t r e s e a r c h . For i n t e r e s t e d r e a d e r s , Oden ( 1 9 7 9 ) i n i t i a t e d a n e m p i r i c a l and t h e o r e t i c a l s t u d y o f f u z z y f e a t u r a l i n f o r m a t i o n i n l e t t e r s , and Massaro ( 1 9 7 9 a ) q u a n t i f i e d a model t o a c c o u n t f o r how c o n t i n u o u s f e a t u r a l i n f o r m a t i o n of a l e t t e r is i n t e g r a t e d w i t h o r t h o g r a p h i c c o n t e x t in l e t t e r recognition.


3

Orthographic Structure

I n t h i s c h a p t e r we d e s c r i b e t h e f u n d a m e n t a l p r o p e r t i e s o f o r t h o g r a p h i c s t r u c t u r e and s p e c u l a t e on how t h e s e p r o p e r t i e s m i g h t f a c i l i t a t e l e t t e r and word r e c o g n i t i o n . The g o a l of t h i s d i s c u s s i o n is t o d e r i v e d i f f e r e n t m e t r i c s f o r s c a l i n g t h e o r t h o g r a p h i c s t r u c t u r e o f l e t t e r s t r i n g s b a s e d upon d i f f e r e n t a s s u m p t i o n s a b o u t how o r t h o g r a p h i c s t r u c t u r e c o n t r i b u t e s t o recognition processes. The e x p e r i m e n t s p r e s e n t e d i n C h a p t e r 4 a t t e m p t t o e v a l u a t e t h e p s y c h o l o g i c a l r e a l i t y of s e v e r a l of t h e s e measures. Central t o the discussion of t h i s chapter is the assumption t h a t s k i l l e d r e a d e r s d e r i v e information about l e g a l o c c u r r e n c e s of l e t t e r s o r l e t t e r s e q u e n c e s from r e p e a t e d e x p o s u r e s t o p r i n t e d words and that t h e y employ t h i s i n f o r m a t i o n t o f a c i l i t a t e word r e c o g n i t i o n i n normal r e a d i n g t a s k s . Our c o n c e r n h e r e is w i t h b o t h t h e d e s c r i p t i o n of t h e abstracted i n f o r m a t i o n and i t s u t i l i z a t i o n i n t h e r e c o g n i t i o n process. I n t h e d i s c u s s i o n which f o l l o w s w e c o n c e n t r a t e on two broad c a t e g o r i e s of orthographic structure: s t a t i s t i c a l redundancy and rule-governed regularity. Statistical r e d u n d a n c y a p p l i e s t o t h o s e m e a s u r e s which c a n b e d e r i v e d s o l e l y from t h e f r e q u e n c y w i t h which l e t t e r s , l e t t e r s e q u e n c e s , and words o c c u r i n n a t u r a l t e x t s . Such m e a s u r e s m i g h t b e b a s e d upon t y p e o r t o k e n c o u n t s . The m e a s u r e s m i g h t a p p l y t o l e t t e r s , l e t t e r s e q u e n c e s , o r t o any c l a s s i f i c a t i o n of t h e s e e n t i t i e s (e.g., vowel, c o n s o n a n t ) . Rule-governed regularity a p p l i e s t o t h o s e p r o p e r t i e s o f l e t t e r s and l e t t e r s e q u e n c e s which c a n be generalized from e i t h e r the phonological The c o n s t r a i n t s of E n g l i s h words o r t h e s c r i b a l c o n v e n t i o n s . l a t t e r c o n t r o l t h e s e l e c t i o n of l e t t e r s f o r e i t h e r r e p r e s e n t i n g s o u n d s o r marking g r a p h e m i c , g r a p h o t a c t i c , o r m o r p h o l o g i c a l

24

CHAPTER 3

functio:is. Rule-governed r e g u l a r i t y u s u a l l y s p e c i f i e s a l e t t e r s t r i n g a s regular o r i r r e g u l a r . I n a d d i t i o n , through t h e of rules for generating legal (i.e., specification English-like) l e t t e r s t r i n g s , l e v e l s of r e g u l a r i t y c a n be defined.

STATISTICAL REDUNDANCY O r d e r e d a p p r o x i m a t i o n s t o E n g l i s h , b a s e d on a l g o r i t h m s p r o p o s e d by Shannon ( 1 9 4 8 ) , were t h e f i r s t d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e u t i l i z e d by p s y c h o l o g i s t s . Shannon ( 1 9 4 8 ) c r e a t e d a z e r o - o r d e r a p p r o x i m a t i o n t o E n g l i s h by d r a w i n g l e t t e r s w i t h r e p l a c e m e n t from a p o o l o f 27 u n w e i g h t e d symbols--the 26 l e t t e r s o f t h e a l p h a b e t p l u s a s p a c e . (In this a s i n most o t h e r s e q u e n t i a l g e n e r a t i o n t e c h n i q u e s , a n i n i t i a l I f t h i s same p r o c e d u r e is employed s p a c e symbol i s assumed.) w i t h symbols t h a t a r e w e i g h t e d a c c o r d i n g t o t h e i r f r e q u e n c i e s of occurrence i n t e x t s , f i r s t - o r d e r ap p r o x im a tio n s r e s u l t . An n - g o r d e r a p p r o x i m a t i o n i s p r o d u c e d by f i r s t s e l e c t i n g a l e t t e r s t r i n g of l e n g t h n-1. T h i s f o r m s t h e b e g i n n i n g p a r t o f t h e new s t r i n g . The t e x t i s t h e n s c a n n e d f o r t h e f i r s t o c c u r r e n c e o f t h i s i n i t i a l s t r i n g . When f o u n d , t h e n e x t l e t t e r a f t e r t h e l e t t e r s t r i n g s e q u e n c e is added t o t h e s t r i n g b e i n g g e n e r a t e d , and a n e w s e a r c h s t r i n g i s c o n s t r u c t e d by d r o p p i n g t h e f i r s t l e t t e r of t h e l a s t s e a r c h s t r i n g and a d d i n g t h e T h i s p r o c e d u r e is t h e n r e p e a t e d u n t i l a l e t t e r j u s t located. space occurs or a d e s i r e d l e n g t h reached. M i l l e r , B r u n e r , and Postman ( 1 9 5 4 ) used t h i s t e c h n i q u e t o g e n e r a t e e i g h t - l e t t e r pseudowords f o r a full-report task. Their fourth-order items like mossiant, oneticul, approximations included all quite English-like. Wallach p r e v e r a l , and f a v o r i a l , ( 1 9 6 3 ) , on t h e o t h e r h a n d , t r u n c a t e d two l e t t e r s from e a c h s t r i n g used by Miller e t a l . t h u s o c c a s i o n a l l y p r o d u c i n g a non-English s p e l l i n g ( e . g . , m o s s i a , l o r i a i ) . Although M i l l e r e t a l . ( 1 9 5 4 ) were p r i m a r i l y c o n c e r n e d w i t h i n f o r m a t i o n t h e o r y , 1973; l a t e r experimenters ( e . g . , L e f t o n , S p r a g i n s , & Byrnes, Mewhort & B e a l , 1977) h a v e a d v o c a t e d o r d e r e d a p p r o x i m a t i o n s a s psychologically relevant descriptions of orthographic structure A major s h o r t c o m i n g o f o r d e r e d a p p r o x i m a t i o n d e s c r i p t i o n s is t h e i r i n a b i l i t y t o control s t r u c t u r a l v a r i a t i o n s within approximation l e v e l s . Although any l a r g e g r o u p o f s t i m u l i g e n e r a t e d by t h i s t e c h n i q u e w i l l a p p r o x i m a t e t h e f r e q u e n c i e s o f o c c u r r e n c e of E n g l i s h l e t t e r s e q u e n c e s , t h e r e i s no m e t r i c

.

ORTHOGRAPHIC STRUCTURE

25

i n c o r p o r a t e d i n t o t h e m e th o d f o r a s s e s s i n g t h e r e l a t i v e d e g r e e of o r t h o g r a p h i c s t r u c t u r e of s t r i n g s w i t h i n o r d e r c l a s s e s . In Gilmore an d Egeth (1976), for example, zero-order a p p r o x i m a t i o n s t o E n g l i s h were used t o g e n e r a t e what t h e a u t h o r s i n t e n d e d t o be nonwords, which t h e y c o n t r a s t e d w i t h r e a l E n g l i s h words. I f no o t h e r c r i t e r i a were used t o e v a l u a t e t h e 30 s t r i n g s g e n e r a t e d f o r u s e i n t h e i r e x p e r i m e n t s , there was a 1 8 % c h a n c e t h a t a t l e a s t o n e r e a l word o c c u r r e d ( b a s e d o n t h e a s s u m p t i o n o f 1 , 5 0 0 common f o u r - l e t t e r w o r d s i n E n g l i s h ) ; t h e p r o b a b i l i t y t h a t p s e u d o w o r d s o c c u r r e d was c o n s i d e r a b l y higher. A second shortcoming of a s t r i c t p s y c h o l o g i c a l a p p l i c a t i o n of t h i s a p p r o a c h i s i t s s t r i c t r e l i a n c e o n l e f t - t o - r i g h t For e x a m p l e , g e n e r a t i o n of l e t t e r s d u r i n g word r e c o g n i t i o n . six-letter g i v e n thand th-ugh a s p a r t i a l l y p e r c e i v e d s t r i n g s , t h e p r o b a b i l i t i e s of i d e n t i f y i n g t h e t h i r d l e t t e r i n e a c h would b e t h e same i n t h a t o n l y i n f o r m a t i o n t o t h e l e f t b u t n o t t o t h e r i g h t o f any l e t t e r p o s i t i o n is r e l e v a n t . To o v er co m e t h e s e d i f f i c u l t i e s , summed b i g r a m an d t r i g r a m c o u n t s have been proposed a s metrics. Underwood an d S c h u l z ( 1 9 6 8 ) t a b u l a t e d t h e b i g r a m s and t r i g r a m s i n 2 , 0 9 0 w o r d s s a m p l e d f r o m T h o r n d i k e and L o r g e ( 1 9 4 4 ) . S i n c e e a c h s a m p l e word was w e i g h t e d by i t s f r e q u e n c y o f o c c u r r e n c e i n t e x t s , t o k e n - b a s e d b i g r a m a n d t r i g r a m c o u n t s r e s u l t e d . By summing t h e frequencies of a l l t h e bigrams or trigrams within a letter s t r i n g , a f a m i l i a r i t y index can be d e r i v e d . S u ch a p r o c e d u r e was u s e d b y A n i s f e l d ( 1 9 6 4 ) , f o r e x a m p l e , i n r e a n a l y z i n g t h e Gibson, P i c k , O s s e r , and Hammond ( 1 9 6 2 ) s t u d y o f a f u l l r e p o r t of visually-presented letter strings varying in p r o n o u n c e a b i l i t y . According t o A n i s f e l d (1964) , t h e Gibson e t al. r e s u l t s c o u l d b e a c c o u n t e d f o r a s e a s i l y by d i f f e r e n c e s i n summed b i g r a m c o u n t s a s t h e y c o u l d b y t h e s p e l l i n g - t o - s o u n d u n i t s advocated by Gibson e t a l . Gibson ( 1 9 6 4 ) , i n a r e p l y t o Anisfeld ( 1 9 6 4 1 , h o w e v e r , showed t h a t c o r r e l a t i o n s o f summed b i g r a m and summed t r i g r a m c o u n t s w i t h s u b j e c t r e s p o n s e s w e r e lo w and n o n s i g n i f i c a n t . I n a d d i t i o n , Gibson, S h u r c l i f f , and Yonas ( 1 9 7 0 ) f o u n d n e i t h e r summed b i g r a m n o r summed t r i g r a m counts t o be an adequate predictor of recognition s c o r e s f o r unpronounceable and pronounceable l e t t e r s t r i n g s . Gibson e t a l . (1970) d i d n o t provide a f a i r test of the f r e q u e n c y measures, however, b e c a u s e t h e c o u n t s were n o t a d j u s t e d f o r word l e n g t h i n a n y r e a s o n a b l e m a n n e r . Word l e n g t h a l o n e a c c o u n t e d f o r a b o u t 7 0 % of t h e v a r i a n c e i n t h e r e c a l l s c o r e s ; t h e number o f e r r o r s n a t u r a l l y i n c r e a s e d w i t h i n c r e a s e s in the length of the letter string. The s i g n i f i c a n t

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c o r r e l a t i o n o f p r o n o u n c e a b i l i t y c o u l d be d u e t o t h e s i m p l e f a c t t h a t s h o r t e r words a r e more p r o n o u n c e a b l e t h a n l o n g e r words. S u p p o r t i n g t h i s i n t e r p r e t a t i o n , S p r e e n and S c h u l z ( 1 9 6 6 ) f o u n d a n e g a t i v e c o r r e l a t i o n of .83 b e t w e e n word l e n g t h and p r o n o u n c e a b i l i t y f o r 329 common nouns. Therefore, t h e r e s u l t s o f Gibson e t a l . ( 1 9 6 2 , 1970) r e a l l y d o n o t s p e a k t o t h e i s s u e of p r o n o u n c e a b i l i t y v e r s u s o r t h o g r a p h i c s t r u c t u r e of l e t t e r s t r i n g s when s t r i n g l e n g t h i s h e l d c o n s t a n t . The Underwood and S c h u l z ( 1 9 6 0 ) t a b l e s p r o v i d e a means f o r differentiating familiar and unfamiliar strings within a p p r o x i m a t i o n c l a s s e s , b u t s u f f e r from l a c k o f a t t e n t i o n t o A common word l e n g t h o r p o s i t i o n of l e t t e r s w i t h i n a word. s u f f i x l i k e -&would h e a v i l y w e i g h t a t r i g r a m c o u n t f o r a pseudoword w h e t h e r i n i n i t i a l o r f i n a l p o s i t i o n a c c o r d i n g t o t h e s e t a b l e s , y e t i n E n g l i s h words t h i s s e q u e n c e n e v e r o c c u r s is a initially. If letter position within a word p s y c h o l o g i c a l l y r e l e v a n t v a r i a b l e , t h e Underwood and S c h u l z ( 1 9 6 0 ) t a b l e s c o u l d n o t be used f o r e x p l o r i n g t h i s f a c t o r . T h i s s h o r t c o m i n g h a s been overcome, however, in the Mayzner and T r e s s e l t ( 1 9 6 5 ) and Mayzner, T r e s s e l t , and Wolin ( 1 9 6 5 a , 1965b) t a b l e s , which give bigram, t r i g r a m , and t e t r a g r a m c o u n t s by word p o s i t i o n and by word l e n g t h f o r words from t h r e e t o s e v e n c h a r a c t e r s i n l e n g t h . Mayzner and T r e s s e l t ( 1 9 6 5 ) a l s o g i v e s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c i e s , which have been used by Mason ( 1 9 7 5 ) t o e x p l o r e d i f f e r e n c e s between good and poor r e a d e r s i n a r e c o g n i t i o n t a s k . Although Mason (1975) c o n f o u n d s r u l e - g o v e r n e d orthographic s t r u c t u r e with p o s i t i o n a l frequency, a small but s i g n i f i c a n t p o s i t i o n a l f r e q u e n c y e f f e c t r e m a i n s when t h e s e v a r i a b l e s a r e s e p a r a t e d ( M a s s a r o , Venezky, & T a y l o r , 1 9 7 9 ) . The relationships among single-letter positional f r e q u e n c y , b i g r a m p o s i t i o n a l f r e q u e n c y , and t r i g r a m p o s i t i o n a l f r e q u e n c y h a v e o n l y begun t o be e x p l o r e d . McClelland and J o h n s t o n ( 1 9 7 7 ) o b s e r v e d t h a t a c c u r a c y o f r e p o r t of f o u r - l e t t e r i t e m s was s i g n i f i c a n t l y c o r r e l a t e d w i t h summed s i n g l e - l e t t e r p o s i t i o n a l frequency b u t n o t w i t h bigram p o s i t i o n a l f r e q u e n c y . Bouwhuis ( 1 9 7 9 ) found t h a t s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y made a s i g n i f i c a n t c o n t r i b u t i o n t o l e x i c a l d e c i s i o n s a b o u t three-letter items. R e a c t i o n times t o words d e c r e a s e d w i t h i n c r e a s e s i n f r e q u e n c y w h e r e a s r e a c t i o n times t o pseudowords increased. S i m i l a r l y , high s i n g l e - l e t t e r p o s i t i o n a l frequency i n c r e a s e d t h e number of "word" r e s p o n s e s t o b o t h words and pseudowords. These s i g n i f i c a n t c o r r e l a t i o n s were c o n s i d e r a b l y d i m i n i s h e d when b i g r a m p o s i t i o n a l f r e q u e n c y was used a s t h e p r e d i c t o r v a r i a b l e . T h e s e r e s u l t s imply t h a t t h e power o f t h e


27

bigram frequency measure ( s e e Chapter 5 ) w i t h our s i x - l e t t e r i t e m s may n o t g e n e r a l i z e c o m p l e t e l y t o s m a l l e r l e t t e r - s t r i n g lengths. It is p o s s i b l e to generate letter s t r i n g s while i n d e p e n d e n t l y v a r y i n g summed s i n g l e - l e t t e r p o s i t i o n a l - f r e q u e n c y a n d summed b i g r a m p o s i t i o n a l - f r e q u e n c y counts. W i t h some s t r a i n i n g , t h e same c a n b e d o n e f o r summed b i g r a m a n d summed trigram counts. For example, nachim h a s ( a c c o r d i n g t o Mayzner, e t al. 1 9 6 5 b ) l e g a l b i g r a m s b u t no l e g a l t r i g r a m s . Nather, on A legal t h e o t h e r hand, h a s l e g a l b i g r a m s and l e g a l t r i g r a m s . bigram o r a l e g a l t r i g r a m means t h a t t h e s p e l l i n g p a t t e r n o c c u r s w i t h f r e q u e n c i e s a b o v e z e r o i n t h e Mayzner e t a l . tables. T h e Mayzner e t a l . t a b l e s m i g h t b e b a s e d o n t o o s m a l l a sample f o r r e l i a b l e counts. C o n s e q u e n t l y , we h a v e d e v i s e d t a b l e s from t h e Kucera and F r a n c i s ( 1 9 6 7 ) m i l l i o n - w o r d l i s t and h a v e u t i l i z e d them i n t h e p r e s e n t p r o j e c t . The d e s c r i p t i o n o f t h e a n a l y s i s and t h e s i n g l e - l e t t e r and bigram t a b l e s a r e g i v e n i n Appendix 5.2 a n d 5.3. A f u r t h e r i s s u e t h a t n e e d s t o b e c l a r i f i e d is t h e r e l a t i v e importance o f t o k e n measures and t y p e measures. Token c o u n t s r e p r e s e n t a summed o c c u r r e n c e f o r some l e t t e r s e q u e n c e , r e g a r d l e s s o f t h e number o f u n i q u e w o r d s w h i c h c o n t r i b u t e t o t h i s sum. Type c o u n t s , o n t h e o t h e r h a n d , r e p r e s e n t a sum o f t h e unique words i n which a l e t t e r sequence o c c u r s , r e g a r d l e s s of t h e f r e q u e n c i e s o f occurrence of t h e words. In a l l of the e x p e r i m e n t a l work r e p o r t e d s o far t h a t used sequential redundancy m e a s u r e s , t o k e n c o u n t s have been employed. Solso and h i s c o l l e a g u e s ( S o l s o , 1979; S o l s o & K i n g , 1976; S o l s o , B a r b u t o , & J u e l , 1 9 7 9 ; S o l s o , T o p p e r , & Macey, 1 9 7 3 ; T o p p e r , Macey, & S o l s o , 1 9 7 3 ) r e p o r t some t y p e - b a s e d t a b u l a t i o n s b a s e d o n t h e K u c e r a a n d F r a n c i s ( 1 9 6 7 ) word l i s t s b u t no e x p e r i m e n t a l data. However, t h e r e i s no a p r i o r i r e a s o n f o r a s s u m i n g t h a t word t o k e n s h a v e g r e a t e r p s y c h o l o g i c a l r e a l i t y t h a n word t y p e s n o r a r e t h e r e e m p i r i c a l d a t a r e l e v a n t t o t h i s q u e s t i o n . We a d d r e s s t h i s i s s u e i n Chapter 5. T y p e - b a s e d m e a s u r e s c o u l d b e d e r i v e d from a r e p r e s e n t a t i o n of a n i n t e r n a l l e x i c o n , b u t token measures a l s o r e q u i r e t h e W h i l e i t is e x i s t e n c e o f d i s t r i b u t i o n a l i n f o r m a t i o n i n memory. r e a s o n a b l e t o a s s u m e t h a t some f o r m s o f b o t h t o k e n a n d t y p e i n f o r m a t i o n m i g h t h a v e p s y c h o l o g i c a l r e a l i t y , how t h e r e a d e r m i g h t a p p l y r a w t o k e n m e a s u r e s i n word r e c o g n i t i o n i s n o t coinpletely obvious (cf. Savin, 1 9 6 3 ) . However, some i n t e r e s t i n g a p p r o a c h e s t o u s i n g t o k e n m e a s u r e s embedded w i t h i n t y p e m e a s u r e s h a v e b e e n p r o p o s e d b y Solomon a n d P o s t m a n ( 1 9 5 2 ) , S a v i n ( 1 9 6 3 ) , and more r e c e n t l y by Landauer and S t r e e t e r

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(1973). As an example, t h e viab,le a l t e r n a t i v e s could be n a r r o w e d down t o a l l w o r d s c o n s i s t e n t w i t h t h e f e a t u r a l i n f o r m a t i o n and t h e r e a d e r m i g h t c h o o s e t h e m o s t f r e q u e n t word from t h i s s e t . B u t w h a t e v e r a p p l i c a t i o n m i g h t b e shown f o r f r e q u e n c y i n f o r m a t i o n i n word r e c o g n i t i o n , t h e s p e c i f i c r o l e o f t h e s e measures has y e t t o b e determined. I f summed f r e q u e n c y ( t o k e n o r type) is psychologically r e l e v a n t , then t h e u t i l i z a t i o n of a m e a s u r e l i k e b i g r a m f r e q u e n c y would r e q u i r e a m a x i m i z i n g process. Consider the task o f perceiving a f i v e - l e t t e r s t r i n g wh er e t h e v i s u a l i n f o r m a t i o n a l l o w s a n a c c e p t a b l e r e s o l u t i o n o f LlL2-L4L5. Assume t h a t no a l l letters except one, e.g., The u s e o f b i g r a m v i s u a l i n f o r m a t i o n is a v a i l a b l e f o r L 3 . i n f o r m a t i o n r e q u i r e s t h a t L 3 b e s e l e c t e d t o m ax i m i ze t h e sum o f t h e bigram f r e q u e n c i e s o f L 2 L 3 and L 3 L 4 , s e l e c t i n g L 3 from a pool of a l l 26 l e t t e r s . If some v i s u a l information is a v a i l a b l e f o r L 3 , then t h e pool OE a v a i l a b l e l e t t e r s might be r e s t r i c t e d t o t h o s e t h a t were c o m p a t i b l e w i t h t h e a v a i l a b l e i n f o r m a t i o n b u t o t h e r w i s e t h e s t r a t e g y would b e t h e same. For a t r i g r a m s t r a t e g y , a s i m i l a r p r o c e s s c o u l d b e u sed b u t w i t h t h e maximizing o f t h e combined f r e q u e n c i e s f o r L l L 2 L 3 + L 2 L 3 L 4 + L 3 L 4 L 5 . The c o m p l e x i t y o f t h i s s t r a t e g y d o e s n o t n e c e s s a r i l y make i t s p s y c h o l g i c a l r e l e v a n c e s u s p e c t . A p o t e n t i a l d r a w b a c k t o summed s i n g l e - l e t t e r , b i g r a m , an d t r i g r a m p o s i t i o n a l c o u n t s , p a r t i c u l a r l y where token c o u n t s a r e is t h e dominating r o l e played by a s m a l l g r o u p utilized, o f high-frequency words. For t h e f o u r - l e t t e r wor ds, a s a n example, t h e 37 most f r e q u e n t words o f t h i s l e n g t h a c c o u n t f o r approximately one-half of all tokens of four-letter wo r d s . This guarantees, on t h e average, a high, positive c o r r e l a t i o n between d i f f e r e n t s t a t i s t i c a l measures. However, low summed s i n g l e - l e t t e r positional-frequency s t r i n g s w i l l u s u a l l y b e l o w i n summed p o s i t i o n a l b i g r a m an d t r i g r a m f r e q u e n c y , b u t s t r i n g s h i g h i n summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y a r e n o t n e c e s s a r i l y h i g h i n t h e o t h e r two m e a s u r e s . Furthermore, s i n c e t h e extremely h i g h frequency words i n E n g l i s h a r e m o s t l y t h r e e , f o u r , and ( t o a l e s s e r d e g r e e ) five l e t t e r s i n l e n g t h , t h e i n f l u e n c e of t h e h i g h e s t frequency words n e c e s s a r i l y d e c r e a s e s w i t h i n c r e a s i n g word l e n g t h . T h u s , we would e x p e c t a l o w e r c o r r e l a t i o n b e t w e e n b i g r a m an d t r i g r a m counts i n seven-letter s t r i n g s than i n f o u r - l e t t e r s t r i n g s . The c e n t r a l l i m i t a t i o n i n f r e q u e n c y - b a s e d s c h e m e s , e v e n when p o s i t i o n and word l e n g t h s a r e o b s e r v e d , i s t h a t t h e y c a n g e n e r a t e p s e u d o w o r d s w h i c h v i o l a t e E n g l i s h p h o n o l o g i c a l an d spelling conventions. F o r e x a m p l e , t h r s m , s t h s e , an d w h r s t a r e


29

unpronounceable b u t have relatively high summed b i g r a m p o s i t i o n a l c o u n t s . These can be c o n t r a s t e d w i t h b i p o n , s l e v y , and d u f i p , which h a v e r e l a t i v e l y low summed b i g r a m p o s i t i o n a l counts, but a r e legal from a rule-governed standpoint. V i o l a t i o n s c a n b e a v o i d e d , f o r t h e most p a r t , by u s i n g position-sensitive f o u r t h - o r d e r a p p r o x i m a t i o n s which a r e a l s o h i g h i n summed t r i g r a m p o s i t i o n a l c o u n t s . PHONOLOGICALLY-BASED DESCRIPTIONS An a l t e r n a t i v e t o s t a t i s t i c a l r e d u n d a n c y h a s been t o u s e the relationship between spelling and sound (i.e. , pronounceability) as a d e f i n i n g m e t r i c . Gibson e t a l . (1962) f o u n d t h a t l e t t e r s o f p r o n o u n c e a b l e pseudowords were more easily recalled in a f u l l r e p o r t t h a n were l e t t e r s o f u n p r o n o u n c e a b l e nonwords ( e . g . , dink v s . G ) .The a u t h o r s h y p o t h e s i z e d t h a t t h e o p e r a t i v e u n i t i n word p e r c e p t i o n was n o t t h e l e t t e r ( o r t h e whole w o r d ) , b u t a s e q u e n c e o f l e t t e r s which had an i n v a r i a n t s p e l l i n g - t o - s o u n d relationship. However, (1970) obtained the same r e s u l t s w i t h Gibson e t a l . congenitally deaf s u b j e c t s , thereby demonstrating t h a t t h e spelling-to-sound r e l a t i o n s h i p could not alone account f o r t h e response d i f f e r e n c e s . I t is l i k e l y t h a t o r t h o g r a p h i c s t r u c t u r e d i f f e r e n c e s (whether frequency-based o r rule-governed) were critical. L e t t e r - s o u n d c o r r e s p o n d e n c e s h a v e a l s o been u t i l i z e d i n word r e c o g n i t i o n models by R u b e n s t e i n , L e w i s , and R u b e n s t e i n ( 1 9 7 1 ) and by S m i t h and Spoehr ( 1 9 7 4 ) . However, b o t h t h e p a r a d i g m employed and the assumed u s e of l e t t e r - s o u n d r e l a t i o n s h i p s i n t h e l a t t e r two s t u d i e s d i f f e r e d from t h a t i n ( 1 9 7 1 ) and S m i t h Gibson e t a l . ( 1 9 6 2 ) . Both R u b e n s t e i n e t a l . and Spoehr ( 1 9 7 4 ) assumed t h a t l e t t e r r e c o g n i t i o n o c c u r s o n t h e b a s i s of l e t t e r f e a t u r e s ; t h en sounds a r e a t t a c h e d t o l e t t e r s o r l e t t e r s e q u e n L e s and l e x i c a l a c c e s s made o n t h e b a s i s o f a phonological u n i t . G i b s o n e t a l . ( 1 9 6 2 ) assumed t h a t word r e c o g n i t i o n o c c u r r e d on t h e b a s i s o f h i g h e r - o r d e r v i s u a l u n i t s which t h e r e a d e r formed t h r o u g h e x p e r i e n c e w i t h l e t t e r - s o u n d translation. The r e l i a b i l i t y o f any o f t h e s e h y p o t h e s e s , when viewed i n r e l a t i o n t o the c o m p l e x i t i e s of l e t t e r - s o u n d c o r r e s p o n d e n c e s i s q u e s t i o n a b l e ( c f . Venezky, 1 9 7 0 ) . Furthermore, some e m p i r i c a l evidence indicates that p h o n o l o g i c a l e n c o d i n g is n o t n e c e s s a r y f o r l e x i c a l a c c e s s ( K l e i m a n , 1 9 7 5 ; Levy, 1 9 7 8 ; M a s s a r o , 1 9 7 8 ; 1979b; Tzeng, Hung, & Wang, 1 9 7 7 ) . However, e v e n i f p h o n o l o g i c a l t r a n s l a t i o n w e r e shown t o p l a y a r o l e i n word r e c o g n i t i o n , pronounceability

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a l o n e would s t i l l be i n a d e q u a t e f o r d e s c r i b i n g o r t h o g r a p h i c structure. E n g l i s h s p e l l i n g i s c o n s t r a i n e d by p h o n o l o g i c a l c o n v e n t i o n s f i r s t , b u t a l s o by s c r i b a l c o n v e n t i o n s , which outlaw c e r t a i n p o s s i b l e b u t pronounceable s p e l l i n g s i n s e l e c t e d contexts.

RULE-GOVERNED

REGULARITY

Rule-governed regularity describes the predictable s t r u c t u r e of t h e o r t h o g r a p h y i n t e r m s of p h o n o l o g i c a l and scribal constraints. However, a c r i t i c a l f e a t u r e of t h i s p r e d i c t a b l e s t r u c t u r e of l e t t e r d e s c r i p t i o n is t h a t t h e o c c u r r e n c e s i s u t i l i z e d w i t h o u t a n y m e d i a t i o n of t h e s p o k e n language. I n c o n t r a s t t o t h e s p e l l i n g - t o - s o u n d d e s c r i p t i o n of Gibson e t a l . ( 1 9 6 2 ) , R u b e n s t e i n e t a l . ( 1 9 7 1 ) , and S m i t h and of orthographic structure in Spoehr (1974) , u t i l i z a t i o n p e r c e p t u a l r e c o g n i t i o n i s assumed t o o c c u r b e f o r e t h e p r i n t e d Although much o f t h e s t r u c t u r e p a t t e r n i s t r a n s l a t e d t o sound. of a w r i t t e n a l p h a b e t i c l a n g u a g e n e c e s s a r i l y f o l l o w s i t s phonology, a c c e s s t o t h e phonology i s n o t n e c e s s a r y f o r u t i l i z a t i o n of t h e o r t h o g r a p h i c s t r u c t u r e . Direct evidence f o r t h i s a s s u m p t i o n comes from t h e u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e by d e a f r e a d e r s ( G i b s o n e t a l . , 1 9 7 0 ) . I n a d d i t i o n , Singer ( i n p r e s s ) found t h a t a p h o n o l o g i c a l r e n d e r i n g o f words p r e s e n t e d i n a n a r t i f i c i a l a l p h a b e t was n o t n e c e s s a r y f o r l e a r n i n g and u t i l i z i n g o r t h o g r a p h i c s t r u c t u r e . I n the sections which f o l l o w , b o t h t h e p h o n o l o g i c a l and t h e s c r i b a l c o n s t r a i n t s of Engl i sh s p e l l i n g s a r e o u t l i n e d . Phonological Constraints The p r i m a r y c o n s t r a i n t s on E n g l i s h o r t h o g r a p h y d e r i v e from t h e a l l o w a b l e s e q u e n c e s o f s o u n d s i n E n g l i s h words. Thus, / s k / i s an a l l o w a b l e i n i t i a l c o n s o n a n t c l u s t e r and t h e r e f o r e E, on t h e o t h e r h a n d , spellings for it e x i s t (e.g., / t l / and / d l / d o n o t o c c u r and n e v e r d i d o c c u r i n i t i a l l y i n E n g l i s h w o r d s , and t h e r e f o r e no s p e l l i n g f o r t h e s e s e q u e n c e s o c c u r i n E n g l i s h words ( b u t t h e y d o i n T l i n g i t and s e v e r a l o t h e r l a n g u a g e s i n which i n i t i a l / t l / and / d l / are legal). C o m p l i c a t i n g t h i s r e l a t i o n s h i p between sound and s p e l l i n g , however, a r e s e v e r a l f a c t o r s , i n c l u d i n g s c r i b a l p e d a n t r y , which l e a v e u s w i t h s p e l l i n g s f o r (1) sound s e q u e n c e s which o n c e o c c u r r e d , b u t have s i n c e been d r o p p e d from t h e l a n g u a g e ( e . g . , WL-, &-, F-), o r f o r ( 2 ) sound s e q u e n c e s t h a t were presumed

e, e);


31

t o h a v e o c c u r r e d i n t h e l a n g u a g e from which a word was borrowed this (e.g., p s y c h o l o g y , p t a r m i g a n , debt). For p s y c h o l o g y , a s s u m p t i o n i s s u p p o r t a b l e ; f o r p t a r m i g a n i t is c l e a r l y b a s e d on m i s t a k e n e t y m o l o g y ; and f o r debt ( a n d v a r i o u s o t h e r s ) , i t i s o n l y p a r t i a l l y t r u e , i n t h a t /b/ and / t / o c c u r r e d i n t h e L a t i n a n c e s t o r of debt ( d e b i t u m ) , b u t n o t a s a f i n a l c l u s t e r . A f u r t h e r c o m p l i c a t i o n is t h e d e v i a t i o n i n s e r i a l o r d e r of s e v e r a l s p e l l i n g s from t h e order of s o u n d s which t h e y represent. C h i e f among t h e s e i s %, a s p e l l i n g which a t l e a s t some E n g l i s h s p e a k e r s h a v e r e t a i n e d a s /hw/, and -& a s i n b o t t l e , e t c . , which s p e l l s ( i n d e l i b e r a t e s p e e c h ) /al/ (&and -1e - a r e s c r i b a l r e v e r s a l s o f e a r l i e r k- and B u t e v e n w i t h t h e s e d e v i a t i o n s from e x p e c t e d p r a c t i c e , most E n g l i s h s o u n d s a r e r e p r e s e n t e d i n a m o d e r a t e l y r a t i o n a l f a s h i o n i n t h e o r t h o g r a p h y (Venezky, 1 9 7 0 ) . However, s i n c e E n g l i s h p o s s e s s e s more t h a n one p o t e n t i a l s p e l l i n g f o r a l m o s t e v e r y s o u n d , a s e c o n d s e t of c o n s t r a i n t s , h e r e c a l l e d s c r i b a l c o n s t r a i n t s , e n t e r i n t o rule-governed orthographic s t r u c t u r e .

-e).

Scribal Constraints To e x p l a i n t h e r u d i m e n t s of t h e s e c o n s t r a i n t s , some new terminology is h e l p f u l . Vowel s p e l l i n g s a r e c l a s s e d a s p r i m a r y ( 2 , g, i f 0 , g, y ) o r s e c o n d a r y (&, 3 , ", ", e t c . ) . Consonant s p e l l i n g s a r e e i t h e r f u n c t i o n a l l y s i m p l e (b, c, c h , d , e t c . ) o r f u n c t i o n a l l y compound (11, 3, and 3). Graphemic c o n s t r a i n t s r e g u l a t e p r i m a r i l y t h e d i s t r i b u t i o n (1) g e m i n a t e d (double) letters, (2) and (3) of y-1. F i r s t , u n l i k e S p a n i s h , E n g l i s h r e s i s t s d o u b l e d l e t t e r s i n word-initial p o s i t i o n , e s p e c i a l l y c o n s o n a n t s . Only a h a n d f u l o f e x c e p t i o n s t o t h i s e x i s t s , p r i m a r i l y i n v o l v i n g t h e form 00 (e.g., oodles, ooze). I n other p o s i t i o n s only 15 l e t t e r s can d o u b l e : t h o s e t h a t d o n ' t ( o r r a r e l y d o ) a r e 2 , h, A, i, &, g , 2 , y, 5 , y. B u t t h e r e a r e f u r t h e r r e s t r i c t i o n s . With few e x c e p t i o n s , doubled c o n s o n a n t s do n o t occur a f t e r secondary v o w e l s , and i n f i n a l p o s i t i o n o n l y ff, 11, and a r e common. F i n a l l y , t h e digraph u n i t s a r e n o t allowed t o double. For o n e , c h , a p s e u d o g e m i n a t e (3) was a d o p t e d i n e a r l y modern E n g l i s h , a t a b o u t t h e same t i m e t h a t 3 was a d o p t e d t o r e p r e s e n t d o u b l e d 9 when i t r e p r e s e n t e d / j / . S i m i l a r l y , & was i n v e n t e d f o r d o u b l e k which now o c c u r s o n l y i n i n f l e c t e d f o r m s o f trek (e.g. , t r e k k i n g ) . A s e c o n d s e t of graphemic c o n s t r a i n t s r e g u l a t e t h e d i s t r i b u t i o n of 2-y-w and 4-y. From t h e Middle E n g l i s h p e r i o d

=, *, u-v-w,

w,

32

CHAPTER 3

v

up t o a b o u t t h e m i d d l e of t h e 1 7 t h c e n t u r y , y and were used i n d i s c r i m i n a t e l y t o r e p r e s e n t / u / and / v / , a l t h o u g h v t e n d e d t o (According t o P y l e s ( 1 9 6 4 ) , be used i n i t i a l l y and 3 e l s e w h e r e . v was a l s o p r e f e r r e d i n t h e v i c i n i t y o f m and n). D i g r a p h s like O ,J when w r i t t e n b e f o r e a vowel m i g h t be m i s t a k e n f o r 3 ; therefore ; was d o u b l e d , and e v e n t u a l l y w r i t t e n y. I n time, 2 i n f i n a l p o s i t i o n a s t h e second p a r t o f a s e c o n d a r y vowel s p e l l i n g was r e p l a c e d by y, g i v i n g t h e p r e s e n t - d a y a l t e r n a t i o n s au/aw, - eu/ew, and ou/ow. I n g e n e r a l , t h e variant occurs b e f o r e v o w e l s and i n f i n a l p o s i t i o n ; t h e 3 v a r i a n t o c c u r s e l s e w h e r e . Where 2 would o c c u r a s a p r i m a r y vowel s p e l l i n g i n f i n a l p o s i t i o n , a f i n a l e i s added ( e . g . , blue). For r e a s o n s n o t a l t o g e t h e r c l e a r , b u t r e l a t e d t o t h e a m b i g u i t y of 3-v s p e l l i n g s , y was a l s o e x o r c i s e d from f i n a l position. B u t s i n c e no s i m p l e r e p l a c e m e n t was a v a i l a b l e a s was f o r 2 , a n e was added a f t e r t h e l e t t e r , t h u s g i v i n g p r e s e n t - d a y s p e l l i n g s l i k e d o v e , l o v e , and have, where t h e f i n a l e d o e s n o t mark a f r e e ( l o n g ) vowel p r o n u n c i a t i o n . S i m i l a r l y , I-y now a l t e r n a t e e x a c t l y a s y and )1! d o , a s second e l e m e n t s of a d i g r a p h v o w e l , t h u s , maid/may, oil/boy, and either/-. T h r e e a d d i t i o n a l f e a t u r e s of E n g l i s h s p e l l i n g which have l i m i t e d u t i l i t y i n s o u n d - t o - s p e l l i n g r u l e s , b u t which a r e i m p o r t a n t f o r t h e r e c o g n i t i o n of r e a l w o r d s , a r e d i s c u s s e d b r i e f l y i n t h e following s e c t i o n .

w

Morphemic F e a t u r e s Morpheme I d e n t i t y . The r e t e n t i o n o f morphemic i d e n t i t y a s i n p a i r s l i k e cone/conic is a n a t u r a l consequence of c o n d i t i o n e d sound c h a n g e unaccompanied by a c o r r e s p o n d i n g s p e l l i n g c h a n g e and n o t t h e r e s u l t o f o v e r t s c r i b a l i n t e n t i o n . For t h e most p a r t , however, r e t e n t i o n o f morphemic i d e n t i t y is l i m i t e d t o vowels and t h o s e c o n s o n a n t l e t t e r s which a r e s i l e n t i n one form b u t pronounced i n a r e l a t e d o n e . In the f i r s t category a r e alternations of the form s a n e / s a n i t y and telegraph/telegraphy; in the latter are p a i r s akin t o sign/signal, bomb/bombard, and hymn/hymnal. Where no s i n g l e s p e l l i n g can s t a n d f o r a p a i r of sounds, c o n s i s t e n t s p e l l i n g of a l l o m o r p h s which d i f f e r by t h o s e s o u n d s is n o t p o s s i b l e . Thus, c o l l i d e / c o l l i s i o n m u s t u t i l i z e d i f f e r e n t s p e l l i n g s f o r /d/ and

/:/. I n bound morphemes, s i m i l a r p r o c e s s e s c a n be s e e n e x e m p l i f i e d by t h e noun p l u r a l ( a n d t h i r d - p e r s o n s i n g u l a r ) and t h e p a s t t e n s e m a r k e r , -3.

as

-2


33

P a r t l y by a c c i d e n t an d p a r t l y S e p a r a t i o n of homophones. by o v e r t attention, English spelling has tended to d i f f e r e n t i a t e homophones w h e r e v e r o r t h o g r a p h i c l i c e n s e w o u l d belong allow. P a i r s l i k e s e a / s e e , b l u e / b l e w , an d r i g h t / w r i t e t o t h e accident category, b u t foul/fowl, plain/plane, and s u n / son r e s u l t from o v e r t s c r i b a l p r a c t i c e (Vachek, 1959, 1973; on t h e o r t h o g r a p h i c d i s t i n c t i v e n e s s o f homophones, see O l s o n & Kausler, 1971). The t w o - l e t t e r word b a n . S i n c e a t l e a s t t h e time o f Noah W e b s t e r an d p r o b a b l y b e f o r e , English l e x i c o g r a p h e r s have a v o i d e d e x t e n d i n g t h e r e p e r t o i r e o f t w o - l e t t e r w o r d s b ey o n d a small g r o u p o f f u n c t i o n w o r d s ( e . g . , &, of, if). Two m ech an i s m s w e r e a d o p t e d f o r l e n g t h e n i n g t w o - l e t t e r w o r d s w h i c h d i d n ' t q u a l i f y f o r inclusion in t h i s group: doubling t h e f i n a l and or adding a f i n a l c o n s o n a n t , a s i n ebb, add, odd, -e , ( e . g . , doe, hoe, &, a n d * ) . The f o r m e r m ech an i sm h a s c r e a t e d u n i q u e f i n a l c o n s o n a n t c l u s t e r s i n t h a t b, fi, 9, a n d 1 d o n o t d o u b l e i n f i n a l p o s i t i o n i n any o t h e r E n g l i s h words. These graphemic c o n s t r a i n t s have evolved independently o f sound, f o r u n l i k e t h e o r t h o g r a p h i e s of o t h e r major languages, modern E n g l i s h s p e l l i n g p r e s e r v e s c l e a r e v i d e n c e o f n e a r l y 1,300 y e a r s of sound change, s c r i b a l tampering, partial r e f o r m s , and f o r e i g n i n t r u s i o n s . There is a n u n d e r l y i n g p a t t e r n t o t h i s o r t h o g r a p h y , a s d e s c r i b e d i n V en ezk y ( 1 9 7 0 ) , b u t t h e r e is a l s o a s u b s t a n t i a l m a r g i n a l mess w h i c h c a n o n l y i n p a r t b e o r g a n i z e d i n t o s u b p a t t e r n s o r j u s t i f i e d by a p p e a l t o s u c h p r i n c i p l e s a s t h e o r t h o g r a p h i c s e p a r a t i o n o f homophones (e.g., bell/belle). Nevertheless, permeating the entire s p e l l i n g s y s t e m f r o m o r g a n i z e d c o r e t o t h e most d i s j o i n t o u t e r f r i n g e s i s a n i n t e r a c t i o n b e t w e e n p h o n o l o g i c a l an d v i s u a l f o r c e s which r a n g e s from p r o d u c t i v e c o u n t e r p o i n t a s i n s u c h s p e l l i n g s a s c o n e / c o n i c t o t h e d i s s o n a n c e o f s u c h mots n o i r s a s women. S i n c e n o E n g l i s h l a n g u a g e academy e v e r imposed a g r a n d d e s i g n on E n g l i s h s p e l l i n g , what g e n e r a l p r i n c i p l e s t h e r e a r e r e s u l t e d from t h e c o n f l u e n c e o f v a r i o u s s c r i b a l t r a d i t i o n s w i t h t h e p e r i o d i c r a v a g e s o f s o u n d c h a n g e u nacco m p an i ed b y s p e l l i n g Y e t a p r i n c i p l e of s o r t s d o e s emerge from t h e c u r r e n t change. system, v i z . , "Accede t o a l l v i s u a l i n t e r e s t s up t o , b u t n o t beyond, t h e p o i n t where p a s s a g e from s p e l l i n g t o sound is impaired."

on,

a,

34

CHAPTER 3

P s y c h o l o g i c a l Assumptions Rule-governed descriptions of orthographic s t r u c t u r e d i f f e r from o t h e r d e f i n i t i o n s o f o r t h o g r a p h i c s t r u c t u r e i n two aspects: First, i n t h e u t i l i z a t i o n of word t y p e s r a t h e r t h a n word t o k e n s , and s e c o n d , i n c l a s s i f y i n g a s r e g u l a r c e r t a i n s p e l l i n g s which d o n o t o c c u r ( y e t ) i n E n g l i s h words and c l a s s i f y i n g a s i r r e g u l a r some t h a t d o . The f i r s t d i f f e r e n c e is n o t e s s e n t i a l t o t h e d e f i n i t i o n of o r t h o g r a p h i c s t r u c t u r e , b u t i t is probably more a reflection of the differing e p i s t e m o l o g i e s of l i n g u i s t s and p s y c h o l o g i s t s . The s e c o n d d i f f e r e n c e , however, i s c e n t r a l t o t h e c o n c e p t o f o r t h o g r a p h i c s t r u c t u r e and r e q u i r e s f u r t h e r e x p l i c a t i o n . The p r i m a r y a s s u m p t i o n b e h i n d t h e o r t h o g r a p h i c r u l e s p r e s e n t e d h e r e i s t h a t r e a d e r s a b s t r a c t from t h e i r e x p e r i e n c e s w i t h p r i n t e d words t h o s e s p e l l i n g s t h a t a r e p r o d u c t i v e i n present-day E n g l i s h and u s e t h e s e t o f a c i l i t a t e r e c o g n i t i o n . For e x a m p l e , s i l e n t i n i t i a l letters, regardless of t h e f r e q u e n c y o f o c c u r r e n c e o f t h e words i n which t h e y o c c u r , a r e c l a s s i f i e d a s i r r e g u l a r s i n c e i t is u n l i k e l y t h a t new words b r o u g h t i n t o t h e E n g l i s h l a n g u a g e would e v e r be s p e l l e d w i t h them. ( S p e l l i n g a n a l o g i e s might p r e s e n t an e x c e p t i o n t o t h i s a s s u m p t i o n and c a n n o t b e i g n o r e d . However, i t i s u n l i k e l y t h a t s i l e n t i n i t i a l s p e l l i n g s would e v e r be w i d e l y e x t e n d e d . ) and On t h e o t h e r h a n d , t h e i n i t i a l s e q u e n c e s E-and t h e f i n a l s e q u e n c e s -eng, -&, and -ofe d o n o t o c c u r i n t h e f i r s t 2 0 , 0 0 0 words i n t h e T h o r n d i k e and Lorge ( 1 9 4 4 ) l i s t , y e t t h e y a r e c l a s s i f i e d as o r t h o g r a p h i c a l l y r e g u l a r s i n c e t h e y d o n o t v i o l a t e any phonological or scribal pattern. Thus pseudowords l i k e 9, woach, t r e n g , d e r l , and s t r o f e a r e p r o n o u n c e a b l e and s t r u c t u r a l l y r e g u l a r , even though t h e y c o n t a i n t r i g r a m s t h a t d o n o t o c c u r i n E n g l i s h words. The p e r c e p t u a l r e c o g n i t i o n of such s t r i n g s r e l a t i v e t o s i m i l a r pseudowords w i t h h i g h e r summed t r i g r a m c o u n t s i s a n i s s u e t h a t r e m a i n s t o be i n v e s t i g a t e d .

e-

Dichotomy I s s u e Another issue which merits empirical investigation c o n c e r n s t h e assumed d i c h o t o m o u s d e t e r m i n a n t s of o r t h o g r a p h i c r e g u l a r i t y . Given the two different constraints on orthographic s t r u c t u r e discussed above, w e should q u e s t i o n whether o r n o t t h e s c r i b a l and p h o n o l o g i c a l e l e m e n t s a r e Are, f o r e x a m p l e , i r r e g u l a r s t r i n g s separated psychologically. like and c k l i b p r o c e s s e d d i f f e r e n t l y from a n i l l e g a l


35

s t r i n g l i k e t p r i f ? A l l a r e i l l e g a l and n o n - o c c u r r i n g , y e t t h e y d i f f e r i n type of illegality. Tprif contains an i n i t i a l c o n s o n a n t c l u s t e r t h a t is p h o n o l o g i c a l l y i l l e g a l and t h e r e f o r e scribally non-occurring. and cklib are both phonologically acceptable, but c o n t a i n s c r i b a l l y outlawed features, viz., final in and i n i t i a l & i n c k l i b . For example, d o e s t h e p r o b a b i l i t y of c o r r e c t l y i d e n t i f y i n g a t a r g e t l e t t e r depend upon w h e t h e r i t is i n a p h o n o l o g i c a l l y - i l l e g a l or a scribally-illegal t e s t string?

AN I N I T I A L ALGORITHM FOR RULE-GOVERNED

REGULARITY

The a p p r o a c h t h a t we p r o p o s e , b u t h a v e n o t y e t f u l l y the disparate patterns j u s t d e v e l o p e d , for r e p r e s e n t i n g d e s c r i b e d i s t o c o n s t r u c t a s e t o f g e n e r a t i v e r u l e s which b e g i n by s e l e c t i n g a c o n s o n a n t - v o w e l - c o n s o n a n t structure for a p h o n o l o g i c a l word. Replacement r u l e s a r e a p p l i e d t o expand l e f t t o r i g h t o f e a c h vowel and e a c h c o n s o n a n t u n i t u n t i l a p h o n o l o g i c a l l y l e g a l s t r i n g r e s u l t s . A s e c o n d s e t of r u l e s then a p p l i e s sound-to-spelling rules t o generate a l e g a l pseudoword (or w o r d ) . By r e l a x i n g r u l e s a t v a r i o u s l e v e l s o f generation, we can then generate l e t t e r s t r i n g s with c o n t r o l l e d i r r e g u l a r i t i e s . For e x a m p l e , by removing t h e p l a c e r e s t r i c t i o n on f i n a l c l u s t e r s o f t h e form NASAL + STOP, w e g e n e r a t e u n p r o n o u n c e a b l e f i n a l c l u s t e r s l i k e -9 and -g. On t h e o t h e r h a n d , a l l o w i n g f i n a l /v/ t o be r e p r e s e n t e d by 1 r a t h e r t h a n a l l o w s s c r i b a l l y i l l e g a l f o r m s l i k e mov and s l a i v . So f a r , a p r e l i m i n a r y s e t of r u l e s f o r g e n e r a t i n g l e g a l m o n o sy lla b le s h a s been d e v e l o p e d , d r a w i n g o n a v a r i e t y o f s o u r c e s ( e . g . , Whorf, 1970). A 1 9 5 6 ; K u r a t h , 1 9 6 4 ; Chomsky & H a l l e , 1 9 6 8 ; Venezky, s a m p l e d e r i v a t i o n o f a l e g a l pseudoword from t h e s e r u l e s i s shown i n T a b l e 3 . 1 . I n summary, w e h a v e p r e s e n t e d two g e n e r a l a p p r o a c h e s t o d e s c r i b i n g o r t h o g r a p h i c s t r u c t u r e : s t a t i s t i c a l r e d u n d a n c y and For t h e f o r m e r , c l a s s m e t r i c s a r e rule-governed regularity. d e r i v e d from f u n c t i o n s o n t h e f r e q u e n c i e s w i t h which v a r i o u s s i z e u n i t s o c c u r ( e . g . , summed b i g r a m c o u n t s ) . For t h e l a t t e r c l a s s we h a v e s u g g e s t e d t h a t a c o m p a r a b l e m e t r i c m i g h t b e d e v e l o p e d t h r o u g h a s e t o f g e n e r a t i v e r u l e s which c o u l d b e v i o l a t e d a t v a r i o u s l e v e l s t o p r o d u c e nonwords w i t h c o n t r o l l e d d e v i a t i o n s from r u l e - g o v e r n e d r e g u l a r i t y .

36

CHAPTER 3

Table 3.1 A.

Apply Base Generation Rules

Step

Rule -

Result

Initialize

1

w ----->

2

3 4

5 6 7 8

9 10

11 12 13 B.

Derivation of a legal pseudoword (a).

#W# # c+v+c# #CC+V+C# # SCL+V+C# #g+NASAL+V+C# #s+"+V+C # #S+"+Vf+C# #s+E+vfr+C# tg+n+i+c# #s+E+i+CS# #s+g+i+STOPg# #s+g+i-+STOPvg#

cvc

C/# -------> cc CC/# -------> SCL SCL ------ > s+NASAL 11. NASAL -----> V/else -----> Vf vfr Vf/else ----> 4 Vfr -----> C/-# ----- > cs CS/Vf-# ---- > STOPg STOPg ----- > STOPVg STOPvg -----> b

#S+"+i+b#

Apply Base-to-Spelling Rules

Step.

14 15 16 17

Rule s/else

n ----> -i/-Cs#

Result

---->

----> ------------b -

<s>

#<El>*#

<e...e#>

# < sn>i&# #<sne>b<e># # < snebe>#

---- >

(a)Terminal phonological symbols are underlined; terminal spelling symbols occur in wedges, e.g., . A rule of the form x/# ------- > Y is read "Rewrite X as Y when X occurs after juncture ( I ) .'I

4

Experimental Studies

The r e s e a r c h r e p o r t e d i n t h i s book e v o l v e d from a commonality o f i n t e r e s t s among t h e a u t h o r s . These i n t e r e s t s p r i m a r i l y c e n t e r e d around f u r t h e r i n g t h e u n d e r s t a n d i n g o f t h e perceptual processes involved in word r e c o g n i t i o n and especially delineating the r o l e t h a t orthographic s t r u c t u r e plays in these processes. An e x t e n s i o n of a n i n t e r e s t i n g s t u d y by Mason ( 1 9 7 5 ) a p p e a r e d t o be a p r o d u c t i v e way t o a t t a c k t h e p r o b l e m s o f o r t h o g r a p h i c s t r u c t u r e and p e r c e p t u a l r e c o g n i t i o n of words. Mason evaluated the c o n t r i b u t i o n o f summed single-letter p o s i t i o n a l frequency i n a t a r g e t search task. Good and p o o r r e a d e r s i n d i c a t e d w h e t h e r o r n o t a s i x - l e t t e r s t r i n g c o n t a i n e d a p r e d e t e r m i n e d t a r g e t l e t t e r . Good r e a d e r s a v e r a g e d 6 3 msec f a s t e r f o r s t r i n g s h i g h t h a n f o r s t r i n g s low We w e r e c o n c e r n e d w i t h two p r i m a r y i n p o s i t i o n a l frequency. i s s u e s w i t h r e s p e c t t o Mason's r e s u l t s . F i r s t , w e q u e s t i o n e d w h e t h e r a f r e q u e n c y m e a s u r e of o r t h o g r a p h i c s t r u c t u r e was s u f f i c i e n t t o d e s c r i b e t h e f a c i l i t a t i n g e f f e c t s of s t r u c t u r e on perceptual recognition. As discussed in Chapter 3 , a rule-governed d e s c r i p t i o n o f o r t h o g r a p h i c s t r u c t u r e may b e a more a p p r o p r i a t e r e p r e s e n t a t i o n o f t h e r e a d e r ' s knowledge. S e c o n d , Mason's r e s u l t s a p p e a r e d t o be h i g h l y v a r i a b l e and we q u e s t i o n e d whether t h e t a r g e t s e a r c h t a s k u s i n g r e a c t i o n time a s a d e p e n d e n t measure reveals l a r g e e f f e c t s of orthographic structure. T h e r e were a number of r e a s o n s t o suspect the robustness of the effect in Mason's s t u d y . S u b j e c t s had o n l y 5 p r a c t i c e t r i a l s and j u s t 7 2 experimental t r i a l s . Each s u b j e c t was t e s t e d on 2 4 w o r d s , 24 s t r i n g s h i g h i n p o s i t i o n a l f r e q u e n c y , and 2 4 s t r i n g s low i n p o s i t i o n a l f r e q u e n c y . Given 1 2 good r e a d e r s , t h e r e were 288 o b s e r v a t i o n s minus e r r o r s c o n t r i b u t i n g t o e a c h e x p e r i m e n t a l

38

CHAPTER 4

c o n d i t i o n . Mason found t h a t 1 0 0 p r a c t i c e t r i a l s i n a f o l l o w u p e x p e r i m e n t r e d u ced t h e a d v a n t a g e of p e r f o r m a n c e on s t r i n g s h i g h i n summed p o s i t i o n a l f r e q u e n c y t o a n a v e r a g e of a b o u t 2 2 msec. S i n c e p r a c t i c e t r i a l s r e d u c e d t h e a d v a n t a g e by a b o u t t w o - t h i r d s we f e l t t h a t a r e p l i c a t i o n o f Mason's s t u d y w i t h improved methodology was n e c e s s a r y t o d e t e r m i n e t h e r e l i a b i l i t y of h e r results.

MASSARO ET AL. 1979 STUDIES M a s s a r o , Venezky, and T a y l o r ( 1 9 79) r e p l i c a t e d Mason's experiment using t h e t a r g e t search t a s k with sixth-grade subjects. To o b t a i n g r e a t e r r e l i a b i l i t y , b o t h t h e number of o b s e r v a t i o n s and t h e number of t e s t s t i m u l i were i n c r e a s e d . F u r t h e r m o r e , t h e l e t t e r s t r i n g s were n o t o n l y h i g h and low i n p o s i t i o n a l f r e q u e n c y b u t a l s o were c o n t r a s t e d a l o n g a n o t h e r d i m e n si o n which we c a l l e d o r t h o g r a p h i c r e g u l a r i t y . We had n o t y e t d e v e l o p e d a s y s t e m a t i c r u l e - b a s e d d e s c r i p t i o n of E n g l i s h o r t h o g r a p h y , b u t we wer e a b l e t o c h o o s e s t r i n g s t h a t a p p e a r e d t o be r e g u l a r o r i r r e g u l a r . T h e r e f o r e , a l t h o u g h we had no s y s t e m a t i c d e s c r i p t i o n of r e g u l a r i t y , we f e l t that the d e c i s i o n s we made t o c h o o s e s t r i n g s t h a t were r e g u l a r and i r r e g u l a r would p r o v i d e a t e s t of wh ethe r t h e f a c i l i t a t i n g e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e c o u l d be c o m p l e t e l y a c c o u n t e d f o r by t h e p o s i t i o n a l f r e q u e n c y h y p o t h e s i s propose d by Mason. To c r e a t e t h e t e s t s t i m u l i , Massaro e t a l . (1979) s e l e c t e d f o u r anagrams from e a c h o f 40 s i x - l e t t e r words s u c h t h a t t h e anagrams were e i t h e r h i g h or low i n s i n g l e - l e t t e r positional f r e q u e n c y and e i t h e r r e g u l a r or i r r e g u l a r . The r e s u l t i n g 2 x 2 f a c t o r i a l design provides a direct assessment of t h e c o n t r i b u t i o n s o f f r e q u e n c y and r e g u l a r i t y on l e t t e r - s t r i n g perception. Each o f t h e s i x t h g r a d e r s be ga n by t a k i n g a w r i t t e n c o m p reh en s i o n t e s t . The t a r g e t s e a r c h t a s k was t h e n i n t r o d u c e d by showing t h e s u b j e c t s t h e v i s u a l d i s p l a y and t h e r e s p o n s e p a n e l . To a c q u a i n t t h e s u b j e c t s w i t h t h e r e s p o n s e p r o c e d u r e , t h e y were f i r s t 'given 50 t r i a l s o f r e s p o n d i n g " y e s " and "no" t o t h e words YES and NO p r e s e n t e d on t h e v i s u a l display. Each s u b j e c t pushed t h e " y e s " b u t t o n w i t h h i s o r h e r p r e f e r r e d hand. Nex t , t h e s u b j e c t s r e c e i v e d 50 p r a c t i c e t r i a l s w i t h random l e t t e r s t r i n g s . The s u b j e c t s were a s k e d t o i n d i c a t e w h e t h er o r n o t a t a r g e t l e t t e r was p r e s e n t i n t h e s i x - l e t t e r s t r i n g . Each t r i a l began w i t h t h e p r e s e n t a t i o n of t h e t a r g e t l e t t e r f o l l o w e d 800 msec l a t e r by t h e t e s t l e t t e r string. The t e s t l e t t e r s t r i n g remained on u n t i l t h e s u b j e c t

EXPERIMENTS ON LETTER AND WORD PERCEPTION

39

responded. S u b j e c t s were i n s t r u c t e d t o respond " y e s " i f t h e t a r g e t l e t t e r a p p e a r e d a t l e a s t o n c e i n t h e l e t t e r s t r i n g and "no" i f i t d i d n o t a p p e a r . The t a r g e t l e t t e r a p p e a r e d i n t h e l e t t e r s t r i n g on h a l f o f t h e t r i a l s ( t a r g e t t r i a l s ) and d i d n o t a p p e a r on t h e o t h e r h a l f ( c a t c h t r i a l s ) . They were t o l d t o The s u b j e c t s were t e s t e d on respond as a c c u r a t e l y a s p o s s i b l e . e a c h o f t h e u n i q u e 1 6 0 s t i m u l i , o n c e on t a r g e t t r i a l s and o n c e on c a t c h t r i a l s , g i v i n g r o u g h l y 8 0 o b s e r v a t i o n s p e r s u b j e c t a t each of t h e four experimental c o n d i t i o n s ( l e s s e r r o r t r i a l s ) . F i g u r e 4 . 1 g i v e s t h e r e s u l t s from t h i s i n i t i a l e x p e r i m e n t . Although t h e r e a c t i o n times were a b o u t 1 2 msec f a s t e r f o r

R-L

Figure 4.1

I-H

R e a c t i o n t i m e and p e r c e n t a g e c o r r e c t f o r s i x t h g r a d e r s a s a f u n c t i o n of o r t h o g r a p h i c r e g u l a r i t y and summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y f o r t a r g e t and c a t c h t r i a l s ( f r o m Massaro e t a l . , 1 9 7 9 ) (key: p = orthographically regular: I = orthographically irregular; ; = h i g h summed single-letter p o s i t i o n a l f r e q u e n c y ; & = low summed single-letter positional frequency).

CHAPTER 4

r e g u l a r t h a n f o r i r r e g u l a r s t r i n g s and a b o u t 1 2 msec f a s t e r f o r h i g h t h a n f o r low p o s i t i o n a l f r e q u e n c y , n e i t h e r r e s u l t was statistically significant. These r e s u l t s imply t h a t n e i t h e r p o s i t i o n a l frequency nor r e g u l a r i t y c o n t r i b u t e s i g n i f i c a n t l y t o p e r c e p t u a l r e c o g n i t i o n i n t h e t a r g e t s e a r c h t a s k . One r e a s o n c o u l d be t h a t our m a n i p u l a t i o n o f p o s i t i o n a l f r e q u e n c y and r e g u l a r i t y d i d n o t c a p t u r e t h e knowledge t h a t s u b j e c t s u t i l i z e i n p e r c e p t u a l r e c o g n i t i o n . A second p o s s i b i l i t y i s t h a t o u r manipulation of o r t h o g r a p h i c s t r u c t u r e d i d m i r r o r d i f f e r e n c e s i n t h e p s y c h o l o g i c a l r e a l i t y of t h e s e s t r u c t u r e s b u t t h a t t h e t a r g e t s e a r c h t a s k u s i n g r e a c t i o n times is i n s e n s i t i v e t o u t i l i z a t i o n of s t r u c t u r e . We s u s p e c t e d t h a t t h e small effects in the f i r s t e x p e r i m e n t were p r i m a r i l y due t o t h e t a r g e t s e a r c h t a s k r a t h e r t h a n t o t h e s t r i n g s u t i l i z e d i n t h e e x p e r i m e n t s . T h e r e f o r e , we c a r r i e d o u t two more e x p e r i m e n t s t o c o n t r a s t t h e t a r g e t s e a r c h t a s k u t i l i z i n g r e a c t i o n time ( R T ) a s a d e p e n d e n t measure w i t h a We t a r g e t s e a r c h t a s k u s i n g a c c u r a c y as a d e p e n d e n t measure. employed c o l l e g e s t u d e n t s r a t h e r t h a n s i x t h g r a d e r s a s s u b j e c t s s i n c e t h e y were more r e a d i l y a v a i l a b l e f o r t e s t i n g . One e x p e r i m e n t was a r e p l i c a t i o n o f our RT e x p e r i m e n t . The o t h e r , a n a c c u r a c y e x p e r i m e n t , involved a s l i g h t m o d i f i c a t i o n of a more common p a r a d i g m used to s t u d y t h e u t i l i z a t i o n of orthographic structure. In variants o f a Reicher-Wheeler p o s t c u e t a s k ( s e e C h a p t e r l ) , t h e s u b j e c t i s shown a word o r a nonword f o r a brief duration followed by a masking s t i m u l u s . Two a l t e r n a t i v e l e t t e r s a r e t h e n g i v e n and t h e s u b j e c t c h o o s e s which l e t t e r h e or s h e t h i n k s was p r e s e n t e d on that trial. I n o r d e r t o make t h i s a c c u r a c y t a s k c o m p a r a b l e t o t h e RT t a s k , we m o d i f i e d i t by p r e s e n t i n g j u s t one a l t e r n a t i v e l e t t e r a f t e r t h e masking s t i m u l u s . I n t h i s case t h e s i x - l e t t e r i t e m would b e p r e s e n t e d f o l l o w e d by a masking s t i m u l u s and t h e n t h e t a r g e t l e t t e r . The t a r g e t l e t t e r would b e p r e s e n t i n t h e t e s t item o n h a l f o f t h e t r i a l s and n o t p r e s e n t o n t h e o t h e r h a l f . The s u b j e c t s would s i m p l y i n d i c a t e w h e t h e r o r n o t t h e t a r g e t l e t t e r occurred i n t h e t e s t l e t t e r s t r i n g . Performance, i n t e r m s of r e a c t i o n time iri t h e f i r s t e x p e r i m e n t and o v e r a l l a c c u r a c y i n t h e second e x p e r i m e n t , r e f l e c t s how well t h e t e s t s t r i n g s were p e r c e i v e d . The r e s u l t s o f t h e s e two e x p e r i m e n t s a r e shown i n F i g u r e s 4.2 and 4 . 3 . I n t h e r e a c t i o n time t a s k , r e a c t i o n times averaged 16 msec faster for high than for low positional-frequency strings. R e s p o n s e s were 9 msec f a s t e r f o r r e g u l a r t h a n f o r i r r e g u l a r s t r i n g s . The a c c u r a c y t a s k showed t h a t r e s p o n s e a c c u r a c y was 5 % h i g h e r f o r r e g u l a r t h a n f o r


41

i r r e g u l a r s t r i n g s and 4 % h i g h e r f o r h i g h t h a n f o r low positional-frequency strings. A l l of these r e s u l t s were statistically significant. Therefore, although t h e magnitude o f t h e e f f e c t s on r e a c t i o n time f o r t h e a d u l t s was o f t h e same o r d e r of magnitude a s t h a t f o r t h e s i x t h g r a d e r s , lower v a r i a n c e among t h e a d u l t s made t h e e f f e c t s s t a t i s t i c a l l y significant. One l i m i t a t i o n a t t h i s s t a g e of t h e r e s e a r c h was t o know w h e t h e r o r n o t s i x t h g r a d e r s would g i v e s t a t i s t i c a l l y s i g n i f i c a n t accuracy r e s u l t s i n t h e accuracy task. However, s i n c e t h i s l a t t e r ' i n f o r m a t i o n was n o t a v a i l a b l e , w e were f a c e d w i t h t h e p r o b l e m of comparing t h e m a g n i t u d e of t h e r e a c t i o n t i m e r e s u l t w i t h t h e m a g n i t u d e of t h e a c c u r a c y r e s u l t and r e a l i z e d t h a t i t r e s e m b l e d t h a t o f comparing a p p l e s and o l i v e s . If it is accepted t h a t t h e r e a c t i o n t i m e r e s u l t is small,

750

-I

I

I

I

I

700

v)

Y

5F 2

650

600

%

550

Target

0 Catch

k

yK K

0 0

n Figure 4 . 2

100

90

nnnn R-H

R-L

I-H

I-L

R e a c t i o n time and p e r c e n t a g e c o r r e c t f o r c o l l e g e s t u d e n t s a s a f u n c t i o n of o r t h o g r a p h i c r e g u l a r i t y and summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y f o r t a r g e t and c a t c h t r i a l s ( f r o m Massaro e t a l . , 1979).

CHAPTER 4

42

t h e n o n e e x p l a n a t i o n f o r t h e small e f f e c t c o u l d t a k e t h e f o l l o w i n g form. I n t h e r e a c t i o n . t i m e t a s k t h e s u b j e c t was g i v e n t h e t a r g e t l e t t e r b e f o r e t h e t e s t s t r i n g was p r e s e n t e d . S i n c e t h e s u b j e c t s i m p l y was r e q u i r e d t o i n d i c a t e w he the r or n o t t h e t a r g e t was c o n t a i n e d i n t h e t e s t s t r i n g , h e or s h e may n o t h a v e had t o r e s o l v e c o m p l e t e l y a l l o f t h e l e t t e r s i n t h e s t r i n g b e f o r e a c o r r e c t d e c i s i o n was made. For e xa m ple , s u p p o se a s u b j e c t i s l o o k i n g f o r t h e t a r g e t l e t t e r i n the l e t t e r s t r i n g s c o s e , deom, and 9 r e s p e c t i v e l y . I n a l l cases t h e a p p r o p r i a t e r e s p o n s e is n o , b u t t h e s u b j e c t may be a b l e t o d e c i d e on t h i s f a s t e r w i t h some o f t h e s t r i n g s t h a n w i t h o t h e r s . Consider t h e following ar g um e nt. The re i s some e v i d e n c e t h a t o v e r a l l l e t t e r s h a p e c a n be r e s o l v e d and made a v a i l a b l e t o l a t e r s t a g e s of p r o c e s s i n g b e f o r e t h e l e t t e r is

'oo!7--90

c---oCatch

-

50

RH

Figure 4.3

R-L

I-H

I-L

Percentage c o r r e c t f o r c o l l e g e s t u d e n t s as a f u n c t i o n of o r t h o g r a p h i c r e g u l a r i t y and summed s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y f o r t a r g e t and c a t c h t r i a l s ( f r o m Massaro e t a l . , 1 9 7 9 ) .


Table 4 . 1

43

The s i x s e t s of l e t t e r s b a s e d o n t h e s i m i l a r i t y r e s u l t s o f Bouma ( 1 9 7 1 ) used by Massaro e t a l . (1979).

1. 2. 3.

4. 5.

6.

it

A l t h o u g h Bouma's a n a l y s i s i n d i c a t e d t h a t t h e f i r s t s e t c o u l d b e f u r t h e r d i v i d e d i n t o two s e t s c o n s i s t i n g of m , n , u , and r , v , w , t h e s e two s e t s were combined b e c a u s e o f t h e i r r e l a t i v e s i m i l a r i t y and t o p r o v i d e more r e l i a b l e d a t a by i n c r e a s i n g t h e number of o b s e r v a t i o n s w i t h i n a s e t .

c o m p l e t e l y r e c o g n i z e d (Bouma, 1 9 7 1 ; Massaro & S c h m u l l e r , 1 9 7 5 ) . t a r g e t s e a r c h t a s k c a n be used t o s t u d y t h e f e a t u r e s necessary for recognition. N e i s s e r (1963, 1967) f o r example, showed t h a t s u b j e c t s s e a r c h e d f a s t e r f o r a n u p p e r c a s e 2 i n a l i s t o f c u r v e d l e t t e r s t h a n i n a l i s t of l i n e a r l e t t e r s . T h i s r e s u l t i n d i c a t e s t h a t t h e s u b j e c t s were a b l e t o r e j e c t t h e c u r v e d l e t t e r s a s f o i l s more q u i c k l y t h a n t h e l i n e a r l e t t e r s . Applying t h i s a n a l y s i s t o t h e p r e s e n t e x a m p l e , s l i b j e c t s s h o u l d be a b l e t o r e s p o n d "no" q u i c k l y t o t h e e x t e n t t h a t none of t h e l e t t e r s i n t h e t e s t s t r i n g h a s t h e same o v e r a l l a s c e n d e r s h a p e a s t h e t a r g e t l e t t e r b. T h e r e f o r e , i t w i l l t a k e t h e s u b j e c t l o n g e r t o r e j e c t t h e s t r i n g deih t h a n t o r e j e c t t h e s t r i n g deom. The s t r i n g should be r e j e c t e d f a s t e s t of a l l . To t h e e x t e n t t h e s u b j e c t is a b l e t o u t i l i z e t h i s f e a t u r e d e t e c t i o n s t r a t e g y l t h e c o n t r i b u t i o n of orthographic s t r u c t u r e m i g h t be a t t e n u a t e d . T h e r e f o r e , i t was o f i n t e r e s t t o s e e t h e e x t e n t t o which s u b j e c t s a p p e a r e d t o b e u s i n g t h i s s t r a t e g y i n A

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t h e r e a c t i o n time and a c c u r a c y t a s k s . We h y p o t h e s i z e d t h a t t h i s s t r a t e g y would b e u t i l i z e d i n t h e r e a c t i o n time b u t n o t the accuracy task. I n t h e accuracy t a s k , t h e s u b j e c t w i l l resolve the l e t t e r s t r i n g t o the deepest l e v e l possible. In t h e r e a c t i o n time t a s k , h a v i n g t h e t a r g e t s p e c i f i e d i n a d v a n c e and h a v i n g t h e t e s t l e t t e r s t r i n g v i s i b l e d u r i n g t h e p r o c e s s i n g i n t e r v a l w i l l a l l o w t h e s u b j e c t t o t e r m i n a t e e a r l y on some catch t r i a l s . To e v a l u a t e t h i s h y p o t h e s i s , t h e l o w e r c a s e l e t t e r s o f t h e a l p h a b e t were g r o u p e d i n t o s i x g r o u p s b a s e d o n t h e s i m i l a r i t y r e s u l t s o f Bouma ( 1 9 7 1 ) . T h i s g r o u p i n g i s g i v e n i n T a b l e 4.1. The r e l a t i o n s h i p between e a c h t a r g e t l e t t e r and t e s t s t r i n g was d e f i n e d i n t e r m s o f t h e number of n o n t a r g e t l e t t e r s i n t h e s t r i n g t h a t were members o f t h e same s e t a s t h e t a r g e t l e t t e r .

P

5501

,!

I 1

I

2

1

3

NUMBER OF SIMILAR NONTARGETS Figure 4.4

R e a c t i o n time i n t h e t a r g e t s e a r c h t a s k a s a f u n c t i o n o f t h e number of s i m i l a r n o n t a r g e t l e t t e r s i n t h e t e s t s t r i n g ( f r o m Massaro e t a l . , 1 9 7 9 ) .


45

e x a m p l e , t h e t e s t s t r i n g l i s v e r would h a v e two l e t t e r s (1 from t h e same s e t a s t h e l e t t e r t , two and J L from same s e t a s and none from t h e same s e t a s 5. F i g u r e s 4.4 and 4.5 g i v e t h i s s i m i l a r i t y a n a l y s i s f o r r e a c t i o n time and accuracy tasks r e s p e c t i v e l y . The results show highly s i g n i f i c a n t e f f e c t s on c a t c h t r i a l s i n t h e r e a c t i o n time t a s k , s u p p o r t i n g t h e i d e a of a f e a t u r e d e t e c t i o n s t r a t e g y i n t h e r e a c t ion t i m e task. The number o f l e t t e r s i n t h e t e s t s t r i n g h a v i n g t h e same o v e r a l l s h a p e a s t h e t a r g e t s h o u l d n o t be i m p o r t a n t on t a r g e t t r i a l s i n t h e r e a c t i o n time t a s k s . The t a r g e t l e t t e r m u s t b e c o m p l e t e l y r e s o l v e d b e f o r e a " y e s " r e s p o n s e c a n be made. If t h e s u b j e c t s s i m p l y r e s p o n d e d " y e s " whenever t h e o v e r a l l s h a p e of t h e t a r g e t was p e r c e i v e d , r e c o g n i t i o n e r r o r s would be h i g h l y For and the

i-)

(v

u,

I

1

1

2

I

3

NUMBER OF SIMILAR NONTARGETS F i g u r e 4.5

Percentage c o r r e c t i n t h e t a r g e t search task a s a f u n c t i o n of t h e number of s i m i l a r n o n t a r g e t l e t t e r s i n t h e t e s t s t r i n g ( f r o m Massaro e t a l . , 1 9 7 9 ) .

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p r o b a b l e . S i n c e a h i g h a c c u r a c y c r i t e r i o n was e n f o r c e d , we would n o t e x p e c t t h e number o f s i m i l a r l y s h a p e d l e t t e r s t o be a c r i t i c a l v a r i a b l e on t a r g e t t r i a l s . A s c a n be s e e n i n F i g u r e 4.4, t h e s i m i l a r i t y v a r i a b l e had no s i g n i f i c a n t e f f e c t o n t a r g e t t r i a l s i n t h e r e a c t i o n time e x p e r i m e n t . I n t h e a c c u r a c y t a s k , p e r f o r m a n c e on c a t c h t r i a l s t e n d e d t o d e c r e a s e w i t h i n c r e a s e s i n t h e number o f s i m i l a r n o n t a r g e t l e t t e r s . I n c o n t r a s t , p e r f o r m a n c e improved somewhat o n t a r g e t t r i a l s w i t h i n c r e a s e s i n t h e number o f s i m i l a r n o n t a r g e t letters. Although t h e s e results were n o t s t a t i s t i c a l l y s i g n i f i c a n t , t h e y show t h a t s i m i l a r i t y may a l s o p l a y a r o l e i n the accuracy t a s k . Although it i s d i f f i c u l t t o compare d i r e c t l y t h e m a g n i t u d e o f t h e e f f e c t s of a c c u r a c y w i t h t h o s e o f r e a c t i o n time, t h e s i m i l a r i t y a n a l y s i s makes s u c h a c o m p a r i s o n more m e a n i n g f u l . The r e a c t i o n time s t u d y i n d i c a t e d s m a l l e f f e c t s of o r t h o g r a p h i c s t r u c t u r e r e l a t i v e t o t h e e f f e c t s of s i m i l a r i t y . The a c c u r a c y study revealed l a r g e e f f e c t s of orthographic s t r u c t u r e r e l a t i v e t o small e f f e c t s of similarity. Contrasting t h e s e two v a r i a b l e s i n e a c h t a s k m i g h t a l l o w a more r e l i a b l e a s s e s s m e n t o f t h e c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e . From t h i s a n a l y s i s it a p p e a r s t h a t o r t h o g r a p h i c s t r u c t u r e p l a y s a l a r g e r r o l e i n t h e a c c u r a c y s t u d y t h a n i t d o e s i n t h e r e a c t i o n time s t u d y . One o f t h e p r i m a r y m o t i v a t i o n s o f t h e p r e s e n t s e t o f e x p e r i m e n t s was t o e x p l o r e t h e d i f f e r e n c e s b e t w e e n t h e s e two t a s k s . Of c o u r s e , i t i s n o t t h e t a s k s t h e m s e l v e s t h a t a r e i n t e r e s t i n g b u t r a t h e r , what t h e y r e v e a l a b o u t t h e p e r c e p t u a l r e c o g n i t i o n of l e t t e r s t r i n g s . The f o l l o w i n g s e t o f e x p e r i m e n t s was a l s o deemed n e c e s s a r y b e c a u s e o f t h e l i m i t a t i o n s i n t h e m a n i p u l a t i o n of o r t h o g r a p h i c s t r u c t u r e i n our p r e v i o u s s t u d i e s . Although w e a t t e m p t e d t o c h o o s e r e g u l a r and i r r e g u l a r s t r i n g s f o r e a c h l e v e l o f h i g h o r low p o s i t i o n a l f r e q u e n c y , we were n o t c o n f i d e n t t h a t w e had It was d i f f i c u l t t o select been c o m p l e t e l y s u c c e s s f u l . regular-low positional-frequency items and i r r e g u l a r - h i g h items. T h i s f o l l o w e d from t h e f a c t t h a t positional-frequency p o s i t i o n a l frequency and our intuitive impression of orthographic regularity might have been highly c o r r e l a t e d . T h e r e f o r e , we may have i n a d v e r t e n t l y c o n f o u n d e d r e g u l a r i t y with p o s i t i o n a l frequency in t h a t t h e high positional-frequency items were more r e g u l a r t h a n t h e low p o s i t i o n a l - f r e q u e n c y items. I t remained a p o s s i b i l i t y t h a t t h e e f f e c t o f p o s i t i o n a l f r e q u e n c y would be e l i m i n a t e d i f w e c o u l d r e g u l a r f o r h i g h and low f i n d items t h a t were e q u a l l y p o s i t i o n a l f r e q u e n c i e s . T h e r e f o r e , we r e f i n e d our d e s c r i p t i o n


47

o f o r t h o g r a p h i c r e g u l a r i t y and c h o s e a new s e t o f items o n t h e b a s i s o f t h e s e r u l e s f o r t h e p r e s e n t e x p e r i m e n t s . The r u l e s a r e p r e s e n t e d i n Appendix 4 . 1 A . I n a d d i t i o n t o s e l e c t i n g new items w e a l s o employed word s t i m u l i i n t h e e x p e r i m e n t s . Krueger (1979) s p e c u l a t e d t h a t a much l a r g e r f a c i l i t a t i o n i n t h e t a r g e t s e a r c h t a s k would be found w i t h words t h a n w i t h pseudowords. By i n c l u d i n g w i t h o u r f o u r c a t e g o r i e s o f m e a n i n g l e s s anagrams t h e words from which t h e y were d e r i v e d , w e c o u l d p r o v i d e a d i r e c t e v a l u a t i o n of t h e f a c i l i t a t i n g e f f e c t s o f word s t r u c t u r e r e l a t i v e t o p o s i t i o n a l f r e q u e n c y and r e g u l a r i t y . W e a l s o saw t h e p o t e n t i a l f o r t e s t i n g a w i d e r r a n g e of f o r m a l d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e i n t h e present experiments. A s indicated e a r l i e r , t h e q u a l i t a t i v e t e s t p r o v i d e d by t h e f a c t o r i a l d e s i g n is l i m i t e d . A good d e s c r i p t i o n of o r t h o g r a p h i c s t r u c t u r e m u s t also describe performance for individual letter strings. T h e r e f o r e , we p l a n n e d t o a n a l y z e p e r f o r m a n c e a s a f u n c t i o n of i n d i v i d u a l l e t t e r s t r i n g s i n t h e p r e s e n t s t u d i e s . These a n a l y s e s would go s i g n i f i c a n t l y beyond t h e q u a l i t a t i v e c o m p a r i s o n s between word, pseudoword, and nonword items o f p r e v i o u s s t u d i e s . A s e c o n d m o t i v a t i o n f o r i n c l u d i n g word items was t h a t a n y d e s c r i p t i o n o f o r t h o g r a p h i c s t r u c t u r e m u s t n o t b e l i m i t e d t o nonword items b u t m u s t a l s o be f u n c t i o n a l f o r word items. If i n some manner l e x i c a l ( i . e . , word) identity o v e r r u l e s o r t h o g r a p h i c s t r u c t u r e , t h e n t h e l a t t e r would n o t b e psychologically relevant i n reading. T h e r e f o r e t h e f i r s t two e x p e r i m e n t s of t h e p r e s e n t s e t o f e x p e r i m e n t s c a n be c o n s i d e r e d t o be a d i r e c t r e p l i c a t i o n of t h e Massaro e t a l . (1979) experiments which h a v e j u s t b e e n d e s c r i b e d . However, t h e p r e s e n t e x p e r i m e n t s i n c l u d e d a new s e t o f items a l o n g w i t h t h e c o r r e s p o n d i n g word s t i m u l i . In t h i s sense, t h e e x p e r i m e n t s conform t o t h e e x p e r i m e n t a l framework g i v e n by Sidman ( 1 9 6 0 ) i n t h a t we a r e b o t h r e p l i c a t i n g and e x t e n d i n g p r e v i o u s e x p e r i m e n t s . F i g u r e 4.6 illustrates the f i v e t y p e s o f i t e m s used i n a l l o f t h e c u r r e n t e x p e r i m e n t s .

STUDY 1:

I N I T I A L REPLICATION

Procedure Two e x p e r i m e n t s were c a r r i e d o u t w i t h 1 4 s u b j e c t s i n e a c h experiment. F i g u r e 4.7 g i v e s a s c h e m a t i c r e p r e s e n t a t i o n of t h e procedures f o r t h e accuracy and RT e x p e r i m e n t s . I n t h e a c c u r a c y e x p e r i m e n t t h e t e s t l e t t e r s t r i n g was p r e s e n t e d f o r a

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s h o r t d u r a t i o n f o l l o w e d i m m e d i a t e l y by a masking s t i m u l u s . The d u r a t i o n o f t h e t e s t item was a d j u s t e d f o r e a c h s u b j e c t i n o r d e r t o o b t a i n a n a v e r a g e of 75% c o r r e c t a c r o s s a l l c o n d i t i o n s i n t h e t a s k . The t a r g e t l e t t e r f o l l o w e d t h e 208 msec masking s t i m u l u s . The s u b j e c t ' s t a s k was t o i n d i c a t e by p r e s s i n g t h e a p p r o p r i a t e b u t t o n w h e t h e r o r n o t t h e t a r g e t l e t t e r was contained i n t h e test l e t t e r s t r i n g . I n t h e RT e x p e r i m e n t t h e t a r g e t l e t t e r was p r e s e n t e d f o r 500 msec f o l l o w e d by a 1 sec b l a n k p e r i o d . The t e s t s t r i n g was t h e n p r e s e n t e d and r e m a i n e d on u n t i l t h e s u b j e c t r e s p o n d e d " y e s " o r "no" w i t h r e s p e c t t o whether or n o t t h e t a r g e t l e t t e r o c c u r r e d i n t h e t e s t s t r i n g . A r e a s o n a b l e amount o f p r a c t i c e was g i v e n on b o t h t a s k s . The t e s t items were s i x - l e t t e r s t r i n g s c o n s i s t i n g o f 4 0 words and 160 anagrams c r e a t e d by t h e f a c t o r i a l c o m b i n a t i o n o f h i g h or low positional-frequency and regular or irregular

I words

I I

winter charge turned (1293)

Regular

Positional Frequency High

Low

triwen chager drunet (1438)

trewin greach tredun (540)

wrntei ahcger rdnuet (1421)

rntewi hreagc edtrnu (526)

Orthographic Regularity

I

Figure 4.6

I

The f i v e t y p e s o f i t e m s and e x a m p l e s of e a c h t y p e used i n t h e e x p e r i m e n t s . The number i n e a c h c e l l i s t h e a v e r a g e summed s i n g l e - l e t t e r positional f r e q u e n c y f o r t h a t item t y p e ( b a s e d on t h e Mayzner & T r e s s e l t , 1965, c o u n t s ) .


49

s t r u c t u r e . On a n y t r i a l , any o f t h e f i v e t y p e s of s t r i n g s The t e s t c o u l d be p r e s e n t e d a s e i t h e r a c a t c h o r t a r g e t t r i a l . s t r i n g s a r e p r e s e n t e d i n Appendix 4 . 1 B . The d e t a i l s o f t h e method, p r o c e d u r e , and r e s u l t s o f t h e two t a s k s a r e p r e s e n t e d i n Appendix 4 . 1 . Orthographic S t r u c t u r e F i g u r e s 4.8 and 4.9 p r e s e n t t h e r e s u l t s from t h e a c c u r a c y RT t a s k s a s a function of t h e f i v e classes o f items. P e r f o r m a n c e i n t h e a c c u r a c y t a s k depended g r e a t l y on t h e s t r u c t u r e o f t h e t e s t s t r i n g . Words were r e c o g n i z e d 1 2 % more o f t e n t h a n t h e b e s t r e g u l a r h i g h items. The r e g u l a r s t r i n g s w e r e j u d g e d 8 % more a c c u r a t e l y t h a n t h e i r r e g u l a r strings. A c c u r a c y was 5 % h i g h e r f o r h i g h p o s i t i o n a l - f r e q u e n c y and

PRECUE RT Target Letter

+- : I-

500

Test Display

II 1000

POSTCUE ACCURACY Test

Figure 4.7

Mask

Target Letter

Schematic r e p r e s e n t a t i o n s of t h e p r e c u e time and p o s t c u e a c c u r a c y e x p e r i m e n t s .

reaction

CHAPTER 4

50

s t r i n g s t h a n f o r low p o s i t i o n a l - f r e q u e n c y s t r i n g s . A l l of t h e s e r e s u l t s were s t a t i s t i c a l l y s i g n i f i c a n t . The d e t a i l e d r e s u l t s and t h e s t a t i s t i c a l a n a l y s e s a r e p r e s e n t e d i n Appendix 4.1. I n t h e RT t a s k , r e a c t i o n times t o words were o n l y 7 msec f a s t e r t h a n r e a c t i o n times t o r e g u l a r - h i g h anagrams. R e g u l a r items were j u d g e d 2 3 msec f a s t e r t h a n i r r e g u l a r items, w h e r e a s h i g h p o s i t i o n a l - f r e q u e n c y items were r e s p o n d e d t o o n l y 4 msec f a s t e r t h a n low p o s i t i o n a l - f r e q u e n c y items. Only t h e e f f e c t o f r e g u l a r i t y was s t a t i s t i c a l l y s i g n i f i c a n t . The d e t a i l e d r e s u l t s and s t a t i s t i c a l a n a l y s e s a r e p r e s e n t e d i n Appendix 4.1. The h i g h l y s i g n i f i c a n t e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e on r e s p o n s e a c c u r a c y and t h e r e l a t i v e l y m i n o r , and f o r t h e m o s t p a r t , n o n s i g n i f i c a n t e f f e c t s of o r t h o g r a p h i c s t r u c t u r e on r e a c t i o n time p r o v i d e a d i r e c t r e p l i c a t i o n o f o u r p r e v i o u s

1

I

I

I

R-H

R-L

I-H

I-L

50

WORD

Figure 4.8

P e r c e n t a g e c o r r e c t a s a f u n c t i o n of d i s p l a y t y p e f o r t a r g e t and c a t c h t r i a l s i n t h e p o s t c u e a c c u r a c y t a s k of S t u d y 1.


51

work. These r e s u l t s u n d e r s c o r e the reliability of t h e r e g u l a r i t y and p o s i t i o n a l - f r e q u e n c y e f f e c t s on a c c u r a c y by d e m o n s t r a t i n g a g e n e r a l i z a t i o n t o b o t h a new s a m p l e o f s u b j e c t s and a new s a m p l e of s t i m u l u s items ( C l a r k , 1 9 7 3 ) . N e i t h e r r e g u l a r i t y nor p o s i t i o n a l f r e q u e n c y , however, a p p e a r s t o b e s u f f i c i e n t t o a c c o u n t f o r t h e s t r o n g a c c u r a c y a d v a n t a g e found f o r words. The i s s u e o f w h e t h e r or n o t o r t h o g r a p h i c s t r u c t u r e r a t h e r t h a n l e x i c a l i d e n t i t y c a n a c c o u n t for t h e word a d v a n t a g e w i l l b e d e l a y e d u n t i l a more d e t a i l e d d i s c u s s i o n and e v a l u a t i o n of o r t h o g r a p h i c s t r u c t u r e is p r e s e n t e d . Similarity Effects To t e s t f o r t h e e f f e c t s o f s i m i l a r i t y between t h e t a r g e t l e t t e r s o u g h t i n a d i s p l a y and t h e l e t t e r s a c t u a l l y o c c u r r i n g

Y

I

w

E 600 I-

5

P

Figure 4.9

550-

R e a c t i o n time and p e r c e n t a g e c o r r e c t a s a f u n c t i o n of d i s p l a y t y p e for t a r g e t and c a t c h t r i a l s i n t h e p r e c u e r e a c t i o n t i m e t a s k o f S t u d y 1.

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52

Table 4.2

Target a

For e a c h o f t h e 26 l e t t e r s i s l i s t e d t h e o t h e r l e t t e r s i n t h e a l p h a b e t t h a t were e r r o n e o u s l y i d e n t i f i e d a s t h a t l e t t e r more t h a n 5% o f t h e t i m e ( f r o m Bouma, 1 9 7 1 ) .

Similar Nontarget L e t t e r s c , e l m , n, 0 , s, x , z

Target n

Similar Nontarget L e t t e r s a, e l s, u, x

C

0

P

4

i.

1, t

V

W

j

1

W

V

k

t, x

X

Y

V

i n t h e d i s p l a y , t h e d a t a were p o o l e d a c r o s s a l l f i v e d i s p l a y t y p e s and r e p a r t i t i o n e d . The b a s i s f o r t h i s r e p a r t i t i o n i n g was t h e c l a s s i f i c a t i o n of each t r i a l ' s t a r g e t l e t t e r according t o which l e t t e r s a r e l i k e l y t o b e s e e n a s v e r y s i m i l a r t o t h e target. The c l a s s i f i c a t i o n was d e r i v e d from t h e l o w e r c a s e single-letter c o n f u s a b i l i t y s t u d y o f Bouma ( 1 9 7 1 ) shown i n We c o u n t e d a n o n t a r g e t l e t t e r a s s i m i l a r t o t h e table 2.4. target l e t t e r if the nontarget l e t t e r was e r r o n e o u s l y i d e n t i f i e d a s t h e t a r g e t more t h a n 5% o f t h e t i m e i n Bouma's s t u d y . T a b l e 4.2 presents the similarity classification a c c o r d i n g t o t h i s a n a l y s i s . For e x a m p l e , g i v e n t h e t a r g e t


53

l e t t e r &, t h e s i m i l a r n o n t a r g e t l e t t e r s a r e k, E, a n d u. T h i s m ean s t h a t t h e s t i m u l u s l e t t e r s k t k, p , a n d 2 were i d e n t i f i e d a s b m o r e t h a n 5 % o f t h e t i m e i n Bouma's s t u d y . Each u n i q u e t r i a l i n o u r t a r g e t s e a r c h t a s k w as t h e n d e s c r i b e d b y t h e number o f n o n t a r g e t l e t t e r s i n t h e d i s p l a y t h a t were similar to the target according to this classification. Roughly 46, 33, 1 3 , and 7 % of e a c h s u b j e c t ' s t r i a l s f e l l i n t o t h e c a t e g o r i e s z e r o , one, two, and t h r e e similar letters (other than the target letter i t s e l f ) , respectively. F i g u r e s 4.10 and 4 . 1 1 p r e s e n t t h e a c c u r a c y an d r e a c t i o n t i m e r e s u l t s a s a f u n c t i o n o f t h e number o f s i m i l a r n o n t a r g e t l e t t e r s i n t h e d i s p l a y . T a r g e t v e r s u s c a t c h t r i a l s is t h e curve parameter i n t h e figures. In t h e accuracy t a s k , accuracy i n c r e a s e d w i t h i n c r e a s e s i n t h e number o f s i m i l a r n o n t a r g e t

100

I

1

I

I

90

k

Ya

8 0

B

80

70

I2k 60

50

1

I

1

0

1

2

L

3

NUMBER OF SIMILARNONTARGETS F i g u r e 4.10

P e r c e n t a g e c o r r e c t a s a f u n c t i o n o f t h e number o f similar nontarget letters in the test s t r i n g s i n t h e a c c u r a c y e x p e r i m e n t o f S t u d y 1.

54

CHAPTER 4

l e t t e r s o n t a r g e t t r i a l s and d e c r e a s e d o n c a t c h t r i a l s . The l a r g e s i m i l a r i t y e f f e c t s i n t h e accuracy t a s k c o n t r a s t with t h e The s m a l l e r e f f e c t s o f Massaro e t a l . shown i n F i g u r e 4 . 5 . p r e s e n t a n a l y s i s may h a v e p r o v i d e d a more s e n s i t i v e t e s t o f s i m i l a r i t y t h a n t h e Massaro e t a l . a n a l y s i s s i n c e t h e c o n f u s i o n s e t s were computed i n a more p r e c i s e manner. In p a r t i c u l a r , the present analysis allows for asymmetric is considered t o be a s i m i l a r nontarget c o n f u s i o n s . Although l e t t e r g i v e n t h e t a r g e t l e t t e r d, 9, o r 2 , t h e o n l y s i m i l a r is t h e l e t t e r 0. In nontarget l e t t e r for the t a r g e t l e t t e r t h e r e a c t i o n t i m e t a s k , r e a c t i o n time i n c r e a s e d w i t h i n c r e a s e s i n t h e number o f s i m i l a r t a r g e t l e t t e r s o n c a t c h t r i a l s b u t d i d n o t c h a n g e much o n t a r g e t t r i a l s . T h i s r e s u l t p r o v i d e s a d i r e c t r e p l i c a t i o n o f t h e s i m i l a r i t y a n a l y s i s i n t h e Massaro e t a l . s t u d y shown i n F i g u r e 4.4.

c

e,

700r---

650

th rEl +--+Target

500

450

1

2

3

NUMBER OF SIMILAR NONTARGETS F i g u r e 4.11

R e a c t i o n time a s a f u n c t i o n o f t h e number similar nontarget l e t t e r s i n the t e s t s t r i n g t h e r e a c t i o n t i m e e x p e r i m e n t o f S t u d y 1.

of in


55

Target-Catch Differences Accuracy was 1 2 % h i g h e r f o r c a t c h t r i a l s t h a n f o r t a r g e t t r i a l s and t h i s e f f e c t i n t e r a c t e d w i t h d i s p l a y t y p e s ( c f . Figure 4.8). R e a c t i o n times were 47 msec s l o w e r f o r c a t c h t r i a l s than f o r t a r g e t t r i a l s ( c f . Figure 4.9). The r e s u l t s show t h a t s u b j e c t s i n a n a c c u r a c y t a s k t e n d t o be more a c c u r a t e on c a t c h t r i a l s t h a n on t a r g e t t r i a l s w h e r e a s t h e y t e n d t o t a k e l o n g e r on c a t c h t r i a l s i n t h e r e a c t i o n time e x p e r i m e n t . Given t h a t t h e s e r e s u l t s d o n o t come from t h e same e x p e r i m e n t , t h e y c a n n o t be i n t e r p r e t e d i n t e r m s o f a s p e e d a c c u r a c y t r a d e - o f f . RT task was a l s o However, r e s p o n s e a c c u r a c y in the s i g n i f i c a n t l y higher f o r catch than f o r t a r g e t t r i a l s (Figure 4.9) and t h i s r e s u l t m i g h t a c c o u n t f o r t h e l o n g e r r e a c t i o n times on c a t c h t r i a l s i n t h e r e a c t i o n t i m e t a s k . A central q u e s t i o n r a i s e d by t h i s s t u d y c o n c e r n s t h e n a t u r e o f t h e s i m i l a r i t i e s and t h e d i f f e r e n c e s between a c c u r a c y paradigms. Results from a c c u r a c y and and r e a c t i o n time r e a c t i o n time s t u d i e s a r e f r e q u e n t l y r e g a r d e d a s c o n v e r g e n t i n d i c a t i o n s of common perceptual processing. Systematic d i f f e r e n c e s between t h e a c c u r a c y and RT e f f e c t s would s u g g e s t t h a t p e r c e p t u a l p r o c e s s e s may n o t be t h e same i n b o t h c a s e s . Thus, two i m p o r t a n t q u e s t i o n s a r e w h e t h e r o r n o t a c c u r a c y and r e a c t i o n time r e s u l t s c a n be p r e d i c t e d from a common p r o c e s s i n g model, and i f s o , how t h e d i f f e r e n t s t i m u l u s e n v i r o n m e n t s o f t h e a c c u r a c y and r e a c t i o n time t a s k s c a u s e t h e o b s e r v e d d i f f e r e n c e s i n t h e m a g n i t u d e of t h e e f f e c t s . The a c c u r a c y and t h e r e a c t i o n time t a s k s w i l l be e v a l u a t e d i n t h e framework o f t h e information processing model. In order to better u n d e r s t a n d t h e e f f e c t s o f t a r g e t and c a t c h t r i a l s and t o b e t t e r e x p l i c a t e o u r i n t e r p r e t a t i o n of t h e p r o c e s s e s i n t h e a c c u r a c y and r e a c t i o n t i m e t a s k s , we w i l l p r e s e n t a n i n f o r m a t i o n p r o c e s s i n g a n a l y s i s o f p e r f o r m a n c e i n t h e a c c u r a c y and r e a c t i o n time t a s k s .

INFORMATION PROCESSING MODEL

With t h e r e g i s t r a t i o n of a l e t t e r s t r i n g a s a n image upon the retina, sensory transduction begins. Features are extracted simultaneously ( i n parallel) from e a c h l e t t e r p o s i t i o n i n t h e d i s p l a y and a r e e n t e r e d i n t o p r e p e r c e p t u a l visual storage. Feature e x t r a c t i o n i s a temporally extended p r o c e s s so t h a t t h e c o n t e n t s of p r e p e r c e p t u a l v i s u a l s t o r a g e

CHAPTER 4

b u i l d up o v e r t i m e . C o n c u r r e n t w i t h t h e e s t a b l i s h m e n t o f t h e new c o n t e n t s o f p r e p e r c e p t u a l v i s u a l s t o r a g e , t h e p r i m a r y recognition process transforms the current c o n t e n t s of p r e p e r c e p t u a l v i s u a l s t o r a g e i n t o s y n t h e s i z e d v i s u a l memory. The c o n t e n t s o f s y n t h e s i z e d v i s u a l memory a r e c o n t i n u a l l y m o n i t o r e d by a d e c i s i o n p r o c e s s w h i c h , i n t h e case o f t h e p r e c u e t a r g e t s e a r c h t a s k , e n d e a v o r s t o match t h e t a r g e t w i t h t h e f r e s h l y r e s o l v e d and c o n t i n u o u s l y u p d a t e d l e t t e r s t r i n g i n synthesized visual memory, as in Turvey's (1973) c o n c u r r e n t - c o n t i n g e n t model. it is To d e r i v e s p e c i f i c p r e d i c t i o n s from t h e model, n e c e s s a r y t o make a few assumptions about t h e primary r e c o g n i t i o n p r o c e s s and t h e d e c i s i o n p r o c e s s . Experimental s u p p o r t f o r t h e s e a s s u m p t i o n s p r e v i o u s l y h a s been d e m o n s t r a t e d ( M a s s a r o , 1 9 7 9 a ) . The f i r s t a s s u m p t i o n i s t h a t knowledge of orthographic s t r u c t u r e c o n t r i b u t e s an independent source of knowledge a b o u t t h e l e t t e r s t r i n g . A c c o r d i n g l y , e x p e r i e n c e d r e a d e r s w i l l be b i a s e d t o i n t e r p r e t t h e l e t t e r s t r i n g a s o n e t h a t is o r t h o g r a p h i c a l l y s t r u c t u r e d . T h e r e f o r e , t o t h e e x t e n t t h a t t h e l e t t e r s b e i n g r e s o l v e d from p r e p e r c e p t u a l v i s u a l s t o r a g e form w e l l - s t r u c t u r e d l e t t e r s e q u e n c e s , t h e y may b e r e s o l v e d w i t h fewer f e a t u r e s o r b e f o r e a l l f e a t u r e s h a v e been extracted. In contrast, a poorly-structured string w i l l r e q u i r e n e a r l y complete f e a t u r a l information f o r r e c o g n i t i o n b e c a u s e o r t h o g r a p h i c knowledge w i l l p r o v i d e no a d d i t i o n a l a s s i s t a n c e . T h u s , t h e c o n t e n t s o f s y n t h e s i z e d v i s u a l memory a r e e s t a b l i s h e d by p r i m a r y r e c o g n i t i o n more q u i c k l y and accurately for well-structured than f o r poorly-structured strings. The s e c o n d a s s u m p t i o n is r e l a t e d t o t h e d e c i s i o n a l g o r i t h m i n t h e t a r g e t s e a r c h t a s k . When t h e t a r g e t l e t t e r is known i n advance, t h e d e c i s i o n process monitors t h e continuously emerging c o n t e n t s o f s y n t h e s i z e d v i s u a l memory s e e k i n g a match All letter positions are monitored t o the target. i n d e p e n d e n t l y and i n p a r a l l e l . The d e c i s i o n p r o c e s s m a i n t a i n s two c r i t e r i a o r d e c i s i o n a x e s , a n a l o g o u s t o t h e model o f memory s e a r c h d e v e l o p e d by A t k i n s o n and J u o l a ( 1 9 7 4 ) . Whenever a l e t t e r p o s i t i o n exceeds t h e f i r s t c r i t e r i o n i n resemblance t o t h e t a r g e t , a match is assumed t o h a v e been f o u n d , p r o c e s s i n g t e r m i n a t e s , and a p o s i t i v e r e s p o n s e is e x e c u t e d . Whenever a l e t t e r p o s i t i o n is s u f f i c i e n t l y d i s s i m i l a r t o t h e t a r g e t t o e x c e e d t h e second c r i t e r i o n , t h e l e t t e r i s c l a s s i f i e d a s a n o t y e t been r e s o l v e d f o i l . Letter p o s i t i o n s t h a t have s u f f i c i e n t l y t o be c l a s s i f i e d a s t a r g e t o r f o i l c o n t i n u e t o be r e s o l v e d u n t i l t h e y c a n be c l a s s i f i e d or u n t i l f u r t h e r


57

When a l l l e t t e r p o s i t i o n s h a v e r e s o l u t i o n is n o t p o s s i b l e . been c l a s s i f i e d a s f o i l s , a n e g a t i v e r e s p o n s e i s e x e c u t e d . I f t h e v i s u a l s t i m u l u s i s impoverished s o t h a t f u l l r e s o l u t i o n o f a l l l e t t e r p o s i t i o n s is n o t p o s s i b l e , a d e c i s i o n i s f o r c e d when no f u r t h e r r e s o l u t i o n is p o s s i b l e . Given t h a t the f u l l y resolved or c l e a r l y " s e e n " l e t t e r s h a v e been c l a s s i f i e d as f o i l s , a g u e s s r e s p o n s e m u s t be e x e c u t e d based upon the remaining "unseen" letters. The observer's p r o b a b i l i t y o f g u e s s i n g t h a t one of t h e u n r e s o l v e d l e t t e r s is a t a r g e t i s a j o i n t f u n c t i o n of a p r i o r i e x p e c t a t i o n s t h a t any g i v e n l e t t e r w i l l be a t a r g e t and t h e number of u n r e s o l v e d letters. T h e s e e x p e c t a t i o n s a r e d e r i v e d from i n s t r u c t i o n s and past experience. For t h e p r e c u e RT t a s k , t h e f o l l o w i n g p r e d i c t i o n s a l s o f o l l o w d i r e c t l y from t h e model. D e c i s i o n time i s a d i r e c t f u n c t i o n of t h e r e s o l u t i o n t i m e of t h e s t i m u l u s s t r i n g and t h e r e f o r e i s i n f l u e n c e d by t h e o r t h o g r a p h i c r e d u n d a n c i e s t h a t can be e x p l o i t e d i n t h e stimulus. The t i m e t o c o r r e c t l y i d e n t i f y a t a r g e t i n t h e l e t t e r s t r i n g is a f u n c t i o n s o l e l y of on t h e t h e time r e q u i r e d t o r e s o l v e t h e t a r g e t and w i l l , a v e r a g e , be s h o r t e r t h a n t h e time r e q u i r e d t o e x h a u s t i v e l y c l a s s i f y a l l l e t t e r s a s f o i l s on a c a t c h t r i a l . Identification time f o r t h e t a r g e t l e t t e r i s i n f l u e n c e d by t h e o r t h o g r a p h i c c o n s t r a i n t s among t h e l e t t e r s i n t h e c a t c h s t r i n g . The e m p h a s i s o n a c c u r a c y i n t h e RT t a s k d i s p o s e s t h e o b s e r v e r t o m a i n t a i n s t r i c t c r i t e r i a w h i c h , f o r t h e most p a r t , p r e c l u d e errors. I n a p o s t c u e t a s k , r e c o g n i t i o n and d e c i s i o n p r o c e s s e s a n a l o g o u s t o t h o s e f o r t h e p r e c u e t a s k a r e assumed t o o p e r a t e , e x c e p t t h a t t h e c o n t e n t s of s y n t h e s i z e d v i s u a l memory m u s t b e m a i n t a i n e d a w a i t i n g t h e a r r i v a l and r e c o g n i t i o n o f t h e t a r g e t l e t t e r . The s t i m u l u s l e t t e r s t r i n g i s r e s o l v e d a s f u l l y a s t h e combined v i s u a l i n f o r m a t i o n and o r t h o g r a p h i c s t r u c t u r e a l l o w and i s r e t a i n e d a w a i t i n g p r e s e n t a t i o n of t h e t a r g e t . Once t h e t a r g e t is i d e n t i f i e d , i t is compared w i t h however much o f t h e l e t t e r s t r i n g was r e s o l v e d . I f a match i s f o u n d , a p o s i t i v e r e s p o n s e i s e x e c u t e d . F o l l o w i n g t h e a r g u m e n t of Thompson and assumed t h a t the exact f e a t u r a l Massaro (1973), it is s i m i l a r i t y of t h e unresolved l e t t e r s t o t h e t a r g e t l e t t e r is n o t d i r e c t l y a v a i l a b l e t o t h e d e c i s i o n p r o c e s s and d o e s n o t influence the guess probability. Orthographic structure i n f l u e n c e s a c c u r a c y f o r b o t h t a r g e t and c a t c h t r i a l s b e c a u s e i t i n f l u e n c e s t h e number of l e t t e r s t h a t a r e a c c u r a t e l y p e r c e i v e d . I t may seem s u r p r i s i n g t h a t t h e Thompson and Massaro ( 1 9 7 3 ) and t h e Massaro e t a l . ( 1 9 7 9 ) s t u d i e s r e v e a l e d no

CHAPTER 4

s i g n i f i c a n t e f f e c t s of l e t t e r s i m i l a r i t y . Even i f f e a t u r a l i n f o r m a t i o n i s n o t t r a n s m i t t e d t o s y n t h e s i z e d v i s u a l memory we would e x p e c t i n c o r r e c t s y n t h e s e s t o be s i m i l a r t o t h e t e s t l e t t e r . For e x a m p l e , g i v e n t h e t e s t l e t t e r 0, we would e x p e c t t h a t r e c o g n i t i o n e r r o r s w i l l b e more l i k e l y t o c o n s i s t o f c and e t h a n I and 2. One f a c t o r t h a t may work a g a i n s t o b s e r v a t i o n of t h i s phenomenon may be t h a t t h e t e s t d i s p l a y was f o l l o w e d by a masking s t i m u l u s i n t h e a c c u r a c y t a s k and t h e r e is now some e v i d e n c e t h a t f e a t u r e s o f t h e mask c o n t r i b u t e t o p e r c e p t u a l memory o f t h e t e s t (Kallman & Massaro, 1 9 7 9 ; S m i t h , H a v i l a n d , R e d e r , B r o w n e l l , & Adams, 1 9 7 6 ) . G i v e n t h e c o n t r i b u t i o n o f t h e mask, i n c o r r e c t r e s p o n s e s m i g h t be more e a s i l y p r e d i c t e d by t h e f e a t u r e s o f t h e mask t h a n t h e f e a t u r e s o f t h e t e s t . A s e c o n d reason f o r observing small s i m i l a r i t y e f f e c t s i n t h e accuracy s t u d i e s is t h a t t h e a c c u r a c y s t u d i e s w i t h l e t t e r s t r i n g s employ a f o r c e d - c h o i c e r e s p o n s e s i t u a t i o n s o t h a t t h o s e few t r i a l s t h a t involve i n c o r r e c t perceptual syntheses a r e u n l i k e l y t o agree with t h e i n c o r r e c t response a l t e r n a t i v e . The s y s t e m a t i c l e t t e r confusions u s u a l l y found i n s i n g l e - l e t t e r recognition s t u d i e s c o u l d depend on a n open-ended s e t o f l e t t e r r e s p o n s e also possible t o observe a l t e r n a t i v e s . However, i t is s i g n i f i c a n t s i m i l a r i t y e f f e c t s a s i n t h e present accuracy study ( c f . Figure 4.18). The p a t t e r n of t h e s e r e s u l t s i s c o n s i s t e n t w i t h t h e i d e a t h a t s i m i l a r l e t t e r s may b e m i s t a k e n l y i d e n t i f i e d a s t h e t a r g e t . Hence, a c c u r a c y on t a r g e t t r i a l s i n c r e a s e s w i t h t h e number of s i m i l a r l e t t e r s t o t h e t a r g e t i n t h e t e s t s t r i n g , b u t a c c u r a c y o n c a t c h t r i a l s d e c r e a s e s a s t h e number of s i m i l a r l e t t e r s t o t h e t a r g e t is i n c r e a s e d . I t i s p o s s i b l e t o q u a n t i f y t h e p r o c e s s i n g model i n o r d e r t o d e s c r i b e t h e q u a n t i t a t i v e r e s u l t s of t h e t a r g e t s e a r c h t a s k . I n a n a c c u r a c y t a s k , i t i s assumed t h a t t h e l e t t e r s t r i n g i s perceived ( i . e . , resolved) a s f u l l y a s possible. R e s o l u t i o n of the display is a d i r e c t f u n c t i o n of b o t h t h e f e a t u r a l i n f o r m a t i o n a v a i l a b l e and t h e o r t h o g r a p h i c s t r u c t u r e o f t h e t e s t s t r i n g . S i n c e e a c h o f t h e f o u r t y p e s of m e a n i n g l e s s l e t t e r s t r i n g s was composed by making anagrams of a s i x - l e t t e r word, t h e same l e t t e r s were p r e s e n t a c r o s s t h e f i v e d i s p l a y . t y p e s . The f i v e d i s p l a y t y p e s were a l s o p r e s e n t e d a t t h e same i n t e n s i t y and d u r a t i o n s . Therefore, t h e featural information may be assumed to be constant across the display t y p e s . However, t h e d i s p l a y t y p e s d i f f e r w i t h r e s p e c t t o o r t h o g r a p h i c s t r u c t u r e and t h e s e d i f f e r e n c e s c a n a c c o u n t f o r t h e performance d i f f e r e n c e s a c r o s s t h e f i v e d i s p l a y t y p e s . T h e r e f o r e , t h e number o f l e t t e r s r e s o l v e d , R , w i l l depend on the d i s p l a y type.


59

I t is necessary t o describe a decision r u l e t h a t allows t h e s u b j e c t t o s e l e c t a " y e s " o r "no" r e s p o n s e . I t i s assumed t h a t i f one of t h e r e s o l v e d l e t t e r s is i d e n t i c a l t o t h e t a r g e t , a " y e s " r e s p o n s e is e x e c u t e d . I f t h e t a r g e t l e t t e r is n o t c o n t a i n e d i n t h e s e t of r e s o l v e d l e t t e r s , a " y e s " r e s p o n s e i s a f u n c t i o n o f t h e number o f u n r e s o l v e d l e t t e r s and t h e r e a d e r ' s E , t h a t some l e t t e r i n t h e s i x - l e t t e r s t r i n g w i l l expectation, be i d e n t i c a l t o t h e t a r g e t . Since E is the expectation for a whole s i x - l e t t e r t e s t s t r i n g c o n t a i n i n g t h e t a r g e t , t h e n E/6 i s t h e e x p e c t a t i o n t h a t any s i n g l e l e t t e r i n t h e t e s t s t r i n g is identical t o the target. The e x p e c t a t i o n v a l u e E would be some f u n c t i o n o f i n s t r u c t i o n s , f e e d b a c k , and how o f t e n t h e t a r g e t Therefore, the l e t t e r is a c t u a l l y s e e n i n t h e t e s t s t r i n g . p r o b a b i l i t y o f a " y e s " r e s p o n s e t o t h e t a r g e t t r i a l i s g i v e n by Equation 1 f o r l e t t e r s t r i n g s of l e n g t h 6.

The l e f t - h a n d t e r m of E q u a t i o n 1 i n d i c a t e s t h a t R - s i x t h s o f t h e time one o f t h e r e s o l v e d l e t t e r s w i l l be i d e n t i c a l t o t h e t a r g e t and t h e o b s e r v e r w i l l r e s p o n d " y e s " w i t h p r o b a b i l i t y o n e . On t h e r e m a i n i n g t r i a l s , 1 - R/6, t h e t a r g e t was n o t r e s o l v e d and t h e o b s e r v e r g u e s s e s w i t h p r o b a b i l i t y E / 6 w e i g h t e d by t h e number o f u n r e s o l v e d l e t t e r s ( 6 - R ) . For c a t c h t r i a l s , t h e o b s e r v e r w i l l n e v e r f i n d t h e t a r g e t a n d , t h e r e f o r e , i s i n a n i m p e r f e c t knowledge s t a t e u n l e s s h e o r s h e r e s o l v e s a l l o f t h e l e t t e r s . T h e r e f o r e , t h e l i k e l i h o o d of a " y e s " r e s p o n s e is s i m p l y t h e o b s e r v e r ' s e x p e c t a t i o n t h a t a g i v e n t e s t l e t t e r i s a t a r g e t l e t t e r , E/6, w e i g h t e d by t h e number of u n r e s o l v e d t a r g e t l e t t e r s , 6 - R: P(YeslCatch) = (6

-

R) x

(E/6)

Of c o u r s e , t h e l i k e l i h o o d o f b e i n g c o r r e c t o n c a t c h t r i a l s t h e complement o f E q u a t i o n ( 2 ) : P(No1Catch) = 1

-

[(6

-

R) x

(E/6)]

(2)

is

(3)

The model was a p p l i e d t o t h e r e s u l t s o f t h e a c c u r a c y experiment. The model was f i t t o t h e 1 0 a v e r a g e r e s p o n s e a c c u r a c i e s ( t h e f i v e d i s p l a y t y p e s on t a r g e t p r e s e n t t r i a l s and t h e f i v e d i s p l a y t y p e s o n c a t c h o r t a r g e t a b s e n t t r i a l s ) . The f i t was o b t a i n e d u s i n g a l e a s t - s q u a r e s parameter e s t i m a t i o n r o u t i n e ( C h a n d l e r , 1 9 6 9 ) . S i x p a r a m e t e r s w e r e e s t i m a t e d from t h e d a t a : one e x p e c t a t i o n p a r a m e t e r , E , and a n e s t i m a t e o f t h e

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number o f l e t t e r s f u l l y r e s o l v e d , R , f o r e a c h o f t h e f i v e display types. The o b t a i n e d f i t was q u i t e good; t h e r o o t mean s q u a r e d d e v i a t i o n was o n l y 1 . 3 % . A l t h o u g h i t is d i f f i c u l t t o a p p r e c i a t e t h e q u a n t i t a t i v e g o o d n e s s - o f - f i t f o r s u c h a model estimating s i x parameters f o r 10 d a t a p o i n t s , t h e obtained parameter v a l u e s nonetheless a r e revealing. The s u b j e c t s were c l e a r l y i n f o r m e d of t h e e q u a l number o f t a r g e t and c a t c h t r i a l s i n t h e e x p e r i m e n t and t h e r e f o r e , t h e y s h o u l d have a d o p t e d a n .5. However, t h e o b s e r v e d g r e a t e r a c c u r a c y f o r E-value of c a t c h t r i a l s would a p p e a r t o s u g g e s t a b i a s t o w a r d "no" r e s p o n s e s o r a n a p p a r e n t E-value r a t h e r c l o s e t o z e r o . In f a c t , t h e e s t i m a t e d E-value was . 4 6 s u g g e s t i n g t h a t t h e s u b j e c t s p o s s e s s e d a t most a v e r y s l i g h t b i a s . The s t r o n g i m b a l a n c e between c a t c h a c c u r a c y and t a r g e t a c c u r a c y i s a l o g i c a l c o n s e q u e n c e of t h e model even when l i t t l e o r no b i a s is present. A l t h o u g h t h e r e a r e no a p r i o r i v a l u e s o f t h e R p a r a m e t e r s t o which t h e e s t i m a t e s may b e c o m p a r e d , t h e o b t a i n e d estimates f o r R provide a reasonable s c a l i n g f o r the f i v e types o f items. T h e s e v a l u e s a r e shown i n T a b l e 4.3 a s Postcue (Study 1 ) . While t h e s p e c i f i c a t i o n o f a q u a n t i t a t i v e model p r e d i c t i n g r e a c t i o n times is c o n s i d e r a b l y more complex, it nonetheless s t e m s d i r e c t l y from t h e a b o v e i n f o r m a t i o n p r o c e s s i n g a n a l y s i s . The r e a c t i o n t i m e on a t a r g e t t r i a l i s t h e s u m o f t h e t i m e needed t o r e s o l v e t h e t a r g e t l e t t e r i n t h e l e t t e r s t r i n g p l u s t h e time needed t o i n i t i a t e and e x e c u t e t h e c o r r e c t r e s p o n s e . The r e s o l u t i o n time f o r t h e t a r g e t l e t t e r i s a f u n c t i o n o f i t s v i s u a l p r o p e r t i e s and o f t h e o r t h o g r a p h i c s t r u c t u r e o f t h e l e t t e r s t r i n g i n which t h e t a r g e t o c c u r s . Since orthographic s t r u c t u r e a f f e c t s t h e t i m e needed t o r e s o l v e t h e l e t t e r s t r i n g , o r t h o g r a p h i c s t r u c t u r e is a p a r a m e t e r o f t h e d i s t r i b u t i o n o f the reaction times. The e x p e c t e d v a l u e o f t h i s d i s t r i b u t i o n (Response p l u s a c o n s t a n t g i v e s a v e r a g e RT f o r t a r g e t t r i a l s . i n i t i a t i o n and e x e c u t i o n t i m e is assumed t o b e c o n s t a n t o r a t l e a s t d i s t r i b u t e d independently of t h e e f f e c t of primary interest.) For c a t c h t r i a l s , t h e RT i s t h e s u m o f a c o n s t a n t time f o r r e s p o n s e e x e c u t i o n p l u s t h e maximum time needed t o c l a s s i f y a l l l e t t e r s a s f o i l s . C l a s s i f i c a t i o n t i m e i s b a s e d upon t h e j o i n t d i s t r i b u t i o n o f completion t i m e s f o r e a c h o f t h e f o i l s on t h e n o n t a r g e t t r i a l s . These d i s t r i b u t i o n s have a s p a r a m e t e r s t h e similarity of the f o i l t o the t a r g e t , other visual properties which a f f e c t t h e o v e r a l l e a s e of r e s o l v i n g the f o i l , the i n f l u e n c e o f o r t h o g r a p h i c s t r u c t u r e , and f i n a l l y t h e s u b j e c t ' s c r i t e r i o n f o r a v o i d i n g f a l s e a l a r m s . Having o u t l i n e d t h e model


T a b l e 4.3

61

E s t i m a t e s o f p e r c e p t u a l r e s o l u t i o n ( R ) and a p r i o r i expectation (E) of t h e occurrence of a t a r g e t t r i a l a n d t h e r o o t mean s q u a r e d (RMS) d e r i v a t i o n s f o r t h e a c c u r a c y t a s k s i n S t u d i e s 1 a n d 2.

R

Task

E

RMS ( i n %)

Word

R-H

R-L

I-H

I-L

( S t u d y 1)

5.20

4.40

3.72

3.40

2.98

.459

1.27

( S t u d y 2)

5.22

4.38

3.56

3.26

2.86

.550

1.70

( S t u d y 2)

4.87

4.29

3.84

3.85

3.42

.880

1.67

Combined D a t a

5.08

4.33

3.68

3.51

3.08

Postcue

Precue

Postcue Precue

2.54 .514 .823

t o t h i s l e v e l o f d e t a i l , w e w i l l p r o c e e d no f u r t h e r . U n l i k e t h e a c c u r a c y m o d e l w h e r e t h e f i t o f t h e model was e n l i g h t e n i n g a b o u t p r es u m ed s u b j e c t b i a s i n t h e t a s k , the qualitative f e a t u r e s o f t h e RT d a t a f o l l o w r a t h e r d i r e c t l y f r o m t h e q u a l i t a t i v e d e s c r i p t i o n o f t h i s model. The c o m p l e t i o n o f the q u a n t i f i c a t i o n o f t h i s model might prove an i n t e r e s t i n g e x e r c i s e b u t would b e u n l i k e l y t o b e e x t r e m e l y r e v e a l i n g , p a r t i c u l a r l y s i n c e t h e e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e were very small.

STUDY 2:

PRECUE VERSUS POSTCUE

W h er eas i t i s n o t p o s s i b l e t o c o m p a r e d i r e c t l y t h e m a g n i t u d e o f a c c u r a c y a n d RT e f f e c t s , t h e d i f f e r e n c e s i n a c c u r a c y betwe en words and i r r e g u l a r - l o w anagrams i n t h e

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a c c u r a c y t a s k was 2 1 % . The d i f f e r e n c e b e t w e e n t h e s e same c o n d i t i o n s i n t h e RT t a s k w a s o n l y 34 msec o r 5 .8 % o f t h e a v e r a g e RT o f 581 msec. 3 o e s t h i s r e p r e s e n t a r e a l d i f f e r e n c e i n t h e u t i l i z a t i o n o f o r t h o g r a p h i c s t r u c t u r e i n t h e two t a s k s ? the t a s k s a l l o w more o f a I f s o , wh at p r o p e r t i e s o f contribution of orthographic s t r u c t u r e i n one t a s k than i n t h e other? The o b s e r v a t i o n o f s i g n i f i c a n t a d v a n t a g e s f o r w o r d s an d pseudowords o v e r nonwords and s i n g l e l e t t e r s i n t h e p o s t c u e R e i c h e r t a s k ( B a r o n & T h u r s t o n , 1 9 7 3 ; R e i c h e r , 1969; Thompson & M a s s a r o , 1 9 7 3 ; W h e e l e r , 1 9 7 0 ) and t h e a b s e n c e o f t h e s e e f f e c t s i n p r e c u e d e t e c t i o n t a s k s ( B j o r k & Estes, 1973; E s t e s , B j o r k , & S k a a r , 1 9 7 4 ; M a s s a r o , 1 9 7 3 ; Thompson & M a s s a r o , 1 9 7 3 ) h a s l e d t o t h e s u g g e s t i o n t h a t precuing p r e c l u d e s t h e c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e . The subject in a precue t a s k p r e s u m a b l y m a t c h e s t h e f e a t u r e s o f t h e remembered t a r g e t l e t t e r d i r e c t l y t o t h e f e a t u r e s o f t h e i n c o m i ng v i s u a l d i s p l a y . This s t r a t e g y precludes using orthographic structure t o assist i n resolution of t h e display. Thus, o n e h y p o t h e s i s is t h a t precuing promotes s m a l l e r advantages f o r s t r u c t u r e d d i s p l a y s . Study 2 t e s t s whether a precue, p e r se, a c c o u n t s f o r diminished e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e . The p o s t c u e a c c u r a c y t a s k o f t h e S t u d y 1 was r e p l i c a t e d i n o n e c o n d i t i o n w h i l e a comparable precue accuracy t a s k was used i n t h e o t h e r condition. I f p r e c u i n g a l w a y s a l l o w s m a t c h e s t o b e made a t a feature detection level, then the e f f e c t s of orthographic structure should be severely attenuated i n t h e precue accuracy task. On t h e o t h e r h a n d , i f t h e d i s p l a y i n t h e a c c u r a c y t a s k i s r e s o l v e d t o t h e f u l l e s t e x t e n t p o s s i b l e an d o r t h o g r a p h i c structure contributes t o resolution, then the results for p r e c u e and p o s t c u e a c c u r a c y s h o u l d b e c o m p a r a b l e e x c e p t , perhaps, f o r d i f f e r e n t i a l memory l o a d s i n t h e two c o n d i t i o n s . The t e s t s t r i n g s , a p p a r a t u s , a n d d i s p l a y s e q u e n c e s were i d e n t i c a l t o t h o s e o f t h e a c c u r a c y e x p e r i m e n t i n S t u d y 1. One half of t h e s u b j e c t s received the precue t a s k on t h e f i r s t day and t h e p o s t c u e t a s k o n t h e s e c o n d d a y ; f o r t h e remaining s u b j e c t s t h i s o r d e r was r e v e r s e d . The p r e c u e t a s k i n v o l v e d t h e p r e s e n t a t i o n o f t h e t a r g e t l e t t e r f o r 5 0 0 msec f o l l o w e d b y t h e l e t t e r s t r i n g 1 sec l a t e r . The l e t t e r s t r i n g was p r e s e n t e d before t h e t a r g e t i n t h e postcue task. I n both t a s k s t h e l e t t e r s t r i n g was e x p o s e d f o r a s h o r t d u r a t i o n and masked t o g i v e a n a v e r a g e p erfo rman ce o f 75% c o r r e c t . Eighteen s u b j e c t s wer e t e s t e d i n t h e e x p e r i m e n t . The d e t a i l s o f t h e m e t h o d , p r o c e d u r e , a n d r e s u l t s a r e p r e s e n t e d i n A p p en d i x 4 . 2


63

Or t h o g r a p h i c S t r u c t u r e Figure 4.12 presents percentage correct target identifications a s a function of the five levels of orthographic structure. The p r e c u e t a s k v e r s u s t h e p o s t c u e A s c a n be s e e n i n t h e figure, t a s k is t h e curve parameter. l a r g e e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e were f o u n d i n b o t h t h e p r e c u e a n d p o s t c u e t a s k s , a l t h o u g h s l i g h t l y l a r g e r e f f e c t s were f o u n d i n t h e p o s t c u e t a s k . The p o s t c u e e x p e r i m e n t r e p l i c a t e s t h e previous study. The p r e c u e r e s u l t s a r e v e r y s i m i l a r t o t h e postcue r e s u l t s , although t h e a t t e n t u a t i o n of t h e orthographic s t r u c t u r e e f f e c t s i n t h e precue t a s k over t h e postcue t a s k is statistically significant. The p r i m a r y f o c u s o f t h i s e x p e r i m e n t was t o d e t e r m i n e t h e r e l a t i o n s h i p o f precue accuracy performance t o postcue accuracy

I

w n 60

-

-

Postcue Precue

50

F i g u r e 4.12

WORD

R-H

R-L

I-H

I-L

Percentage c o r r e c t a s a function of d i s p l a y type i n t h e p r e c u e a n d p o s t c u e c o n d i t i o n s o f S t u d y 2.

64

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performance. Although t h e i n t e r a c t i o n o f t a s k w i t h d i s p l a y conditions suggests a smaller i n f l u e n c e of o r t h o g r a p h i c s t r u c t u r e i n t h e precue than postcue t a s k , t h e results a r e s u f f i c i e n t t o r e j e c t t h e h y p o t h e s i s t h a t p r e c u i n g promotes a d r a s t i c r e d u c t i o n i n t h e u s e of o r t h o g r a p h i c s t r u c t u r e . The e f f e c t s o f s t r u c t u r e were v e r y s t r o n g f o r b o t h p r e c u e and p o s t c u e , and t h e d i f f e r e n c e between t h e two t a s k s was s m a l l by comparison. The o b s e r v e d i n t e r a c t i o n o f t a s k w i t h d i s p l a y c o n d i t i o n s p r o b a b l y r e f l e c t s d i f f e r e n t memory r e q u i r e m e n t s f o r t h e two I t is r e a s o n a b l e t o e x p e c t t h a t p e r f o r m a n c e m i g h t be tasks. p o o r e r i n a p o s t c u e t a s k b e c a u s e t h e n e c e s s i t y of r e t a i n i n g t h e d i s p l a y u n t i l t h e t a r g e t l e t t e r is p r o c e s s e d c o u l d l e a d t o memory l o s s . I t might f u r t h e r be expected t h a t f o r g e t t i n g would b e g r e a t e r f o r t h e more p o o r l y - s t r u c t u r e d displays ( B a d d e l e y , 1964). Any d i f f e r e n c e s i n o v e r a l l a c c u r a c y b e t w e e n t h e postcue than i n precue tasks a r e n o t meaningful because t h e a d a p t i v e a l g o r i t h m endeavored t o m a i n t a i n o v e r a l l a c c u r a c y a t 75%. I n f a c t , s u b j e c t s required s i g n i f i c a n t l y longer exposures i n t h e postcue than t h e precue task. The l o n g e r d u r a t i o n s f o r the. postcue t a s k a r e c o n s i s t e n t with t h e idea t h a t f o r g e t t i n g occurred t o a g r e a t e r degree i n t h e postcue than i n t h e precue task. Similarity Effects Figure 4.13 gives the percentage of correct i d e n t i f i c a t i o n s of t h e t a r g e t l e t t e r a s a f u n c t i o n of t h e Similar number of s i m i l a r n o n t a r g e t s i n t h e t e s t d i s p l a y . r e s u l t s were o b s e r v e d i n both the p r e c u e and p o s t c u e tasks. The o v e r a l l a c c u r a c y d i f f e r e n c e s o n t a r g e t and c a t c h t r i a l s f o r both tasks a r e discussed i n t h e next s e c t i o n . Accuracy d e c r e a s e d w i t h i n c r e a s e s i n t h e number o f s i m i l a r n o n t a r g e t s on c a t c h t r i a l s b u t remained r e l a t i v e l y c o n s t a n t on t a r g e t t r i a l s . Although t h e s i m i l a r i t y e f f e c t s a r e s m a l l e r i n magnitude, t h e c a t c h t r i a l s b u t n o t t h e t a r g e t t r i a l s r e p l i c a t e t h e r e s u l t s o f t h e a c c u r a c y t a s k i n S t u d y 1. The d e c r e a s e i n a c c u r a c y on c a t c h t r i a l s w i t h i n c r e a s e s i n t h e number o f s i m i l a r l e t t e r s a p p e a r s t o be a r e l a t i v e l y r e l i a b l e r e s u l t . In c o n t r a s t , a n y e f f e c t o f s i m i l a r n o n t a r g e t s on t a r g e t t r i a l s a p p e a r s t o be s m a l l e r i n m a g n i t u d e and l e s s r e l i a b l e .


65

Target Versus Catch T r i a l s F i g u r e 4 . 1 4 p r e s e n t s t h e p e r c e n t a g e of c o r r e c t t a r g e t i d e n t i f i c a t i o n s f o r t a r g e t and c a t c h t r i a l s i n t h e p r e c u e and postcue accuracy tasks. Replicating t h e r e s u l t s of t h e p r e v i o u s s t u d y , o v e r a l l a c c u r a c y was much g r e a t e r on c a t c h t r i a l s t han on t a r g e t t r i a l s i n t h e p o s t c u e t a s k . I n c o n t r a s t , p e r f o r m a n c e on t a r g e t t r i a l s was more a c c u r a t e t h a n on c a t c h t r i a l s i n t h e p r e c u e a c c u r a c y t a s k . The se e f f e c t s c a n be d e s c r i b e d by t h e d e c i s i o n r u l e i n t h e model. For a c c u r a c y t a s k s i t i s assumed t h a t t h e l e t t e r s t r i n g i s r e s o l v e d a s f u l l y as p o s s i b l e w i t h t h e a s s i s t a n c e of o r t h o g r a p h i c s t r u c t u r e . I f none o f t h e r e s o l v e d l e t t e r s is t h e t a r g e t , a " y e s " r e s p o n s e is a f u n c t i o n of t h e o b s e r v e r ' s a p r i o r i e x p e c t a t i o n p r o b a b i l i t y t h a t a n u n r e s o l v e d l e t t e r i s a t a r g e t and t h e number of

Precue

J l -

m L

50

0

1

2

3

NUMBER OF SIMILAR NONTARGETS

F i g u r e 4.13 '

P e r c e n t a g e c o r r e c t f o r t a r g e t and c a t c h t r i a l s i n t h e p r e c u e and p o s t c u e c o n d i t i o n s of S t u d y 2 a s a f u n c t i o n o f t h e number of s i m i l a r n o n t a r g e t l e t t e r s in the test string.

CHAPTER 4

66

unresolved l e t t e r s . I n t e r m s of t h e p r e s e n t model, the e x p e c t a t i o n p a r a m e t e r E/6 must have d i f f e r e d f o r t h e p r e c u e and postcue tasks. I n f o r m a t i o n P r o c e s s i n q Model The model was t e s t e d by f i t t i n g i t t o t h e d a t a o f t h e p r e s e n t experiment. S i x p a r a m e t e r s were e s t i m a t e d f o r e a c h s e t of 10 means: one E - v a l u e , and a s e p a r a t e R-value f o r e a c h o f t h e five display conditions, e.g. , word, r e g u l a r - h i g h , e t c . The p a r a m e t e r e s t i m a t e s and t h e i r a s s o c i a t e d root mean s q u a r e d d e v i a t i o n s a r e shown i n T a b l e 4.3 a s P o s t c u e ( S t u d y 2 ) and P r e c u e ( S t u d y 2 ) . The model p r o v i d e s a good d e s c r i p t i o n of t h e r e s u l t s of both t a s k s .

100

I

I

I

90-

y I-

8 g

I

80-

. .' --...-.-_______ p

70-

0

Obs Pre 80-

....._... Catch

...'.

.

0 % .

Target

w

CJ

I

Precue

50 100

Postcue

601

F i g u r e 4.14

I

I

I

Observed (Obs) and p r e d i c t e d (Pre) percentage c o r r e c t f o r t a r g e t and c a t c h t r i a l s f o r t h e p r e c u e and p o s t c u e c o n d i t i o n s o f S t u d y 2 a s a f u n c t i o n of d i s p l a y type.


67

Not o n l y d o e s t h e f i t of t h e model p r o v i d e s u p p o r t f o r o u r c o n c e p t u a l i z a t i o n o f t h e d e c i s i o n mechanism, b u t t h e p a r a m e t e r v a l u e s a r e meaningful. I t is i n t e r e s t i n g t o n o t e t h a t t h e a p p a r e n t b i a s toward "no" r e s p o n s e s i n t h e p o s t c u e t a s k a c t u a l l y r e f l e c t s a n a c c u r a t e and u n b i a s e d a s s e s s m e n t o f t h e e q u a l p r o b a b i l i t y o f t a r g e t and c a t c h t r i a l s . The s u b j e c t s i n t h e p r e c u e t a s k , however, d o e x h i b i t a marked b i a s t o w a r d e x p e c t i n g t h e p r e s e n c e of a t a r g e t . Smith e t a l . ( 1 9 7 6 ) have reported s i m i l a r f i n d i n g s i n a precued t a r g e t r e c o g n i t i o n task and s u g g e s t t h a t o b s e r v e r s i n p r e c u e t a s k s may e r r o n e o u s l y i n c o r p o r a t e mask f e a t u r e s i n making t h e i r j u d g m e n t s and t h u s t e n d t o see t h e t a r g e t i n t h e mask more o f t e n t h a n m i g h t b e e x p e c t e d . By m a n i p u l a t i n g t h e n a t u r e o f t h e m a s k which f o l l o w s t h e d i s p l a y t h e y found a more p r o n o u n c e d e f f e c t when t h e d i s p l a y and mask s h a r e d f e a t u r e s t h a n when t h e y d i d n o t . P e r h a p s e v e n more i n t e r e s t i n g t h a n t h e E - p a r a m e t e r s were t h e R-values which c o r r e s p o n d t o t h e number of l e t t e r s a c t u a l l y resolved f o r each d i s p l a y type. The p a r a m e t e r v a l u e s f o r R a s a f u n c t i o n of display type change s y s t e m a t i c a l l y w i t h o r t h o g r a p h i c s t r u c t u r e a c r o s s b o t h t h e p r e c u e and t h e p o s t c u e experiments. The l a r g e r e f f e c t o f d i s p l a y t y p e f o r t h e p o s t c u e t h a n f o r t h e p r e c u e t a s k i s r e f l e c t e d by t h e l a r g e r s p r e a d of t h e R-values f o r t h e p o s t c u e t a s k . A l t h o u g h t h e i n t e r a c t i o n of d i s p l a y c o n d i t i o n s w i t h t a s k i n t h e p r e s e n t e x p e r i m e n t i m p l i e s t h a t R - v a l u e s were somewhat d i f f e r e n t i n t h e p r e c u e and p o s t c u e t a s k s , a l l 2 0 d a t a p o i n t s were a l s o f i t w i t h s e v e n p a r a m e t e r s by a s s u m i n g t h a t a s i n g l e s e t o f f i v e R - v a l u e s and two E - v a l u e s , one f o r p r e c u e and one f o r t h e p o s t c u e , would b e s u f f i c i e n t . These p a r a m e t e r s and t h e i r a s s o c i a t e d r o o t mean s q u a r e d d e v i a t i o n s a r e a l s o g i v e n i n T a b l e 4 . 3 a s Combined Data. The p r e d i c t e d r e s u l t s o f t h e s e v e n - p a r a m e t e r model a r e shown a l o n g w i t h t h e o b s e r v e d r e s u l t s The r e a s o n a b l y good d e s c r i p t i o n of t h e r e s u l t i n F i g u r e 4.14. shows t h a t t h e combined f i t o f t h e two t a s k s i s q u i t e acceptable. I n a d d i t i o n , r e d u c i n g t h e number of p a r a m e t e r s from 1 2 t o 7 i n c r e a s e d t h e t o t a l r o o t mean s q u a r e d d e v i a t i o n by less t han one p e r c e n t (from 1 . 6 % t o 2 . 5 % ) .

STUDY 3 :

MIXED-CASE

The r e s u l t s o f t h e c o m p a r i s o n between p r e c u e and p o s t c u e t a s k s i n d i c a t e s t h a t precuing a l o n e is n o t a s u f f i c i e n t condition t o cause a d r a s t i c reduction i n t h e u s e of

CHAPTER

A

orthographic s t r u c t u r e , a t l e a s t i n accuracy tasks. It still m i g h t b e t h e c a s e , however, t h a t p r e c u i n g i n t h e RT t a s k i n which u n l i m i t e d v i e w i n g time i n s u r e s t h a t a l l o f t h e f e a t u r e s o f t h e d i s p l a y c a n be e x t r a c t e d p r o m o t e s a f e a t u r e d e t e c t i o n strategy. The n e x t e x p e r i m e n t a d d r e s s e s t h e i s s u e o f w h e t h e r o r n o t d i s c o u r a g i n g a f e a t u r e d e t e c t i o n s t r a t e g y w i l l promote t h e u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e i n t h e r e s o l u t i o n o f the test s t r i n g Much o f t h e i n t u i t i v e a p p e a l o f t h e f e a t u r e d e t e c t i o n s t r a t e g y is t h e i d e a t h a t r e c o g n i t i o n o f t h e t a r g e t l e t t e r c o u l d O C C U K o n t h e b a s i s o f o n l y a few f e a t u r e s and w i t h o u t t h e The n e c e s s i t y of f u l l y r e s o l v i n g a l l f e a t u r e s o f t h e l e t t e r . e f f e c t i v e n e s s o f t h i s s t r a t e g y would be r e d u c e d i f t h e s p e c i f i c v i s u a l c o n f i g u r a t i o n o f t h e t a r g e t , and t h u s t h e e x a c t form o f t h e c r i t i c a l f e a t u r e s , could n o t be p r e d i c t e d . One p r o c e d u r e would be t o h a v e t h e l e t t e r s t r i n g a p p e a r i n s e v e r a l d i f f e r e n t f o n t s w i t h t h e f o n t o f t h e t a r g e t a p p e a r i n g on a g i v e n t e s t t r i a l being unpredictable. The p r e s e n t e x p e r i m e n t a p p r o x i m a t e d t h i s method by p r e s e n t i n g t h e displays printed half i n u p p e r c a s e l e t t e r s and h a l f i n l o w e r c a s e . Thus, t h e l e t t e r c a s e of t h e t a r g e t l e t t e r was n o t c o m p l e t e l y p r e d i c t a b l e . Whereas i t m i g h t s t i l l be p o s s i b l e t o d e t e c t f e a t u r e s f o r u p p e r c a s e and lowercase l e t t e r s simultaneously, t h e e x t r a e f f o r t should reduce the effectiveness of the feature detection s t r a t e g y . T h e r e f o r e , i t is p r e d i c t e d t h a t i f t h e f e a t u r e d e t e c t i o n s t r a t e g y i s t h e cause o f t h e small e f f e c t o f orthographic structure i n a precue RT task, then a significantly larger effect should be observed i n t h e mixed-case c o n d i t i o n , where t h e e f f e c t i v e n e s s of t h e f e a t u r e d e t e c t i o n s t r a t e g y w i l l be d i m i n i s h e d . T a y l o r , M i l l e r , and J u o l a ( 1 9 7 7 ) h a v e r e p o r t e d t h a t m i x i n g c a s e s d i s r u p t s t h e u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e i n word p e r c e p t i o n . The amount o f d i s r u p t i o n was found t o b e a m o n o t o n i c a l l y i n c r e a s i n g f u n c t i o n o f t h e number of t r a n s i t i o n s between c a s e s i n t h e s t r i n g t o be p e r c e i v e d . To m i n i m i z e t h e d i s r u p t i v e i n f l u e n c e o f c a s e t r a n s i t i o n s on t h e u t i l i z a t i o n o f o r t h o g r a p h i c S t K U C t U K e , o n l y a s i n g l e t r a n s i t i o n between t h e t h i r d and f o u r t h l e t t e r s was used i n t h i s e x p e r i m e n t . The p r o c e d u r e was t h e same a s t h e e a r l i e r r e a c t i o n t i m e experiment with t h e following modifications. The t a r g e t l e t t e r was p r e s e n t e d a t t h e b e g i n n i n g o f e a c h t r i a l i n b o t h i t s u p p e r c a s e and l o w e r c a s e f o r m s . On e a c h t r i a l , t h e t e s t s t r i n g was p r e s e n t e d s o t h a t e i t h e r t h e f i r s t t h r e e l e t t e r s were i n u p p e r c a s e and t h e l a s t t h r e e l e t t e r s i n l o w e r c a s e or t h e

.


o p p o s i t e OCCUKKed. The d e t a i l s of t h e method, p r o c e d u r e , r e s u l t s a r e p r e s e n t e d i n Appendix 4.3.

69

and

Orthographic S t r u c t u r e F i g u r e 4.15 p r e s e n t s t h e mean r e a c t i o n times i n t h e t a s k a s a f u n c t i o n o f o r t h o g r a p h i c s t r u c t u r e . T h e r e was o n l y a 7 msec a d v a n t a g e of words o v e r r e g u l a r - h i g h pseudowords. The 30 msec a d v a n t a g e o f regular over irregular s t r i n g s was s i g n i f i c a n t a s was t h e 1 4 msec a d v a n t a g e of s t r i n g s h i g h i n p o s i t i o n a l f r e q u e n c y r e l a t i v e t o s t r i n g s low i n p o s i t i o n a l frequency. By m i x i n g t h e c a s e s o f t h e l e t t e r s i n t h e p r e s e n t s t u d y , t h e o v e r a l l e f f e c t of o r t h o g r a p h i c s t r u c t u r e i n c r e a s e d from 34 msec i n t h e r e a c t i o n t i m e e x p e r i m e n t o f S t u d y 1 t o 5 1 msec i n

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R e a c t i o n time and p e r c e n t a g e c o r r e c t a s a f u n c t i o n o f d i s p l a y t y p e i n S t u d y 3: Nixed-Case

70

CHAPTER 4

t h e p r e s e n t mixed-case r e a c t i o n t i m e s t u d y . Mixing t h e c a s e s I t is, i n c r e a s e d t h e o v e r a l l r e a c t i o n t i m e by a b o u t 120 msec. t h e r e f o r e , n e c e s s a r y t o a s k w h e t h e r t h e 17 msec i n c r e a s e f o r t h e e f f e c t o f o r t h o g r a p h i c s t r u c t u r e is m e a n i n g f u l . I f we can assume t h a t t h e 120 msec i n c r e a s e i n RTs t o mixed-case d i s p l a y s represents the additional visual processing required, then the 17 msec i n c r e a s e i n o r t h o g r a p h i c s t r u c t u r e e f f e c t s may p r o v i d e a meaningful e v a l u a t i o n of t h e i n f l u e n c e of o r t h o g r a p h i c s t r u c t u r e i n t h e RT t a s k . The i n c r e a s e i n t h e e f f e c t o f orthographic structure r e l a t i v e t o the additional visual is 1 4 % . Even 1 4 % , however, may b e a n processing required underestimate of t h e s i z e of t h e e f f e c t o f o r t h o g r a p h i c s t r u c t u r e s i n c e t h e a d d i t i o n a l 120 msec o f p r o c e s s i n g r e q u i r e d s t i m u l i may i n c l u d e a d d i t i o n a l t i m e needed f o r by mixed-case t h e c o m p a r i s o n p r o c e s s when t h e t a r g e t c a n o c c u r i n e i t h e r uppercase o r lowercase. Similarity Effects I f mixing t h e c a s e s a t t e n u a t e d t h e f e a t u r e d e t e c t i o n s t r a t e g y t h e n w e would e x p e c t a d e c r e a s e i n t h e e f f e c t s o f t h e number o f s i m i l a r n o n t a r g e t l e t t e r s i n t h e d i s p l a y o n c a t c h t r i a l s . The s i m i l a r i t y a n a l y s e s a r e c o m p l i c a t e d by t h e m i x t u r e o f upper- and l o w e r c a s e s i n t h e s t r i n g . Because t h e c o n f u s i o n s e t s were d e r i v e d from confusions o f lowercase l e t t e r s , a p p l i c a t i o n of these c o n f u s i o n s e t s t o t h e d a t a w i t h o u t re g a rd t o l e t t e r c a s e s would n o t be a p p r o p r i a t e . Therefore, a r e s t r i c t e d s i m i l a r i t y a n a l y s i s was d o n e by e x a m i n i n g o n l y t h e lowercase l e t t e r s i n t h e d i s p l a y s t r i n g s . When t h i s was d o n e , t h e r e were o n l y two v i a b l e s i m i l a r i t y c a t e g o r i e s : z e r o and one s i m i l a r l e t t e r s . For t a r g e t t r i a l s t h e means were 658 and 658 msec f o r t h e z e r o and one c a t e g o r i e s r e s p e c t i v e l y . For c a t c h t r i a l s t h e s e means were 7 3 1 and 756 msec. T h e s e r e s u l t s r e p l i c a t e t h e RT t a s k i n S t u d y 1; RTs f o r c a t c h t r i a l s b u t n o t t a r g e t t r i a l s i n c r e a s e w i t h t h e number o f s i m i l a r n o n t a r g e t s i n the test string. Based on t h e s i m i l a r i t y a n a l y s e s , m i x i n g t h e c a s e s d i d not appear t o a t t e n t u a t e t h e f e a t u r e d e t e c t i o n s t r a t e g y . The e x p e r i m e n t p r o v i d e s mixed e v i d e n c e f o r t h e hypothesis t h a t a f e a t u r e d e t e c t i o n s t r a t e g y o c c u r s i n precue RT t a s k s . The e f f e c t o f o r t h o g r a p h i c s t r u c t u r e was i n c r e a s e d somewhat by mixing t h e c a s e s and i t m i g h t h a v e been c o n c l u d e d t h a t u s e o f a f e a t u r e d e t e c t i o n s t r a t e g y was p r e c l u d e d and more use made o f o r t h o g r a p h i c c o n t e x t . However, t h e f a i l u r e t o a t t e n u a t e s i m i l a r i t y e f f e c t s p r e c l u d e s any firm conclusion about t h e f e a t u r e d e t e c t i o n s t r a t e g y . Either the subjects


71

p e r s i s t e d i n t h e now more d i f f i c u l t t a s k o f l o o k i n g f o r f e a t u r e m a t c h e s i n t w o - l e t t e r cases o r f e a t u r e d e t e c t i o n is n o t t h e c o r r e c t e x p l a n a t i o n f o r t h e r e s u l t s o f e i t h e r o f t h e two experiments.

STUDY 4 :

L I M I T E D V I E W I N G TIME

In another attempt t o discourage t h e f e a t u r e d e t e c t i o n s t r a t e g y , s u b j e c t s were not g i v e n u n l i m i t e d v i e w i n g t i m e i n t h e r e a c t i o n time t a s k of t h e p r e s e n t e x p e r i m e n t . I n t h e RT t a s k ( S t u d i e s 1 and 3 ) , t h e s u b j e c t s were g i v e n u n l i m i t e d time and hence a l l of t h e v i s u a l i n f o r mat i o n n e c e s s a r y f o r d e t a i l e d stimulus displays. In the perceptual r e s o l u t i o n of t h e a c c u r a c y t a s k ( S t u d i e s 1 and 2 ) , v i e w i n g time was s h o r t e n e d s o t h a t v i s u a l i n f o r m a t i o n was i n a d e q u a t e t o c l e a r l y r e s o l v e a l l of t h e d i s p l a y . D e c i s i o n s a t a f e a t u r e d e t e c t i o n l e v e l may depend on t h e c e r t a i n t y t h a t a l l t h e v i s u a l i n f o r m a t i o n w i l l be resolved. I f s o , l i m i t i n g v i e w i n g time i n t h e RT t a s k s h o u l d i n c r e a s e t h e s i z e of o r t h o g r a p h i c s t r u c t u r e e f f e c t s . S t u d y 4 t e s t e d t h i s h y p o t h e s i s by g i v i n g t h e s u b j e c t s t h e d i s p l a y f o r a However, i t was n o t p o s s i b l e t o l i m i t v i e w i n g l i m i t e d time. time a s s e v e r e l y a s i n t h e p r e v i o u s a c c u r a c y t a s k s and s t i l l maintain e r r o r r a t e s low enough to permit meaningful S t u d y 4 was a h y b r i d ; v i e w i n g time was i n t e r p r e t a t i o n of RTs. s h o r t e n e d and e r r o r r a t e s a l l o w e d t o r i s e b u t n e i t h e r was t a k e n t o extremes. The s t i m u l i and a p p a r a t u s were t h e same a s i n t h e r e a c t i o n time e x p e r i m e n t o f S t u d y 1. Rather than l e a v i n g t h e s t i m u l u s d i s p l a y on u n t i l t h e s u b j e c t r e s p o n d e d , t h e d i s p l a y was p r e s e n t e d f o r o n l y 2 0 0 msec and f o l l o w e d i m m e d i a t e l y by a masking s t i m u l u s . On t h e b a s i s of t h e p i l o t work, t h i s d u r a t i o n was c h o s e n b e c a u s e i t n o t o n l y l i m i t e d v i e w i n g time b u t a l s o gave t h e s u b j e c t s u f f i c i e n t v i s u a l information t o respond r e a s o n a b l y a c c u r a t e l y . S i x t e e n s u b j e c t s were c h o s e n from t h e same p o p u l a t i o n a s t h e e a r l i e r s t u d i e s . A l l o t h e r d e t a i l s a r e g i v e n i n Appendix 4 . 4 .

Or t h o g r a p h i c S t r u c t u r e F i g u r e 4.16 p r e s e n t s t h e r e a c t i o n time f o r c o r r e c t r e s p o n s e s as a f u n c t i o n o f o r t h o g r a p h i c s t r u c t u r e . A s c a n b e seen i n t h e f i g u r e , no e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e were observed. Although o r t h o g r a p h i c s t r u c t u r e d i d n o t have a time, it did affect significant effect on reaction

12

CHAPTER 4

a c c u r a c y . The small d i f f e r e n c e s i n a c c u r a c y a s a f u n c t i o n of orthographic structure were found to be s t a t i s t i c a l l y s i g n i f i c a n t . By l i m i t i n g t h e d i s p l a y d u r a t i o n , i t a p p e a r s t h a t t h e experiment begins t o approximate an accuracy experiment, and t h e s m a l l e r e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e c a n s i m p l y be a t t r i b u t e d t o t h e o v e r a l l high l e v e l of performance. Similarity Effects Although accu r acy v a r i e d s l i g h t l y w i t h d i f f e r e n c e s i n o r t h o g r a p h i c s t r u c t u r e , t h e r e were no s i g n i f i c a n t c h a n g e s i n a c c u r a c y a s a f u n c t i o n of t h e number o f s i m i l a r n o n t a r g e t s i n t h e t e s t d i s p l a y . I n c o n t r a s t , t h e RTs c o n t i n u e d t o r e v e a l t h e c o n s i s t e n t f i n d i n g t h a t RTs on c a t c h t r i a l s i n c r e a s e d w i t h i n c r e a s e s i n t h e number of s i m i l a r n o n t a r g e t s w he re a s RTs on t a r g e t t r i a l s showed no e f f e c t . A c c o r d i n g l y , t h e r e s u l t s show

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R e a c t i o n t i m e and p e r c e n t a g e c o r r e c t a s a f u n c t i o n of d i s p l a y t y p e i n S t u d y 4 : L i m i t e d Viewing Time.


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t h a t a n o r t h o g r a p h i c s t r u c t u r e e f f e c t i n terms of r e s p o n s e a c c u r a c y c a n c o e x i s t w i t h a s i m i l a r i t y e f f e c t on RT. This r e s u l t r e v e a l s t h a t a f e a t u r a l d e t e c t i o n s t r a t e g y a s i n d e x e d by s i g n i f i c a n t s i m i l a r i t y e f f e c t s does not preclude a s i g n i f i c a n t It appears t h a t c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e . o r t h o g r a p h i c s t r u c t u r e e f f e c t s c a n be found i n b o t h a c c u r a c y and RT m e a s u r e s , b u t t h a t RT e f f e c t s a r e n o t a s r e l i a b l e o r s e n s i t i v e a s accuracy e f f e c t s . Target Versus Catch T r i a l s ( 5 6 3 msec) w e r e r e s p o n d e d t o more q u i c k l y Target t r i a l s t h a n c a t c h t r i a l s ( 6 3 5 msec) w h e r e a s t h e r e was no s i g n i f i c a n t d i f f e r e n c e between t h e two k i n d s o f t r i a l s i n t e r m s o f r e s p o n s e accuracy.

Discussion The r e s u l t s d i s c o n f i r m t h e hypothesis t h a t limiting v i e w i n g time m i g h t i n c r e a s e t h e i n f l u e n c e of o r t h o g r a p h i c s t r u c t u r e on RT. R e a c t i o n times were found t o be u n i f o r m o v e r conditions. However, t h e p a t t e r n o f e r r o r r a t e s r e f l e c t e d t h e i n f l u e n c e of s t r u c t u r e . Limiting v i s u a l information c l e a r l y h a s a n i n f l u e n c e on a c c u r a c y , and t h i s i n f l u e n c e is m o d u l a t e d structure. A s for the by t h e p r e s e n c e of orthographic u n u s u a l l y u n i f o r m RTs, t h e y m i g h t r e f l e c t t h e s u b j e c t s h a v i n g established and maintained a self-imposed response d e a d l i n e . T h e r e f o r e , any e f f e c t o f o r t h o g r a p h i c s t r u c t u r e would be r e f l e c t e d o n l y o n p e r f o r m a n c e a c c u r a c y .

STUDY 5 :

SPEEDED RT TASK WITH GOOD VISUAL INFORMATION

S t u d y 5 t e s t s between two h y p o t h e s e s o f t h e d i f f e r e n c e s i n t h e s e n s i t i v i t y o f t h e a c c u r a c y and RT t a s k s t o o r t h o g r a p h i c s t r u c t u r e . According t o t h e f i r s t h y p o t h e s i s , t h e d i f f e r e n c e between t h e a c c u r a c y and RT t a s k s c o u l d be d u e t o a t r a d e - o f f between t h e contribution of stimulus information and o r t h o g r a p h i c s t r u c t u r e i n t h e t a s k . T h e r e is a b u n d a n t s t i m u l u s i n f o r m a t i o n i n t h e RT t a s k , and t h e r e f o r e , t h e r e may be v e r y l i t t l e o p p o r t u n i t y f o r knowledge a b o u t o r t h o g r a p h i c s t r u c t u r e I n t h e a c c u r a c y t a s k , on t h e t o c o n t r i b u t e t o performance. o t h e r hand, t h e s t i m u l u s information i s i n a d e q u a t e and consequently, there is considerable opportunity for

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CHAPTER 4

o r t h o g r a p h i c knowledge t o e x e r t a n i n f l u e n c e . This explanation i s c l e a r l y d i f f e r e n t from t h e f e a t u r e d e t e c t i o n s t r a t e g y a feature detection discussed e a r l i e r . In the case of s t r a t e g y , t h e r e is an o p p o r t u n i t y f o r orthographic s t r u c t u r e t o e x e r t an i n f l u e n c e b u t a d e c i s i o n ab o ut t h e l e t t e r s t r i n g is made w i t h o u t u t i l i z i n g t h e s t r u c t u r e . By c o n t r a s t , i n t h e c a s e of a t r a d e - o f f between v i s u a l i n f o r m a t i o n and o r t h o g r a p h i c s t r u c t u r e , t h e complete visual information precludes a c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e . Evidence f o r t h e t r a d e - o f f between t h e c o n t r i b u t i o n s of s t i m u l u s i n f o r m a t i o n and knowledge comes from a number o f RT e x p e r i m e n t s t h a t have i n d e p e n d e n t l y v a r i e d s t i m u l u s q u a l i t y and knowledge ( c . f . , Meyer, S c h v a n e v e l d t , & Ruddy, 1 9 7 5 ) . M a S S a K O , J o n e s , Lipscomb, and S c h o l z ( 1 9 7 8 ) , f o r e x a m p l e , had s u b j e c t s name a word a s q u i c k l y a s p o s s i b l e . The word was e i t h e r p r e s e n t e d u p r i g h t or was r o t a t e d 1 8 0 d e g r e e s i n t h e p i c t u r e p l a n e . The word was p r e c e d e d by a word " b l a n k " or by a c a t e g o r y p r i m e , which was t h e s u p e r o r d i n a t e c a t e g o r y name o f t h e t e s t word. P r i m i n g w i t h t h e c a t e g o r y name i s t h e a d v a n c e knowledge i n t h e t a s k and i t m i g h t b e e x p e c t e d t o f a c i l i t a t e p r o c e s s i n g o f t h e t e s t word. T h e r e f o r e , R T s s h o u l d b e f a s t e r on primed t h a n unprimed t r i a l s . Of c o u r s e , r o t a t i n g t h e t e s t words s h o u l d slow down t h e naming r e s p o n s e s i n c e t h e s t i m u l u s i n f o r m a t i o n i s d e g r a d e d ; we a r e n o t used t o s e e i n g and r e a d i n g rotated text. The r e s u l t s showed that priming had a n o n s i g n i f i c a n t 7 msec f a c i l i t a t i o n when t h e words were p r e s e n t e d u p r i g h t b u t a s i g n i f i c a n t 1 2 1 msec e f f e c t when words were r o t a t e d 1 8 0 d e g r e e s . S i m i l a r r e s u l t s were f o u n d i n a lexical decision task. With a good q u a l i t y t e s t d i s p l a y , p r i m i n g had e s s e n t i a l l y no e f f e c t : g i v e n a poor q u a l i t y d i s p l a y , a d v a n c e knowledge f a c i l i t a t e d p e r f o r m a n c e . In the p r e s e n t e x p e r i m e n t s , g i v e n a good q u a l i t y d i s p l a y i n t h e RT t a s k , o r t h o g r a p h i c s t r u c t u r e had a small e f f e c t ; w i t h a poor q u a l i t y d i s p l a y i n t h e accuracy t a s k , orthographic s t r u c t u r e had a l a r g e e f f e c t . that t h e c o n t r i b u t i o n of The s e c o n d h y p o t h e s i s is o r t h o g r a p h i c s t r u c t u r e i s s i m i l a r i n t h e a c c u r a c y and RT t a s k s b u t t h e a c c u r a c y t a s k a l l o w s a more d i r e c t m e a s u r e o f t h e s i z e of t h i s c o n t r i b u t i o n . I n t h e RT t a s k where t h e v i s u a l d i s p l a y i s c l e a r l y v i s i b l e and v i e w i n g time u n l i m i t e d , t h e l e t t e r s t r i n g is r e s o l v e d v e r y q u i c k l y and t h e time t o r e s o l v e t h e l e t t e r s may be s m a l l r e l a t i v e t o t h e times f o r t h e r e m a i n i n g processes of s e a r c h , comparison, d e c i s i o n , and r e s p o n s e s e l e c t i o n . Thus, t h e f a c i l i t a t i n g e f f e c t of orthographic s t r u c t u r e m i g h t be l a r g e i n terms o f t h e time s a v i n g s f o r


75

v i s u a l r e s o l u t i o n , b u t s m a l l r e l a t i v e t o t h e o v e r a l l RT. For e x a m p l e , a 20 msec e f f e c t o f s t r u c t u r e when v i s u a l r e s o l u t i o n t a k e s 100 msec w i t h o u t any c o n t r i b u t i o n o f s t r u c t u r e would expand a 500 msec RT by o n l y 4 % . Even though t h i s 20% e f f e c t on v i s u a l r e s o l u t i o n is i m p o r t a n t , i t would a p p e a r s m a l l RT. By contrast, the visual relative t o the overall i n f o r m a t i o n i n t h e a c c u r a c y t a s k i s l i m i t e d and e r r o r s a r e a d i r e c t consequence of limitations in visual resolution. Accordingly, a f a c i l i t a t i o n of v i s u a l r e s o l u t i o n w i l l be more directly reflected in an improvement in task acc u r a c y . According t o t h i s h y p o t h e s i s , even though o r t h o g r a p h i c s t r u c t u r e c o n t r i b u t e s r o u g h l y t h e same a d d i t i o n a l i n f o r m a t i o n i n b o t h t h e RT and a c c u r a c y t a s k s , t h e s i z e o f RT e f f e c t w i l l appear small r e l a t i v e t o t h e accuracy e f f e c t . t h e s e two h y p o t h e s e s , a n I n o r d e r t o t e s t between e x p e r i m e n t was c a r r i e d o u t i n which t h e r e a d e r would h a v e good q u a l i t y v i s u a l i n f o r m a t i o n b u t a c c u r a c y r a t h e r t h a n RT would be t h e primary dependent v a r i a b l e . ~f t h e c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e is i n v e r s e l y r e l a t e d t o t h e q u a l i t y o f t h e v i s u a l information as predicted by the trade-off hypothesis, t h e n a v e r y s m a l l e f f e c t of s t r u c t u r e s h o u l d be a p p a r e n t o n a c c u r a c y . However, if the c o n t r i b u t i o n of the q u a l i t y of t h e v i s u a l s t r u c t u r e i s i n d e p e n d e n t of i n f o r m a t i o n and a c c u r a c y i s s i m p l y a more d i r e c t m e a s u r e , t h e n t h e t y p i c a l l a r g e e f f e c t s o f s t r u c t u r e on a c c u r a c y s h o u l d be o b s e r v e d . Given t h a t a c c u r a c y i s now t i e d t o 75% c o r r e c t , it s h o u l d be a more d i r e c t i n d e x of t h e c o n t r i b u t i o n o f s t r u c t u r e . T h e r e f o r e , t h e p r e s e n t e x p e r i m e n t p r o v i d e s a t e s t between t h e two h y p o t h e s e s w i t h o u t h a v i n g t o compare a c c u r a c y e f f e c t s t o RT e f f e c t s . A m o d i f i c a t i o n of a speed-accuracy t r a d e - o f f paradigm which r e q u i r e s a s p e e d e d r e a c t i o n i n s y n c h r o n i z a t i o n w i t h a s i g n a l e v e n t ( R e e d , 1 9 7 3 ) was used t o keep a v e r a g e p e r f o r m a n c e a t 75% c o r r e c t . The s u b j e c t s were g i v e n t h e t a r g e t l e t t e r f o l l o w e d by t h e d i s p l a y and w e r e r e q u i r e d t o r e s p o n d a s n e a r l y i n s y n c h r o n y w i t h t h e o f f s e t of t h e d i s p l a y a s p o s s i b l e . Using a n a d a p t i v e a l g o r i t h m , a d i s p l a y d u r a t i o n was c a l c u l a t e d t o keep t h e s u b j e c t ' s o v e r a l l a c c u r a c y a t 7 5 % . B e c a u s e t h e d u r a t i o n of t h e d i s p l a y a v e r a g e d a r o u n d 500 msec, i t seems S a f e h a v e good q u a l i t y s t i m u l u s t o assume t h a t t h e s u b j e c t s information. T h e r e f o r e , t h e t r a d e - o f f h y p o t h e s i s p r e d i c t s no e f f e c t of s t r u c t u r e whereas t h e h y p o t h e s i s t h a t a c c u r a c y i s a more d i r e c t m e a s u r e t h a n RT p r e d i c t s a l a r g e e f f e c t O f

structure.

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Procedure E l e v e n s t u d e n t s , s e l e c t e d from t h e same p o p u l a t i o n a s t h o s e i n t h e e a r l i e r e x p e r i m e n t s , were t e s t e d o n a s i n g l e d a y . A t a r g e t l e t t e r was p r e s e n t e d f o r 5 0 0 msec and f o l l o w e d by t h e t e s t d i s p l a y a f t e r a n i n t e r v a l o f 2 5 0 msec. The t e s t d i s p l a y d u r a t i o n was m o d i f i e d e v e r y 2 0 t r i a l s t h r o u g h o u t t h e e x p e r i m e n t S u b j e c t s were t o k e e p o v e r a l l p e r f o r m a n c e a t 75% c o r r e c t . i n s t r u c t e d t o respond as c l o s e t o t h e s t i m u l u s o f f s e t as p o s s i b l e and t h e y were g i v e n f e e d b a c k on t h i s t a s k a f t e r e a c h block of 20 t r i a l s . E s s e n t i a l l y , s u b j e c t s simply l e a r n e d t o m a i n t a i n a p a r t i c u l a r r e s p o n s e time, n o t t o r e s p o n d t o t h e o f f s e t of t h e d i s p l a y i t s e l f . None o f t h e s u b j e c t s had a n y d i f f i c u l t y w i t h t h i s t a s k . D e t a i l s o f t h e method, p r o c e d u r e , and r e s u l t s a r e g i v e n i n Appendix 4.5.

550

-

500

-

450

-

kB0lh

0 Catch

8 0 F i g u r e 4.17

~

70

WORD

R-H

R-L

I-H

I-L

R e a c t i o n time and p e r c e n t a g e c o r r e c t a s a f u n c t i o n o f d i s p l a y t y p e i n S t u d y 5: Speeded RT Task w i t h Good V i s u a l I n f o r m a t i o n .


77

Orthographic S t r u c t u r e F i g u r e 4.17 p r e s e n t s t h e c o r r e c t r e a c t i o n times and response accuracy a s a f u n c t i o n of o r t h o g r a p h i c s t r u c t u r e ; t a r g e t and c a t c h t r i a l s a r e p l o t t e d s e p a r a t e l y . T h e r e was a 1 5 msec e f f e c t o f o r t h o g r a p h i c s t r u c t u r e o n c o r r e c t r e a c t i o n times and a 1 . 9 % e f f e c t o n a c c u r a c y . T h e r e f o r e , no s t r o n g e f f e c t o f orthographic s t r u c t u r e on either RT or a c c u r a c y was consistent with the trade-off present. T h i s r e s u l t is h y p o t h e s i s whereby t h e c o n t r i b u t i o n o f o r t h o g r a p h i c s t r u c t u r e is i n v e r s e l y r e l a t e d t o t h e q u a l i t y of t h e v i s u a l i n f o r m a t i o n in the test string.

STUDY 6:

SPEEDED RT TASK WITH POOR VISUAL INFORMATION

The s p e e d e d RT t a s k i n S t u d y 5 p r o v i d e d e v i d e n c e t h a t t h e a c c u r a c y t a s k may g i v e l a r g e r e f f e c t s t h a n d o e s t h e RT t a s k because of t h e p o o r er q u a l i t y o f t h e v i s u a l i n f o r m a t i o n i n t h e a c c u r a c y t a s k . A c c o r d i n g l y , g i v i n g good q u a l i t y i n f o r m a t i o n i n t h e s p e e d e d RT t a s k shows no e f f e c t o f o r t h o g r a p h i c s t r u c t u r e on r e s p o n s e a c c u r a c y . B e f o r e a c c e p t i n g t h i s c o n c l u s i o n , i t i s i m p o r t a n t t o v e r i f y whether t h e speed-accuracy paradigm t h a t It was u s e d i s i t s e l f s e n s i t i v e t o o r t h o g r a p h i c s t r u c t u r e . c o u l d be t h e c a s e t h a t t h e p e r c e p t u a l s t a g e g o e s t o c o m p l e t i o n i n a l l c o n d i t i o n s and t h a t e r r o r s a r e s i m p l y a f u n c t i o n o f l a t e r s t a g e s s u c h a s r e s p o n s e s e l e c t i o n . Any small d i f f e r e n c e s i n c o m p l e t i o n times o f t h e p e r c e p t u a l s t a g e a s a f u n c t i o n o f o r t h o g r a p h i c s t r u c t u r e may n o t s i g n i f i c a n t l y i n f l u e n c e t h e a c c u r a c y o f l a t e r s t a g e s o f p r o c e s s i n g , and t h e r e f o r e , t h e d i f f e r e n c e s i n t h e p e r c e p t u a l s t a g e would n o t be r e f l e c t e d in To t e s t t h e e i t h e r response accuracy o r reaction t i m e . s s n s i t i v i t y o f t h e speeded RT t a s k , i t is n e c e s s a r y t o r e p l i c a t e t h e t a s k w i t h poor q u a l i t y i n f o r m a t i o n . I f the task i s s e n s i t i v e and t h e e f f e c t o f s t r u c t u r e is i n v e r s e l y r e l a t e d t o s t i m u l u s q u a l i t y , t h e n s i g n i f i c a n t e f f e c t s s h o u l d be found. I f t h e t a s k i s i n s e n s i t i v e t o t h e p e r c e p t u a l s t a g e , however, n o e f f e c t o f o r t h o g r a p h i c s t r u c t u r e s h o u l d be o b s e r v e d . A s d i s c u s s e d p r e v i o u s l y , MaSSaL-0 e t a l . ( 1 9 7 8 ) d e g r a d e d t h e q u a l i t y o f t e s t s t r i n g s by r o t a t i n g them 1 8 0 d e g r e e s i n t h e p i c t u r e plane. F o l l o w i n g t h i s a p p r o a c h , t h e s p e e d e d RT t a s k was r e p l i c a t e d w i t h t h e t e s t s t r i n g s r o t a t e d i n t h e same manner. Given t h a t r o t a t i o n l o w e r s t h e q u a l i t y o f t h e v i s u a l

CHAPTER 4

78

i n f o r m a t i o n , a n e f f e c t o f o r t h o g r a p h i c s t r u c t u r e s h o u l d be o b s e r v e d i f t h e s p e e d e d RT t a s k i s s e n s i t i v e t o p e r c e p t u a l d i f f e r e n c e s due t o t h e o r t h o g r a p h i c s t r u c t u r e . I f t h e task itself i s i n s e n s i t i v e t h e n no e f f e c t s o f s t r u c t u r e s h o u l d be observed. Procedure The s p e e d e d RT t a s k i n S t u d y 5 was r e p l i c a t e d e x a c t l y w i t h a new g r o u p o f s t u d e n t s e x c e p t t h a t t h e t e s t s t r i n g s were r o t a t e d 18B d e g r e e s i n t h e p i c t u r e p l a n e r a t h e r t h a n p r e s e n t e d upright. The t a r g e t l e t t e r was s t i l l p r e s e n t e d u p r i g h t . The d e t a i l s o f t h e method, p r o c e d u r e , and r e s u l t s a r e p r e s e n t e d i n Appendix 4.6.

-

Or t h o g r a p h i c S t r u c t u r e

F i g u r e 4.18 p r e s e n t s t h e c o r r e c t r e a c t i o n times and accuracy performance. T h e r e was a 7 msec e f f e c t o f s t r u c t u r e 700

Catch *------*Target

650

a\.\.

-.-./-

-m

,-”

---

600

550

-

0 Catch

O m 8 WORD F i g u r e 4.18

R-H

R-L

I-H

I-L

R e a c t i o n time and p e r c e n t a g e c o r r e c t a s a f u n c t i o n Speeded RT Task w i t h of d i s p l a y type i n Study 6: Poor V i s u a l I n f o r m a t i o n .


79

on c o r r e c t r e a c t i o n times and a 1 . 7 % e f f e c t on r e s p o n s e a c c u r a c y . The r e s u l t s o f t h i s experiment are a direct r e p l i c a t i o n o f t h o s e i n t h e p r e v i o u s s p e e d e d RT t a s k and t h e r e f o r e provide s t r o n g evidence f o r t h e idea t h a t t h e speeded RT t a s k is i n s e n s i t i v e t o p e r c e p t u a l d i f f e r e n c e s due t o t h e orthographic structure. B e f o r e t h i s c o n c l u s i o n is a c c e p t e d , i t w i l l be n e c e s s a r y t o v e r i f y t h a t o r t h o g r a p h i c however, s t r u c t u r e e f f e c t s do occur with r o t a t e d t e s t s t r i n g s i n o t h e r tasks. I n o r d e r t o have a d i r e c t l y a n a l o g o u s s i t u a t i o n t o t h e s p e e d e d RT t a s k s , t h e t a s k m u s t keep t h e t e s t s t r i n g i n v i e w during the processing period. Therefore, high accuracy is t o be e x p e c t e d and RT m u s t be t h e d e p e n d e n t m e a s u r e .

STUDY 7 :

HIGH-ACCURACY

RT TASK WITH POOR VISUAL INFORMATION

Procedure To v e r i f y t h a t o r t h o g r a p h i c s t r u c t u r e e f f e c t s d o o c c u r with rotated t e s t s t r i n g s , t h e high-accuracy reaction t i m e e x p e r i m e n t o f S t u d i e s 1 and 3 was r e p l i c a t e d b u t u s i n g r o t a t e d An u p r i g h t t a r g e t l e t t e r was r a t h e r than upright test s t r i n g s . p r e s e n t e d f o l l o w e d by a r o t a t e d t e s t s t r i n g which remained in view u n t i l t h e l a s t o f up t o f o u r s u b j e c t s r e s p o n d e d . Subjects performed a s q u i c k l y a s p o s s i b l e while maintaining high a c c u r a c y . The d e t a i l s o f t h e method, p r o c e d u r e , and r e s u l t s a r e p r e s e n t e d i n Appendix 4 . 7 . Orthographic S t r u c t u r e R e a c t i o n t i m e s g e n e r a l l y i n c r e a s e d from words t o t h e irregular-low strings. F i g u r e 4.19 shows t h a t o v e r a l l e f f e c t was 3 2 msec, which i s h i g h l y s i m i l a r t o t h e e f f e c t s o f s t r u c t u r e on n o r m a l l y p r e s e n t e d s t r i n g s ( c f . F i g u r e 4 . 9 ) . This r e s u l t shows t h a t s t r u c t u r e e f f e c t s d o o c c u r w i t h r o t a t e d s t i m u l i but t h a t they a r e not larger than the s t r u c t u r e e f f e c t s o b s e r v e d w i t h u p r i g h t s t i m u l i . The i d e a t h a t a t r a d e - o f f e x i s t s between s t i m u l u s q u a l i t y and o r t h o g r a p h i c s t r u c t u r e is n o t s u p p o r t e d by t h e s e r e s u l t s . I t appears t h a t both accuracy RT t a s k s c a n r e v e a l o r t h o g r a p h i c t a s k s and h i g h - a c c u r a c y s t r u c t u r e e f f e c t s b u t t h a t t h e s p e e d e d RT t a s k d o e s n o t .

CHAPTER 4

80

SUMMARY OF ACCURACY AND REACTION TIME EXPERIMENTS

These exper i men t s t en d t o s u p p o r t t h e i d e a t h a t p e r c e p t u a l r e s o l u t i o n of a l e t t e r s t r i n g i s f a c i l i t a t e d t o t h e d e g r e e t h e letters i n the s t r i n g a r e well-structured. Both a c c u r a c y t a s k s w i t h l i m i t e d s t i m u l u s i n f o r m a t i o n and h i g h a c c u r a c y RT t a s k s w i t h c o m p l e t e s t i m u l u s i n f o r m a t i o n a p p e a r t o be s e n s i t i v e t o t h e e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e . However, t h e m a g n i t u d e of t h e RT e f f e c t a p p e a r s s m a l l e r b e c a u s e of t h e r e l a t i v e l y l a r g e o v e r a l l RT d u e t o t h e p r o c e s s i n g time r e q u i r e d f o r o t h e r t h a n v i s u a l p r o c e s s i n g s t a g e s i n t h e RT t a s k . In contrast, a v e r a g e p e r f o r m a n c e i n t h e a c c u r a c y t a s k i s t i t r a t e d t o re m a in a t 7 5 % c o r r e c t and t h i s p e r c e n t a g e meas ure is i n f l u e n c e d a l m o s t c o m p l e t e l y by t h e v i s u a l p r o c e s s i n g s t a g e s . The p o s t h o c e v a l u a t i o n of v a r i o u s measures of o r t h o g r a p h i c s t r u c t u r e i n

E-I

H

F i g u r e 4.19

R e a c t i o n time and p e r c e n t a g e c o r r e c t a s a f u n c t i o n o f d i s p l a y t y p e i n S t u d y 7 : H igh-a c c ura c y RT Task w i t h Poor V i s u a l I n f o r m a t i o n .


81

Chapter 5 w i l l allow a more d i r e c t assessment of t h e s e n s i t i v i t y o f p e r f o r m a n c e i n t h e RT and a c c u r a c y t a s k s . A second i m p o r t a n t c o n t r i b u t i o n t o p e r f o r m a n c e is t h e featural information contained in the visual display. P e r f o r m a n c e i n b o t h t h e a c c u r a c y and RT t a s k is s e n s i t i v e t o t h e v i s u a l s i m i l a r i t y of t h e test letters t o t h e t a r g e t l e t t e r . P e r f o r m a n c e on c a t c h t r i a l s is d i s r u p t e d t o t h e e x t e n t t h a t t h e test d i s p l a y contains nontarget l e t t e r s t h a t are s i m i l a r t o t h e target letter. P er f o r man ce on target trials is n o t significantly affected since processing is primarily a function o f t a r g e t l e t t e r p r o c e s s i n g time. However, t h e r e was some h i n t t h a t s i m i l a r n o n t a r g e t s may b e i n c o r r e c t l y c o n f u s e d f o r t h e t a r g e t on t a r g e t t r i a l s an d , t h e r e f o r e , l e a d t o a c o r r e c t r e s p o n s e e v e n t h o u g h t h e t a r g e t i t s e l f was n o t r e c o g n i z e d on that t r i a l I n c o n c l u s i o n , b o t h t h e a c c u r a c y and h i g h a c c u r a c y RT t a s k s a p p e a r t o o f f e r good m e a s u r e s o f t h e u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e i n v i s u a l p r o c e s s i n g . The s p e e d e d RT t a s k does n o t r e v e a l e f f e c t s of o r t h o g r a p h i c s t r u c t u r e . Be fo re evaluating s p e c i f i c d e s c r i p t i o n s of orthographic s t r u c t u r e , some r a t i n g e x p e r i m e n t s were c a r r i e d o u t t o a s s e s s t o w ha t e x t e n t knowledge of o r t h o g r a p h i c s t r u c t u r e is c o n s c i o u s l y a v a i l a b l e and c a n b e r e p o r t e d .

.

OVERT JUDGMENTS Whereas t h e a c c u r a c y and RT e x p e r i m e n t s imply t h a t v i s u a l r e c o g n i t i o n i s s e n s i t i v e t o t h e p r e s e n c e of o r t h o g r a p h i c s t r u c t u r e , i t i s a l s o of i n t e r e s t t o d e t e r m i n e t o what e x t e n t s u b j e c t s a r e awar e o f t h i s knowledge. For t h i s p u r p o s e , s e v e r a l o v e r t judgment e x p e r i m e n t s were c o n d u c t e d . The same 2 0 0 s t i m u l u s items i n Appendix 4 . 1 B we re p r e s e n t e d t o n a t i v e E n g l i s h s p e a k i n g c o l l e g e s t u d e n t s and judgm e nts i n t h e form of r a t i n g s and p a i r e d j u d g men t s were o b t a i n e d . Answers t o t h e f o l l o w i n g q u e s t i o n s were s o u g h t . Could t h e r a t e r s r e l i a b l y a s s i g n r a t i n g s o f o r t h o g r a p h i c s t r u c t u r e t o t h e i t e m s ? Would t h e d i m e n s i o n s u t i l i z e d by t h e r a t e r s d i s c r i m i n a t e t h e items a l o n g o u r r e g u l a r i t y d i m e n s i o n , by p o s i t i o n a l f r e q u e n c y , or b o t h ? Would t h e r a t i n g s a s s i g n e d t o t h e items show a n y meaningful r e l a t i o n s h i p t o t h e i r p e r c e p t u a l a c c u r a c y and r e a c t i o n time r e s u l t s f o u n d i n t h e p r e v i o u s e x p e r i m e n t s ?

82

STUDY 8:

CHAPTER 4

T Y P I C A L I T Y RATINGS

T h r e e s e t s o f r a t i n g s were o b t a i n e d . I n t h e f i r s t one o n l y t h e 160 m e a n i n g l e s s anagrams were r a t e d . In t h e second, t h e words were t r a n s f o r m e d i n t o t h e most r e g u l a r pseudowords p o s s i b l e by t h e s u b s t i t u t i o n of a s i n g l e l e t t e r and t h e s e pseudowords were r a t e d a l o n g w i t h t h e anagrams. In the third, the words themselves were included along with the anagrams. T h e s e t h r e e p r o c e d u r e s w e r e used t o o b t a i n t h e m o s t r e l i a b l e r a t i n g s p o s s i b l e and t o d e t e r m i n e how a l t e r a t i o n s i n t h e t o t a l s e t of items r a t e d a f f e c t e d t h e r a t i n g s o f t h e All three ratings were o b t a i n e d u n d e r n e a r l y anagrams. i d e n t i c a l i n s t r u c t i o n s which a s k e d t h e r a t e r s t o b a s e t h e i r j u d g m e n t s on t h e s i m i l a r i t y o f t h e items t o E n g l i s h words where was defined as typicality of English similarity s p e l l i n g . Beyond t h e s e g e n e r a l i n s t r u c t i o n s , no s p e c i f i c a t t e m p t s were made t o i l l u s t r a t e e i t h e r s p e c i f i c r e g u l a r i t y rules or positional-frequency constraints. S u b j e c t s were a s k e d t o r a t e how much t h e l e t t e r s t r i n g s The r a t i n g s c a l e went from "most l i k e l o o k l i k e E n g l i s h words. E n g l i s h " t o " l e a s t l i k e E n g l i s h " on a s c a l e from 1 0 t o 1. C o l l e g e s t u d e n t s r a t e d t h e items in one o f t h r e e c o n d i t i o n s . Seventy subjects rated only the 160 anagrams. S i x t y - f i v e s u b j e c t s r a t e d t h e 160 anagrams p l u s 40 pseudowords which were d e r i v e d by m i s s p e l l i n g one l e t t e r i n e a c h o f t h e 40 word s t i m u l i . S i x t y - t h r e e s u b j e c t s r a t e d t h e 160 anagrams and t h e 40 words. S u b j e c t s were u r g e d n o t t o a d o p t s t r a t e g i e s o f t r y i n g t o see t h e items a s s i m i l a r t o s p e c i f i c words. Those s u b j e c t s t h a t r e c e i v e d a c t u a l words were t o l d t o d i s r e g a r d t h e s e m a n t i c c o n t e n t o f t h e words and s i m p l y j u d g e them on t h e b a s i s o f t h e i r s i m i l a r i t y t o E n g l i s h s p e l l i n g . The method, p r o c e d u r e , and d e t a i l e d r e s u l t s a r e p r e s e n t e d i n Appendix 4.8. F i g u r e 4.20 shows t h e a v e r a g e r a t i n g s f o r t h e items f o r each of t h e t h r e e g r o u p s of s u b j e c t s . The r a t i n g s a s s i g n e d t o t h e 160 anagrams were v e r y s t a b l e a c r o s s t h e t h r e e r a t i n g contexts. The s i x c o r r e l a t i o n s between a l l p o s s i b l e p a i r s o f r a t i n g s a c r o s s t h e t h r e e c o n t e x t s were a l l .97. T h i s r e s u l t demonstrates t h a t t h e r a t i n g s of t h e anagrams w e r e n o t i n f l u e n c e d by t h e p r e s e n c e o f a c t u a l words i n t h e s a m p l e o f items t o be r a t e d . The f i g u r e a l s o shows t h a t t h e r a t i n g s were p r i m a r i l y d e t e r m i n e d by t h e r e g u l a r i t y o f t h e items r a t h e r t h a n by p o s i t i o n a l f r e q u e n c y . Although t h e e f f e c t of p o s i t i o n a l f r e q u e n c y was s t a t i s t i c a l l y s i g n i f i c a n t , t h e r e s u l t s show t h a t


83

r e g u l a r i t y produced a b o u t seven times the effect that p o s i t i o n a l frequency did. The r e s u l t s i n d i c a t e t h a t when s u b j e c t s a r e a s k e d t o r a t e items on t h e b a s i s o f t h e s i m i l a r i t y t o E n g l i s h s p e l l i n g , t h e y t e n d t o e v a l u a t e t h e items i n terms o f n o t i o n s o f r e g u l a r i t y r a t h e r t h a n i n t e r m s o f t h e p o s i t i o n a l f r e q u e n c y o f t h e items. As c a n b e s e e n i n t h e f i g u r e , t h e words were r a t e d a s more t y p i c a l t h a n even the regular-high anagrams. Even t h e pseudowords c r e a t e d by m i s s p e l l i n g t h e words by a s i n g l e l e t t e r p r o d u c e d h i g h e r r a t i n g s t h a n t h e r e g u l a r anagrams. This r e s u l t means t h a t t h e word s t i m u l i and t h e i r m i s s p e l l i n g s w e r e e i t h e r more t y p i c a l a c c o r d i n g t o t h e s u b j e c t ' s n o t i o n of E n g l i s h s p e l l i n g or t h a t t h e l e x i c a l c o n t e n t o f t h e words and p o s s i b l y t h e i r m i s s p e l l i n g s c o u l d n o t be i g n o r e d i n making t h e j u d g m e n t . If t h e r a t i n g s and t h e t a r g e t s e a r c h e x p e r i m e n t s a r e m e a s u r i n g t h e same knowledge o f o r t h o g r a p h i c s t r u c t u r e , t h e n a

WORD

Figure 4.20

R-H

R-L

I-H

I-L

R a t i n g s from 1 0 ( m o s t l i k e E n g l i s h ) t o 1 ( l e a s t l i k e E n g l i s h ) a s a f u n c t i o n of d i s p l a y t y p e i n Study 8: T y p i c a l i t y Ratings.

84

CHAPTER 4

c l o s e r e l a t i o n s h i p between t h e r a t i n g s and t h e RT and a c c u r a c y m e a su r e s of the previous experiments should be o b s e r v e d . A c c o r d i n g l y , we examined t h e r e l a t i o n s h i p between t h e s e r a t i n g s and t h e p e r c e p t u a l p e r f o r m a n c e d a t a c o l l e c t e d i n S t u d i e s 1, 2 , and 3. Average RTs were o b t a i n e d f o r e a c h o f t h e 280 s t i m u l u s i t e m s by a v e r a g i n g t h e c o r r e c t r e s p o n s e RTs f o r t a r g e t and c a t c h t r i a l s from t h e r e a c t i o n time e x p e r i m e n t of S t u d y 1 and t h e mixed-case e x p e r i m e n t o f S t u d y 3. T h i s p r o v i d e d a n a v e r a g e RT f o r e a c h i t e m b ase d on a p p r o x i m a t e l y 204 o b s e r v a t i o n s . S i m i l a r l y , a n a v e r a g e a c c u r a c y was found f o r e a c h item b a se d on t h e t a r g e t and c a t c h t r i a l s f o r t h e s u b j e c t s i n t h e a c c u r a c y e x p e r i m e n t o f S t u d y 1 and t h e p r e c u e v e r s u s p o s t c u e e x p e r i m e n t o f S t u d y 2. The a v e r a g e a c c u r a c y o f e a c h item was b a s e d on 1 5 0 o b s e r v a t i o n s . C o r r e l a t i o n s b et ween t h e t h r e e r a t i n g s , a v e r a g e RT, and a v e r a g e a c c u r a c y a r e shown i n T a b l e 4 . 4 . Two t h i n g s may be observed i n Table 4 . 4 . F i r s t , t h e c o r r e l a t i o n be tw e e n t h e a c c u r a c i e s and RTs of a l l items was .56. Therefore, despite t h e m a g n i t u d e of t h e o b s e r v e d d i f f e r e n c e s between RT and a c c u r a c y measures, b o t h e x p e r i m e n t a l p r o c e d u r e s a p p e a r t o r e v e a l a common p r o c e s s i n g component. T h i s w i l l become e v e n more e v i d e n t i n t h e - c o r r e l a t i o n a l a n a l y s e s ( t o be d i s c u s s e d i n C h a p t e r 5 ) which d e m o n s t r a t e t h a t b o t h item a c c u r a c y and RT t e n d t o show s i m i l a r c o r r e l a t i o n s w i t h v a r i o u s m e a s u r e s o f orthographic structure. The c o r r e l a t i o n s between item a c c u r a c y , RT, and t h e ratings are illuminating. Correlations between t h e two p e r c e p t u a l m eas u r es and t h e r a t i n g s a r e q u i t e h i g h . The p e r c e p t u a l m eas u r es and t h e r a t i n g s s h a r e 31% t o 53% common v a r i a n c e . Whereas t h e knowledge s t r u c t u r e s ta ppe d by t h e r a t i n g p r o c e d u r e s need n o t n e c e s s a r i l y r e l a t e t o t h e knowledge s t r u c t u r e i n f e r r e d from t h e p e r c e p t u a l t a s k s , i t i s e n c o u r a g i n g t o observe t h a t there does appear to be a lawful I t would ap p ear t h a t what one knows a b o u t correspondence. orthographic structure not only influences perception but a l s o i s amenable t o i n t e r r o g a t i o n by c o n s c i o u s p r o c e s s e s . A se c ond e n c o u r a g i n g a s p e c t o f t h i s o b s e r v a t i o n i s t h a t r a t i n g t a s k s and p e r c e p t u a l t a s k s may be r e g a r d e d a s c o n v e r g i n g m e a s u r e s o f o r t h o g r a p h i c s t r u c t u r e . I f b o t h t a p a common d a t a base of o r t h o g r a p h i c s t r u c t u r e knowledge, t h e n w e c a n r e f i n e o u r u n d e r s t a n d i n g o f t h i s knowledge s o u r c e by means of r a t i n g t a s k s a s well a s p e r c e p t u a l t a s k s . For t h e c o r r e l a t i o n a l a n a l y s e s i n C h a p t e r 5 , i t e m a c c u r a c i e s , R T s , and r a t i n g s a r e e a c h r e g a r d e d


Table 4 . 4

85

C o r r e l a t i o n s among a v e r a g e a c c u r a c y , a v e r a g e RT, and t h e t h r e e r e g u l a r i t y r a t i n g s f o r t h e 200 s t i m u l u s i tems

.

(1) (1) Average a c c u r a c y

(2)

(3)

(4)

---

(2)

Average RT

(3)

R a t i n g w i t h o u t words

.58*

-.56*

--

(4)

R a t i n g w i t h pseudowords

.72

-.61

.97

--

(5)

R a t i n g w i t h words

.73

-.60

.97

.97

*

(5)

-.56

C o r r e l a t i o n based on t h e 1 6 0 anagrams o n l y , c o r r e l a t i o n s b a s e d on a l l 200 s t i m u l u s items.

--

all

other

as

r e l a t e d c o l l a t e r a l dependent measures p o t e n t i a l l y r e v e a l i n g a common o r t h o g r a p h i c s t r u c t u r e component.

STUDY 9:

POSITIONAL-FREQUENCY RATINGS

The r a t i n g s o f S t u d y 8 i n d i c a t e t h a t s u b j e c t s , when g i v e n r e l a t i v e l y n e u t r a l i n s t r u c t i o n s , b a s e t h e i r r a t i n g s more on r e g u l a r i t y than on positional f r e q u e n c y . B e f o r e we c a n conclude t h a t the r e a d e r ' s conscious knowledge is b e s t r e p r e s e n t e d by r e g u l a r i t y , i t i s n e c e s s a r y t o d e t e r m i n e w h e t h e r r e s p o n d on t h e b a s i s o f s u b j e c t s c a n be i n s t r u c t e d t o positional-frequency information. Accordingly, the rating e x p e r i m e n t w i t h o n l y 160 anagrams was r e p l i c a t e d b u t now t h e s u b j e c t s were g i v e n s p e c i f i c p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s . The i n s t r u c t i o n s e x p l a i n e d t h e c o n c e p t o f p o s i t i o n a l f r e q u e n c y a l o n g w i t h r e l e v a n t e x a m p l e s and t o l d t h e s u b j e c t s t o r a t e t h e i t e m s e x p l i c i t l y on t h i s basis. The e x a c t i n s t r u c t i o n s ,

CHAPTER 4

86

method, and p r o c e d u r e a r e g i v e n i n t h e Appendix 4 . 9 . Except f o r t h e i n s t r u c t i o n s , t h e procedure r e p l i c a t e d t h e previous r a t i n g experiment t h a t gave i n s t r u c t i o n s with r e s p e c t t o t y p i c a l i t y o f E n g l i s h s p e l l i n g . The r e s u l t s and d e t a i l e d a n a l y s e s a r e g i v e n i n Appendix 4 . 9 . Figure 4 . 2 1 g i v e s t h e r e s u l t s of t h i s experiment s t r e s s i n g p o s i t i o n a l f r e q u e n c i e s a l o n g w i t h t h e r e s u l t s of t h e p r e v i o u s e x p e r i m e n t s t r e s s i n g t y p i c a l i t y . The r e s u l t s show t h a t t h e similar with both sets of r a t i n g r e s p o n s e s were v e r y i n s t r u c t i o n s . However, p o s i t i o n a l f r e q u e n c y d i d m a k e more of a contribution with positional-frequency i n s t r u c t i o n s than with t y p i c a l i t y i n s t r u c t i o n s . O v e r a l l , s u b j e c t s tended t o rate high positional-frequency items a s slightly higher t h a n low positional-frequency items to a greater degree with positional-frequency instructions than with typicality i n s t r u c t i o n s . A l s o , t h e e f f e c t of r e g u l a r i t y on t h e judgm e nts

9-

876-

6

a

54-

32-

, ..

...

"

1I

Figure 4.21

TLPblfiY Poeltlonal Frequency

D-.-..O

I

1

I

I

R a t i n g s from 1 0 ( mo s t l i k e E n g l i s h ) t o l i k e E n g l i s h ) a s a f u n c t i o n of d i s p l a y typicality instructions (Study positional-frequency i n s t r u c t i o n s (Study

1 (least type for 8) and 9).


87

was s l i g h t l y a t t e n t u a t e d w i t h p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s relative t o typicality instructions. The r a t i n g experiments indicate that orthographic s t r u c t u r e i n terms o f r e g u l a r i t y a p p e a r s t o b e more c o n s c i o u s l y of positional available than structure in terms f r e q u e n c y . S u b j e c t s t e n d t o r a t e r e g u l a r items a s most l i k e E n g l i s h and i r r e g u l a r items a s l e a s t l i k e E n g l i s h r e g a r d l e s s o f w h e t h e r t h e y were g i v e n t y p i c a l i t y i n s t r u c t i o n s O K p o s i t i o n a l frequency i n s t r u c t i o n s . One limitation in the rating e x p e r i m e n t s may b e t h a t s u b j e c t s t e n d t o r a t e t h e items on t h e b a s i s of r e g u l a r i t y r e g a r d l e s s of t h e i n s t r u c t i o n s t h a t a r e g i v e n . T h e r e f o r e , a more d i r e c t i n d e x of t h e p s y c h o l o g i c a l r e a l i t y o f t h e s e two c o n c e p t s a s d e s c r i p t i o n s o f o r t h o g r a p h i c S t r u c t u r e should be obtained.

STUDY

la:

REGULARITY VERSUS POSITIONAL-FREQUENCY JUDGMENTS

I n o r d e r t o o b t a i n a more d i r e c t i n d e x of o r t h o g r a p h i c S t r u c t u r e , p r e c i s e r e g u l a r i t y i n s t r u c t i o n s were c o n t r a s t e d w i t h precise positional-frequency instructions. I t e m s from e a c h o f t h e f o u r t y p e s o f 1 6 0 anagrams w e r e p a i r e d w i t h e a c h o t h e r s u c h t h a t items o f one t y p e w e r e p a i r e d w i t h items o f t h e same t y p e o r w i t h items o f t h e o t h e r t y p e s . Some s u b j e c t s were g i v e n p a i r s o f items and a s k e d t o p i c k t h e i t e m from e a c h p a i r t h a t was most r e g u l a r . O t h e r s u b j e c t s were g i v e n t h e same p a i r s and a s k e d t o p i c k t h e i t e m t h a t was h i g h e s t i n t e r m s o f p o s i t i o n a l f r e q u e n c y . The i n s t r u c t i o n s , method, pKOCedUKe, and r e s u l t s a r e g i v e n i n Appendix 4 . 1 0 . T h i s experiment allowed a d i r e c t a s s e s s m e n t o f t h e r e l a t i v e w e i g h t c a r r i e d by o r t h o g r a p h i c r e g u l a r i t y and p o s i t i o n a l f r e q u e n c y i n t h e r e a d e r ' s e v a l u a t i o n o f o r t h o g r a p h i c s t r u c t u r e . The j u d g m e n t s o f t h e s e two g r o u p s o f s u b j e c t s were t a b u l a t e d a s t h e p r o p o r t i o n of times t h e y c h o s e a n item from one c a t e g o r y when i t was p a i r e d w i t h a n item from a n o t h e r c a t e g o r y . These r e s u l t s a r e p r e s e n t e d a s T a b l e 4.5 where t h e c e l l s o f t h e t a b l e g i v e t h e p r o p o r t i o n of times a n i t e m from t h e column c a t e g o r y was s e l e c t e d when p a i r e d w i t h a n item from t h e T O W c a t e g o r y . B e f o r e d i s c u s s i n g t h e a c t u a l r e s u l t s i n T a b l e 4 . 5 , i t is i n s t r u c t i v e t o h y p o t h e s i z e how t h i s t a b l e s h o u l d h a v e t u r n e d o u t i f t h e s u b j e c t s i n t h e two c o n d i t i o n s had a c o m p l e t e knowledge o f r e g u l a r i t y and p o s i t i o n a l f r e q u e n c y and had a p p l i e d t h i s knowledge i n a c c o r d a n c e w i t h t h e i n s t r u c t i o n s . Whenever t h e two items d i f f e r e d on t h e d i m e n s i o n r e l e v a n t f o r

CHAPTER 4

88

Table 4.5

Paired-judgment preferences for the 200 stimuli under regularity and positional-frequency instructions. Cells represent proportion of times the column item was chosen over the row item. The numbers in parentheses give the hypothetical outcomes assuming that the subject had knowledge of both dimensions and followed instructions. Regularity Instructions R- H

R- H

R- L

I-H

I-L

.475 (.5)

R- L

(.5)

,693

.445 C.5)

I-H

.910 (1.0)

.a77 (1.0)

.523 (.5)

I-L

.938 11.0)

.908 (1.0)

(.5)

.509

.518 (.5)

Positional Frequency Instructions R- H

R-H

.527 (.5)

R-L

.704 (1.0)

I-H

.866 (-5)

I-L

.953 (1.0)

R- L

I-H

I-L

.488 (.5)

.740 (.0) .a95 (.5)

.525 (.5)

.687 (1.0)

.494 (.5)


T a b l e 4.6

89

Chi-square f o r t h e two p r e d i c t e d o u t c o m e s a g a i n s t t h e observed outcomes f o r t h e two i n s t r u c t i o n c o n d i t i o n s i n study 10. P r e d i c t e d Outcome

Instructions

Regularity

Positional Frequency

Regularity

93.63

1561.26

P o s i t i o n a l Frequency

258.90

1367.50

t h e judgment, t h e s u b j e c t s s h o u l d have always chosen t h e " c o r r e c t item," o n t h a t d i m e n s i o n , i . e . , t h e one t h a t was more the one that was higher in positional r e g u l a r or frequency. Whenever t h e two items were a t e q u i v a l e n t l e v e l s o n t h e r e l e v a n t dimension, the s u b j e c t s s h o u l d have chosen i n d i f f e r e n t l y between them. T h e s e "perfect" hypothetical outcomes a r e a l s o shown i n T a b l e 4.5. Comparing t h e two p a n e l s o f T a b l e 4.5 we o b s e r v e t h a t f o r instructions, subjects made c h o i c e s more both sets of c o n s i s t e n t w i t h t h e a p p l i c a t i o n of r e g u l a r i t y t h a n w i t h t h e a p p l i c a t i o n o f p o s i t i o n a l f r e q u e n c y . I n o r d e r t o assess how w e l l t h e r e s u l t s conformed t o what would be e x p e c t e d from p e r f e c t knowledge and u t i l i z a t i o n o f r e g u l a r i t y o r p o s i t i o n a l f r e q u e n c y , t h e two p r e d i c t e d o u t c o m e s were compared w i t h t h e a c t u a l outcomes under b o t h i n s t r u c t i o n c o n d i t i o n s . T a b l e 4.6 g i v e s t h e Chi-square values for c o m p a r i s o n s o f t h e two p r e d i c t e d outcomes a g a i n s t t h e observed outcomes f o r b o t h instruction conditions. The v a l u e ' s s u p p o r t t h e i n t e r p r e t a t i o n t h a t t h e s u b j e c t s ' p e r f o r m a n c e is more a d e q u a t e l y d e s c r i b e d by r e g u l a r i t y than p o s i t i o n a l frequency. However, t h o u g h s u b j e c t s a p p e a r t o be u s i n g m o s t l y r e g u l a r i t y a s a b a s i s o f t h e i r ratings, i n neither case did t h e ratings indicate t h a t only r e g u l a r i t y was u s e d . I f we compare t h e two p a n e l s o f T a b l e 4.5 t o e a c h o t h e r , we s e e t h a t t h e r e was a n a d d i t i o n a l c o n t r i b u t i o n of p o s i t i o n a l frequency when subjects were e x p l i c i t l y i n s t r u c t e d t o b a s e t h e i r judgments on f r e q u e n c y . E v i d e n t l y , s u b j e c t s c a n modify t h e i r j u d g m e n t s s l i g h t l y when g i v e n e x p l i c i t i n s t r u c t i o n s t o attend t o p o s i t i o n a l frequency.

CHAPTER 4

SUMMARY OF OVERT JUDGMENT EXPERIMENTS The e x p e r i m e n t s s u p p o r t t h e i d e a t h a t knowledge of o r t h o g r a p h i c s t r u c t u r e is c o n s c i o u s l y a v a i l a b l e and c a p a b l e of report. S u b j e c t s a r e r e l a t i v e l y good a t a s s i g n i n g r a t i n g s on t h e b a s i s of r u l e - g o v e r n e d r e g u l a r i t y b u t r e l a t i v e l y poor a t rating items on the basis of statistical redund a n c y . S i m i l a r l y , c h o o s i n g which of a p a i r of items i s more r e g u l a r is r e l a t i v e l y e a s y wh er eas c h o o s i n g which is more f r e q u e n t is n e a r l y i m p o s s i b l e . The p o s t hoc c o r r e l a t i o n s i n C h a p t e r 5 w i l l a l l o w a more d i r e c t and b r o a d e r a s s e s s m e n t of t h e n a t u r e of t h e knowledge u t i l i z e d i n o v e r t judgm e nts of letter strings.

APPENDIX 4 . 1

91

Appendix 4 . 1 D e t a i l s o f Method, P r o c e d u r e , and R e s u l t s o f S t u d y 1: I n i t i a l R e p l i c a t i o n

Method S u b j e c t s . One g r o u p of 14 I n t r o d u c t o r y Psyc hology s t u d e n t s p a r t i c i p a t e d i n t h e p o s t c u e a c c u r a c y t a s k f o r an t,t,>-, a d a y on e a c h o f 2 c o n s e c u t i v e d a y s . The d a t a from t h r c a d d i t i o n a l s u b j e c t s were l o s t d u e t o computer s y s t e m f , i i l u r S i x o t h e r s u b j e c t s were t e s t e d b u t t h e i r d a t a were n o t i n c l i r l e d b e c a u s e o f i n a d m i s s i b l e o v e r a l l a c c u r a c y . Another g r o u p o f 14 IntKOdUCtOKy P s y ch o l o g y s t u d e n t s p a r t i c i p a t e d f o r a n hour e a c h d a y on 2 c o n s e c u t i v e d a y s i n t h e p r e c u e RT t a s k . A l l s u b j e c t s i n both t a s k s passed a p r e l i m i n a r y v i s i o n t e s t e s t a b l i s h i n g a t l e a s t 20/40 a c u i t y f o r b o t h e y e s . A l l s u b j e c t s w e re awarded r e s e a r c h p a r t i c i p a t i o n c r e d i t t o war d t h e i r p s y c h o l o g y g r a d e . S t i m u l i . A l i s t i n g of t h e 100 h i g h e s t and 108 l o w e s t summed single-letter positional-frequency anagrams w e re o b t a i n e d f o r s e v e r a l hundred common s i x - l e t t e r words s e l e c t e d from t h e Kucera and F r a n c i s ( 1 9 6 7 ) word l i s t . The l i s t i n g s o f t h e anagrams were p r o d u ced by a computer program which g e n e r a t e d a l l 720 p o s s i b l e p e r m u t a t i o n s f o r e a c h s i x - l e t t e r word. The p o s i t i o n a l f r e q u e n c y f o r e a c h p e r m u t a t i o n was computed from t h e Mayzner and T r e s s e l t ( 1 9 6 5 ) s i n g l e - l e t t e r c o u n t s f o r s i x - l e t t e r words by summing t h e p o s i t i o n - d e p e n d e n t f r e q u e n c y for e a c h l e t t e r . Words w i t h r e p e a t e d l e t t e r s w e re n o t u se d . From t h e 720 anagrams f o r e a c h s i x - l e t t e r word, two were c h o s e n w i t h h i g h - p o s i t i o n a l f r e q u e n c i e s and two w e re chosen with low-positional f r e q u e n c i e s . Within each frequency p a i r , o n e member was o r t h o g r a p h i c a l l y r e g u l a r ahd t h e o t h e r o r t h o g r a p h i c a l l y i r r e g u l a r . The rules used f o r judging r e g u l a r i t y a r e l i s t e d i n Appendix 4 . 1 A . L i s t e d i n Appendix 4.18 a r e t h e 200 s t i m u l u s i t e m s - - t h e 40 words and t h e 4 anagrams o f e a c h word. One-hundred t w e n t y p r a c t i c e s t i m u l i were g e n e r a t e d from 2 4 a d d i t i o n a l words. The se i t e m s w e re n o t a s e v e n l y matched f o r r e g u l a r i t y and p o s i t i o n a l f r e q u e n c y a s t h e e x p e r i m e n t a l i t e m s and a few c o n t a i n e d r e p e a t e d l e t t e r s . Two o c c u r r e n c e s o f e a c h o f t h e 1 2 0 p r a c t i c e s t i m u l i were randomized f o r e a c h s u b j e c t ' s p r a c t i c e s e q u e n c e and two o c c u r r e n c e s o f e a c h of t h e 200 e x p e r i m e n t a l s t i m u l i were randomized f o r e a c h s u b j e c t ' s e x p e r i m e n t a l s e q u e n c e . One o c c u r r e n c e was t e s t e d a s a t a r g e t t r i a l and one a s a c a t c h

.

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CHAPTER 4

t r i a l . On t a r g e t t r i a l s . t h e l e t t e r was s e l e c t e d randomly w i t h r e p l a c e m e n t from t h e s i x l e t t e r s i n t h e t e s t s t r i n g . For c a t c h t r i a l s , a t a r g e t was s e l e c t e d randomly from t h e s e t o f 26 l e t t e r s w e i g h t e d by t h e i r p r o b a b i l i t y o f o c c u r r e n c e i n t h e s t i m u l u s s e t . If t h e s e l e c t e d l e t t e r was p r e s e n t i n t h e d i s p l a y s t r i n g , a d d i t i o n a l d r a w i n g s w i t h r e p l a c e m e n t w e r e made u n t i l a n a p p r o p r i a t e t a r g e t l e t t e r was s e l e c t e d . The l e t t e r s 1, k, 9, 5 , and 2 d i d n o t o c c u r i n t h e e x p e r i m e n t a l s t i m u l u s s t r i n g s and t h e r e f o r e were n e v e r t e s t e d . The d i s p l a y s were p r e s e n t e d on a B e e h i v e model %paratus. v i d e o computer t e r m i n a l u n d e r t h e c o n t r o l o f a H a r r i s DC6024/5 t h e terminal's c o m p u t e r . Hardware m o d i f i c a t i o n s p e r m i t t e d v i d e o t o b e t u r n e d on and o f f w i t h p r o g r a m - g e n e r a t e d control s i g n a l s . The d i s p l a y s t r i n g s were l o a d e d i n t o t h e memory b u f f e r o f t h e t e r m i n a l w i t h t h e v i d e o o f f and t h e n t h e v i d e o was t u r n e d on f o r t h e a p p r o p r i a t e e x p o s u r e d u r a t i o n . The Beehive employs a P4, b l u e - w h i t e phosphor which d e c a y s t o . l % o f maximum l u m i n a n c e w i t h i n 32 msec. The e x p e r i m e n t was c o n d u c t e d i n a p a r t i a l l y d a r k e n e d room t o e n h a n c e image contrast. A l l s i n g l e - l e t t e r t a r g e t and l e t t e r - s t r i n g t e s t d i s p l a y s were p r e s e n t e d i n l o w e r c a s e l e t t e r s . The B e e h i v e u s e s a 5 x 7 d o t m a t r i x , 2.5 mm w i d e x 5 mm h i g h , A t t h e a v e r a g e s u b j e c t ' s v i e w i n g d i s t a n c e of a p p r o x i m a t e l y 38 cm, t h e s i x - l e t t e r s t r i n g s s u b t e n d e d a h o r i z o n t a l v i s u a l a n g l e o f 2.25 d e g r e e s and a v e r t i c a l v i s u a l a n g l e of . 7 5 d e g r e e . The d i s p l a y s were p r e s e n t e d i n t h e upper c e n t e r o f t h e s c r e e n . The s i n g l e - l e t t e r t a r g e t was p o s i t i o n e d t o a p p e a r t h r e e c h a r a c t e r p o s i t i o n s t o t h e l e f t of t h e s t r i n g d i s p l a y , a h o r i z o n t a l v i s u a l a n g l e s e p a r a t i o n of .75 d e g r e e . To a c h i e v e a r a p i d and c o n t r o l l e d p r e s e n t a t i o n r a t e , t h e e n t i r e d i s p l a y s e q u e n c e f o r a n item was d i s p l a y e d b e n e a t h a c a r d b o a r d mask a f f i x e d t o t h e f a c e o f t h e c a t h o d e r a y t u b e ( C R T ) . A r e c t a n g u l a r window i n t h e mask s e r v e d a s a f i x a t i o n box and p e r m i t t e d o n l y t h e d e s i r e d p o r t i o n o f t h e d i s p l a y t o be o b s e r v e d . -___ Procedure. The s u b j e c t s i n the a c c u r a c y t a s k were informed t h a t t h e e x p o s u r e d u r a t i o n would b e b r i e f and would b e a d j u s t e d d u r i n g t h e s e s s i o n t o m a i n t a i n a n a c c u r a c y o f 75%. A t r i a l began w i t h t h e p r e s e n t a t i o n o f t h e s i x - l e t t e r stimulus string for a brief duration. After t h e appropriate exposure duration, t h e d i s p l a y was s c r o l l e d upward o n t h e CRT r e p l a c i n g t h e s t r i n g w i t h a masking s t i m u l u s c o n s i s t i n g o f s i x u p p e r c a s e -Xs. The masking s t i m u l u s was p r e s e n t e d f o r 208 msec t h e n scrolled again t o present the t a r g e t l e t t e r . The t a r g e t l e t t e r remained i n v i e w u n t i l t h e s u b j e c t r e s p o n d e d , a t which t i m e t h e

APPENDIX 4 . 1

93

d i s p l a y was t e r m i n a t e d and a 500 msec i n t e r t r i a l i n t e r v a l begun. The e x p o s u r e d u r a t i o n o f t h e t e s t s t r i n g was i n d i v i d u a l l y determined for each subject during the practice t r i a l s . Because o f t h e 60 Hz r e f r e s h r a t e o f t h e CRT o n e r e f r e s h c y c l e ( 1 6 . 7 msec) was c h o s e n a s t h e b a s i c t i m e unit. The number of c y c l e s needed t o a c h i e v e a n o v e r a l l a c c u r a c y l e v e l o f 75% was d e t e r m i n e d o n - l i n e u s i n g a v e r s i o n of the adaptive PEST algorithm (Taylor & Creelman, 1 9 6 7 ) . Exposure d u r a t i o n was not changed during the e x p e r i m e n t a l t r i a l s . The i n i t i a l e x p o s u r e d u r a t i o n was 20 c y c l e s ( 3 3 4 msec) f o r a l l s u b j e c t s . The r a n g e o f e x p o s u r e s needed by t h e 1 4 s u b j e c t s f o r 75% a c c u r a c y was 1 t o 1 2 c y c l e s w i t h a median e x p o s u r e d u r a t i o n o f 3 c y c l e s ( 5 0 msec). The s u b j e c t s i n t h e RT t a s k were i n s t r u c t e d t o r e s p o n d a s A l l s u b j e c t s were a l s o r a p i d l y and a s a c c u r a t e l y a s p o s s i b l e . t o l d t h a t o n e - h a l f o f t h e t r i a l s would be t a r g e t t r i a l s and one-half would b e c a t c h t r i a l s . The d i s p l a y s e q u e n c e was A t r i a l began w i t h the a l t e r e d t o accommodate t h e p r e c u i n g . p r e s e n t a t i o n of t h e t a r g e t l e t t e r a t t h e l e f t of t h e f i x a t i o n window f o r 500 msec. The t a r g e t l e t t e r was t h e n t e r m i n a t e d and 1 s e c l a t e r t h e s t i m u l u s s t r i n g was d i s p l a y e d . The s t i m u l u s remained i n view u n t i l t h e s u b j e c t r e s p o n d e d , a t which time t h e A d i s p l a y was t e r m i n a t e d and a 500 msec i n t e r v a l begun. masking f i e l d was n o t u s e d . To a c q u a i n t s u b j e c t s i n b o t h t h e a c c u r a c y and RT t a s k s w i t h t h e r e s p o n s e p r o c e d u r e and v i s u a l d i s p l a y , e a c h d a y ' s s e s s i o n began w i t h 10 t r i a l s c o n s i s t i n g o f o n l y t h e word YES o r NO i n s t e a d o f t h e d i s p l a y s t r i n g . No t a r g e t l e t t e r was presented. The s u b j e c t s p r e s s e d t h e c o r r e s p o n d i n g l y l a b e l e d response buttons. The YES r e s p o n s e was a s s i g n e d t o e a c h s u b j e c t ' s p r e f e r r e d hand ( r i g h t hand f o r 9 o f t h e 1 4 s u b j e c t s i n t h e a c c u r a c y t a s k ; 1 3 o f t h e 1 4 s u b j e c t s i n t h e RT t a s k ) . The "yes-no" t r i a l s were f o l l o w e d by t h e 240 p r a c t i c e t r i a l s and t h e 400 e x p e r i m e n t a l t r i a l s . The p r a c t i c e t r i a l s were d i v i d e d i n t o f o u r 60 t r i a l b l o c k s and t h e e x p e r i m e n t a l t r i a l s w e r e d i v i d e d i n t o f i v e 8 0 - t r i a l b l o c k s . A t t h e end o f e a c h b l o c k t h e s u b j e c t was g i v e n a n o p p o r t u n i t y t o r e s t and r e c e i v e d f e e d b a c k i n t h e form o f a p e r c e n t c o r r e c t s c o r e o r RT and e r r o r r a t e , a s a p p r o p r i a t e , for t h e p r e c e d i n g b l o c k . A l l s u b j e c t s were t e s t e d i n two s u c h s e s s i o n s s c h e d u l e d on consecutive days.

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O r t h o g r a p h i c s t r u c t u r e . Analyses o f v a r i a n c e were c a r r i e d o u t on t h e a v e r a g e p e r c e n t a g e c o r r e c t f o r e a c h s u b j e c t f o r e a c h of t h e 5 d i s p l a y t y p e s and t a r g e t v e r s u s c a t c h t r i a l s . For t h e a c c u r a c y t a s k , t h e main e f f e c t o f d i s p l a y t y p e was s i g n i f i c a n t , F (4, 52) = 8 2 . 5 6 , E < . 0 0 1 , and t h e d i f f e r e n c e s among t h e s e c o n d i t i o n s were t e s t e d w i t h s p e c i f i c c o n t r a s t s . A c c u r a c y f o r words was 1 2 % g r e a t e r t h a n f o r t h e b e s t pseudoword items ( r e g u l a r - h i g h ) , E (1, 52) = 40.54, E < .001. Three o r t h o g o n a l c o n t r a s t s analogous t o a 2 x 2 a n a l y s i s of v a r i a n c e f o r t h e f o u r nonword d i s p l a y t y p e s r e v e a l e d t h a t t h e r e g u l a r s t r i n g s were j u d g e d 8 % more a c c u r a t e l y t h a n i r r e g u l a r s t r i n g s , E (1, 52) = 7 . 0 5 , E < .01. High p o s i t i o n a l - f r e q u e n c y s t r i n g s were judged 5 % more accurately t h a n low p o s i t i o n a l - f r e q u e n c y s t r i n g s , E (1, 5 2 ) = 7.05, E < .01. The i n t e r a c t i o n o f p o s i t i o n a l f r e q u e n c y and r e g u l a r i t y was n o t s i g n i f i c a n t , 2 (1, 52) = 3 . 2 0 , p > .05. For t h e RT a n a l y s i s , RTs f o r i n c o r r e c t t r i a l s and c o r r e c t t r i a l R T s which e x c e e d e d 2 sec ( l e s s t h a n .2% o f t h e d a t a ) w e r e e x c l u d e d from t h e a n a l y s e s l e a v i n g a p p r o x i m a t e l y 76 o f 8 0 p o s s i b l e o b s e r v a t i o n s p e r c e l l . For t h e RT d a t a , t h e r e was a l s o a s i g n i f i c a n t main e f f e c t of d i s p l a y t y p e , 1 ( 4 , 5 2 ) = 17.16, E < .001. T h i s main e f f e c t was examined w i t h t h e same s e t o f s p e c i f i c c o n t r a s t s . The 7 msec a d v a n t a g e f o r words o v e r r e g u l a r - h i g h pseudowords was n o t s i g n i f i c a n t , E (1, 52) = 2 . 0 1 , E > .10. R e g u l a r items were j u d g e d 23 msec f a s t e r t h a n i r r e g u l a r items, a s i g n i f i c a n t d i f f e r e n c e , E (1, 52) = 9 . 5 4 , E < .005. N e i t h e r t h e 4 msec d i f f e r e n c e b e t w e e n h i g h and low p o s i t i o n a l f r e q u e n c y n o r t h e i n t e r a c t i o n o f r e g u l a r i t y and p o s i t i o n a l f r e q u e n c y were s i g n i f i c a n t , b o t h Es < 1. Error The main p e r c e n t a g e s were a n a l y z e d s i m i l a r l y t o t h e RTs. e f f e c t o f d i s p l a y t y p e was n o t s i g n i f i c a n t , E ( 4 , 5 2 ) = 1 . 1 3 . test for the e f f e c t s of S i m i l a r i t y a n a l y s e s . To s i m i l a r i t y between t h e t a r g e t l e t t e r and t h e l e t t e r s i n t h e d i s p l a y , t h e d a t a were f i r s t pooled a c r o s s d i s p l a y t y p e s . Each t r i a l ' s t a r g e t l e t t e r was c l a s s i f i e d a c c o r d i n g t o which l e t t e r s i n t h e d i s p l a y were l i k e l y t o be s e e n a s v e r y s i m i l a r t o t h e t a r g e t . The c l a s s i f i c a t i o n was d e r i v e d from t h e l o w e r c a s e s i n g l e - l e t t e r c o n f u s a b i l i t y s t u d y p u b l i s h e d by Bouma ( 1 9 7 1 ) . A l e t t e r was c o u n t e d a s s i m i l a r t o t h e t a r g e t l e t t e r i f t h e l e t t e r was e r r o n e o u s l y i d e n t i f i e d a s t h e t a r g e t more t h a n 5 % o f t h e time. T a b l e 4 . 2 p r e s e n t s t h e c l a s s i f i c a t i o n a c c o r d i n g t o t h i s a n a l y s i s . Each t r i a l was t h e n c l a s s i f i e d by t h e number o f n o n t a r g e t l e t t e r s i n t h e d i s p l a y t h a t were s i m i l a r t o t h e

APPENDIX 4 . 1

95

t a r g e t a c c o r d i n g t o t h i s c r i t e r i o n . Roughly 4 6 , 3 3 , 1 3 , and 1 % of each s u b j e c t ' s t r i a l s f e l l i n t o t h e c a t e g o r i e s z e r o , o n e , two, and t h r e e s i m i l a r l e t t e r s ( o t h e r t h a n t h e t a r g e t l e t t e r i t s e l f ) , respectively. For t h e a c c u r a c y t a s k d a t a , t h e e f f e c t of number s i m i l a r l e t t e r s was s i g n i f i c a n t . ( 3 , 39) = 7 . 1 4 , p < .001. Accuracy on t a r g e t t r i a l s i n c r e a s e d some w i t h i n c r e a s e s i n t h e number o f s i m i l a r l e t t e r s , w h e r e a s a c c u r a c y on c a t c h t r i a l s d e c r e a s e d s i g n i f i c a n t l y w i t h i n c r e a s e s i n t h e number o f s i m i l a r l e t t e r s , -F ( 3 , 3 9 ) = 22.28, p < .001. For t h e RT t a s k , i n c r e a s i n g t h e number of s i m i l a r l e t t e r s p r o d u c e d a s i g n i f i c a n t i n c r e a s e i n RT, E ( 3 , 39) = 4.41 < .01. The i n c r e a s e was c l e a r l y l a r g e r on c a t c h t r i a l s t h a n t a r g e t t r i a l s , E ( 3 , 39) = 3 . 1 3 , p < . 0 5 . T a r g e t - c a t c h d i f f e r e n c e s . For t h e a c c u r a c y t a s k , a c c u r a c y was g r e a t e r f o r c a t c h t r i a l s ( 8 4 % ) t h a n f o r t a r g e t t r i a l s ( 7 2 % ) . E (1, 1 3 ) = 1 9 . 6 5 , p < .001, and t h i s e f f e c t i n t e r a c t e d ( 4 , 52) = 8.14, < .001. O r t h o g r a p h i c with d i s p l a y types, s t r u c t u r e had a g r e a t e r e f f e c t on t a r g e t t h a n c a t c h t r i a l s . For t h e RT t a s k , t h e r e was a d i f f e r e n c e between t a r g e t and c a t c h t r i a l s . C a t c h t r i a l s w e r e 47 msec s l o w e r t h a n t a r g e t However, t h i s e f f e c t d i d t r i a l s , E (1, 1 3 ) = 4 2 . 5 5 , p < .001. Target-catch n o t i n t e r a c t w i t h d i s p l a y t y p e , 1( 4 , 52) = 1.49. d i f f e r e n c e s were a l s o r e f l e c t e d i n t h e e r r o r r a t e s i n t h e RT t a s k . T a r g e t t r i a l s e x p e r i e n c e d more e r r o r s ( 6 . 8 % ) t h a n d i d T h e r e was c a t c h t r i a l s ( 3 . 3 % ) , E (1, 1 3 ) = 29.88, p < .0001. no i n t e r a c t i o n w i t h d i s p l a y t y p e , E ( 4 , 52) = 1 . 2 4 .

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96

Appendix 4 . 1 A R u l e s f o r t h e S e l e c t i o n of O r t h o g r a p h i c a l l y R e g u l a r and I r r e g u l a r S t r i n g s T h e s e r u l e s were d e r i v e d by e x t e n d i n g t h e r u l e s g i v e n i n Venezky ( 1 9 7 0 ) , Venezky and Massaro ( 1 9 7 9 ) , and Massaro e t a l . ( 1 9 7 9 ) . Among a l l p o s s i b l e anagrams of a word, a l e t t e r s t r i n g was r e g a r d e d a s o r t h o g r a p h i c a l l y i r r e g u l a r i f i t c o n t a i n e d a t l e a s t one o f t h e f o l l o w i n g s p e l l i n g s : a. p h o n o l o g i c a l l y i l l e g a l ( i n E n g l i s h ) i n i t i a l or f i n a l c l u s t e r (e.g. , tlfies, i a s G ) . b. o r t h o g r a p h i c a l l y i l l e g a l s p e l l i n g for a n i n i t i a l or f i n a l c o n s o n a n t or c o n s o n a n t c l u s t e r ( e . g . , keagc, tlerav) c . a n i l l e g a l vowel s p e l l i n g ( e . g . , p r s a e d , n m t E ) . d . a p h o n o l o g i c a l l y i l l e g a l m e d i a l c l u s t e r ( e . g . , ilmpes, iGsa) L e t t e r s t r i n g s were r e g a r d e d a s r e g u l a r i f t h e y were p h o n o l o g i c a l l y l e g a l and c o n t a i n e d common vowel and c o n s o n a n t spellings.

.

.

APPENDIX 4 . 1 8

97

Appendix 4 . 1 B The 200 S t i m u l u s Items Used i n S t u d i e s 1 - 1 0 The items l i s t e d a r e i n columns a c c o r d i n g t o t y p e , where W word; R-H = r e g u l a r - l o w ; I-H = i r r e g u l a r - h i g h ; R-L = r e g u l a r - l o w ; and I - L = i r r e g u l a r - l o w . Each row c o n t a i n s a word and t h e f o u r anagrams g e n e r a t e d from i t .

=

Word

R- H -

a c tion amount answer barely belong breath bridge charge double famous finger garden gather glance hardly itself lawyer longer master modern

cainot mauton swaner blayer goblen thaber begr i d chager bodule foamus f er i n g nagred thager caleng hyr a l d siflet weraly logren tamer dormen

R-L

onicat otanum erswan bye K a1 glenob therab gredib greach edolub osafum gref i n gredan greath glecan hydra1 flesit l y e r aw gleron steram drenom

I-H aiocnt auotnm wnraes lbraey lnboeg bhrtea ierbgd ahcge r leoubd uaomf s rfnieg arnged hrtaeg lcnaeg yr ahld t l f ies rwlaey glnoer mr t a e s oermnd

I-L

icntoa nmtaou rnwesa r bleya ebgnlo rtbeha ebrgdi hreagc obdeul ofmsua efngr i ednrga grheta eclnga rdlhya eflsti e y r lwa egnrlo emr t s a rmedno

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98

APPENDIX 4 . 1 8 (COnt.)

Word

R- H -

R- L -

I-H -

I-L -

mother namely nearly permit player poetry purely reason remain result shared simple single spread stared stream travel trials turned winter

thomer manely lareny p r ime t rapley petory yulper sarone r amine surtel shread pimsel snigel p r ased sarted trames vartle s a r t il drunet t r iwen

therom lyeman nyelar trepim lyerap tyerop ryelup erosan amer i n tresul dreash ems1 i p glesin dresap dresat tresam treval t r isal tredun trewin

m rote h lmnaey lrnaey tmr i e p p l r aey yptoer lpyuer snaoer mr a i e n lrtues srdaeh ilmpes ilgnes p r saed srtaed mtraes avrlet iastlr rdnuet wrntei

hre tm o emnyla enyr l a rtpei m epylra erytpo erplyu rnseoa rnie m a elsrtu hsreda lsepmi nglesi dsepr a dtsera esrtma tlerav irltsa edtrnu rntewi

APPENDIX 4.2

99

Appendix 4.2 D e t a i l s o f Method, P r o c e d u r e , a n d R e s u l t s o f S t u d y 2 : Precue versus Postcue

Method Subjects. Eighteen I n t r o d u c t o r y Psychology s t u d e n t s , 8 m a l e and 1 0 f e m a l e , p a r t i c i p a t e d f o r a n h o u r e a c h d a y o n 2 c o n s e c u t i v e d a y s and r e c e i v e d r e s e a r c h p a r t i c i p a t i o n c r e d i t t o w a r d t h e i r p s y c h o l o g y g r a d e . The d a t a f r o m a n a d d i t i o n a l 1 2 s t u d e n t s was l o s t d u e t o m a c h i n e m a l f u n c t i o n s an d i n a d m i s s i b l e A l l s u b j e c t s passed a preliminary v i s i o n o v e r a l l accuracy. t e s t e s t a b l i s h i n g a t l e a s t 20/40 a c u i t y f o r b o t h e y e s . None o f t h e s u b j e c t s had s e r v e d i n a n y o f o u r p r e v i o u s e x p e r i m e n t s . ~S t i m u l i a n d a p p a r a t u s . The stimuli, a p p a r a t u s , and d i s p l a y s e q u e n c e f o r t h e p o s t c u e t a s k were i d e n t i c a l t o t h o s e For o f t h e a c c u r a c y t a s k o f S t u d y 1 d e s c r i b e d i n A p p en d i x 4 . 1 . t h e precue t a s k , a t r i a l began w i t h t h e p r e s e n t a t i o n o f t h e t a r g e t l e t t e r a t t h e l e f t o f t h e f i x a t i o n window f o r 5 0 0 msec. The t a r g e t l e t t e r was t h e n t e r m i n a t e d and 1 s e c l a t e r t h e was displayed for the appropriate exposure string duration. A f t e r d i s p l a y i n g t h e s t i m u l u s s t r i n g , t h e masking s t i m u l u s was s c r o l l e d i n t o v i e w a n d r e m a i n e d o n t h e s c r e e n u n t i l t h e s u b j e c t responded. The r a n g e o f e x p o s u r e d u r a t i o n s us ed f o r t h e p r e c u e t a s k was 1 t o 8 c y c l e s w i t h a m e d i a n o f 2 cycles. F o r t h e p o s t c u e t a s k t h e r a n g e was 2 t o 11 c y c l e s w i t h a median of 3 c y c l e s . Procedure. Half t h e s u b j e c t s r e c e i v e d t h e precue t a s k t h e f i r s t day and t h e p o s t c u e t a s k t h e second day. For t h e r e m a i n i n g s u b j e c t s t h i s o r d e r was r e v e r s e d . Each d a y t h e a p p r o p r i a t e t a s k w a s e x p l a i n e d t o t h e s u b j e c t and p e r f o r m a n c e a c c u r a c y was s t r e s s e d . S u b j e c t s were t o l d t h a t o n e - h a l f o f t h e t r i a l s would b e t a r g e t a n d o n e - h a l f would b e c a t c h t r i a l s . A s i n S t u d y 1, t h e t e s t s e q u e n c e c o n s i s t e d o f 1 0 "y es- n o " t r i a l s , 4 6 0 - t r i a l p r a c t i c e b l o c k s d u r i n g w h i c h e x p o s u r e w as a d j u s t e d w i t h t h e a d a p t i v e a l g o r i t h m , a n d ,5 8 0 - t r i a l e x p e r i m e n t a l b l o c k s A l l subjects d u r i n g which t h e e x p o s u r e remained c o n s t a n t . r e s p o n d e d " y e s " t o t a r g e t t r i a l s w i t h t h e i r p r e f e r r e d h an d ( r i g h t hand f o r 1 7 o f t h e 1 8 s u b j e c t s ) .

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Re s u l t s Orthographic s t r u c t u r e . An a n a l y s i s o f v a r i a n c e was c o m p u t e d from t h e s u b j e c t s ' mean a c c u r a c i e s f o r t h e 2 x 2 x 5 combinations of type of task (precue versus postcue) , t r i a l (word, type ( t a r g e t v e r s u s c a t c h ) , and d i s p l a y c o n d i t i o n regular-high, regular-low, i r r e g u l a r - h i g h , and irregular-low) The m a i n e f f e c t o f d i s p l a y t y p e was s i g n i f i c a n t , E ( 4 , 6 8 ) = 63.57, E < . 0 0 1 , a n d p l a n n e d c o m p a r i s o n s were p e r f o r m e d a s i n S t u d y 1. Words were j u d g e d 8 % m o r e a c c u r a t e l y t h a n t h e regular-high p o s i t i o n a l - f r e q u e n c y n o n w o r d s , E (1, 6 8 ) = 3 4 . 8 8 , E < .001. F o r t h e a n a g r a m d i s p l a y t y p e s , r e g u l a r s t r i n g s were j u d g e d 6 % more a c c u r a t e l y t h a n i r r e g u l a r s t r i n g s , (1, 6 8 ) = 4 2 . 0 1 , E < .001. H i g h p o s i t i o n a l - f r e q u e n c y s t r i n g s were j p d g e d 5 % more a c c u r a t e l y t h a n l o w p o s i t i o n a l - f r e q u e n c y s t r i n g s , E (1, 6 8 ) = 3 0 . 6 3 , E < .001. R e g u l a r i t y and p o s i t i o n a l f r e q u e n c y d i d The i n t e r a c t i o n o f n o t i n t e r a c t , E (1, 6 8 ) = 1 . 7 1 , p > .15. t y p e o f t a s k w i t h d i s p l a y c o n d i t i o n was s i g n i f i c a n t , E ( 4 , 6 8 ) = 2.99, p < .024. T h e o v e r a l l e f f e c t s o f s t r u c t u r e were g r e a t e r i n t h e postcue than t h e precue task. Although accuracy f o r i r r e g u l a r - l o w p o s i t i o n a l f r e q u e n c y was e q u i v a l e n t i n t h e two t a s k s , the trends diverged s t e a d i l y with increasing s t r u c t u r e s o t h a t a c c u r a c y f o r w o r d s was 6 % g r e a t e r in the postcue than t h e precue task. No o t h e r i n t e r a c t i o n s a p p r o a c h e d significance. S i m i l a r i t y a n a l y s e s . A p o s t h o c s i m i l a r i t y a n a l y s i s was performed a s i n t h e p r e v i o u s experiment. The a n a l y s i s o f variance included a s f a c t o r s t h e type of t a s k , t h e type of t r i a l ( t a r g e t v e r s u s c a t c h ) , a n d t h e number o f s i m i l a r l e t t e r s . T h e r e was a m a i n e f f e c t o f t h e number o f s i m i l a r l e t t e r s , (3, 51) = 2.86, E < . 0 5 , and a s i g n i f i c a n t i n t e r a c t i o n w i t h c a t c h and t a r g e t t r i a l s , 1 ( 3 , 5 1 ) = 3 . 5 8 , p < . 0 2 5 . Relative t o the p r e v i o u s a c c u r a c y e x p e r i m e n t shown i n F i g u r e 4 . 1 0 , t h e p r e s e n t r e s u l t s shown i n F i g u r e 4 . 1 3 r e v e a l e d much s m a l l e r d e c r e a s e s o n c a t c h t r i a l s and l i t t l e c h a n g e on t a r g e t t r i a l s w i t h i n c r e a s e s The same r e s u l t s were i n t h e number o f s i m i l a r l e t t e r s . o b s e r v e d i n t h e p r e c u e and p o s t c u e t a s k s . N e i t h e r t h e main e f f e c t o f Target versus catch trials. type of task (precue versus postcue) nor t r i a l type (target their v e r s u s c a t c h ) was s i g n i f i c a n t ( b o t h E s < 1 ) ; h o w e v e r , (1,17) = 8 . 6 3 , E < . 0 0 9 . It is i n t e r a c t i o n was s i g n i f i c a n t , apparent from F i g u r e 4 . 1 4 t h a t s u b j e c t s were more a c c u r a t e o n t a r g e t than catch t r i a l s i n the precue condition, whereas t h i s b i a s was r e v e r s e d i n t h e p o s t c u e t a s k .

.

z

APPENDIX 4.3

101

Appendix 4.3 D e t a i l s of t h e Method, P r o c e d u r e , and R e s u l t s o f S t u d y 3: Mixed-Case

Method Subjects. E i g h t e e n I n t r o d u c t o r y Psychology s t u d e n t s , 3 m a l e and 1 5 f e m a l e s , p a r t i c i p a t e d f o r a n hour e a c h d a y on 2 consecutive days and received research participation c r e d i t . One a d d i t i o n a l s u b j e c t was l o s t for f a i l u r e t o complete t h e ex p er i men t . A l l s u b j e c t s passed a p r e l i m i n a r y v i s i o n t e s t w i t h a t l e a s t 20/40 a c u i t y f o r b o t h e y e s and no s u b j e c t had s e r v e d i n p r e v i o u s e x p e r i m e n t s . Stimuli, apparatus, p r o c e d u r e . The p r o c e d u r e and a p p a r a t u s were t h e same a s i n t h e RT t a s k o f S t u d y 1 w i t h t h e following modifications. The t a r g e t l e t t e r p r e s e n t e d a t t h e b e g i n n i n g of e a c h t r i a l was d i s p l a y e d i n b o t h i t s u p p e r c a s e and l o w e r c a s e f o r m s t o remind t h e s u b j e c t t h a t e i t h e r form m i g h t be T h e s e two l e t t e r s were shown present in the s t i m u l u s display. f o r 500 msec f o l l o w e d by a 1 s e c b l a n k i n t e r v a l and w e r e c e n t e r e d a t what would be s e r i a l p o s i t i o n s 3 and 4 i n t h e s t i m u l u s d i s p l a y . The l e t t e r s t r i n g was t h e n d i s p l a y e d u n t i l t h e s u b j e c t responded. For a randomly s e l e c t e d o n e - h a l f of a l l t r i a l s , t h e f i r s t t h r e e l e t t e r s of t h e s t i m u l u s s t r i n g were p r e s e n t e d i n u p p e r c a s e and t h e l a s t t h r e e l e t t e r s i n l o w e r c a s e . For t h e r e m a i n i n g t r i a l s t h i s o r d e r of c a s e s was r e v e r s e d . A s i n t h e p r e v i o u s e x p e r i m e n t s , t h e s u b j e c t s s e r v e d i n two 1-hour s e s s i o n s on c o n s e c u t i v e d a y s . Each s e s s i o n c o n s i s t e d of 1 0 "yes-no" warm-up t r i a l s , 240 p r a c t i c e t r i a l s , and 400 e x p e r i m e n t a l t r i a l s . The instructions to the subjects e m p h a s i z e d s p e e d and a c c u r a c y o f r e s p o n d i n g and e n c o u r a g e d s u b j e c t s t o t r y t o " r e a d " e a c h d i s p l a y a s a whole a s t h e most e f f e c t i v e means of making f a s t and a c c u r a t e j u d g m e n t s ( J o h n s t o n & McClelland, 1 9 7 4 ) . Results

Orthographic s t r u c t u r e . The s u b j e c t s ' mean RTs f o r t h e 10 c o m b i n a t i o n s o f t y p e of t r i a l ( t a r g e t and c a t c h ) and d i s p l a y type (word, r e g u l a r - h i g h , regular-low, irregular-high, and irregular-low) were a n a l y z e d . I n c o r r e c t t r i a l RTs and c o r r e c t t r i a l R T s e x c e e d i n g 2 sec were e x c l u d e d . The e r r o r r a t e s v a r i e d between 1 . 0 % and 8 . 9 % . To d e t e r m i n e i f t h i s v a r i a b i l i t y i n

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e r r o r r a t e was a f f e c t i n g RT t r e n d s , t h e s u b j e c t s were r a n k e d on e r r o r r a t e and d i v i d e d i n t o two g r o u p s ; t h e n i n e s u b j e c t s w i t h t h e l o w e s t e r r o r r a t e s formed one g r o u p and t h e r e m a i n i n g subjects the other. The a v e r a g e RT f o r t h e s u b j e c t s w i t h l o w e r e r r o r r a t e s was 647 msec, w h e r e a s f o r t h e h i g h e r e r r o r r a t e s u b j e c t s , t h e mean RT was 756 msec, E (1, 16) = 3.47, p < .078. Grouping d i d n o t i n t e r a c t w i t h a n y o t h e r f a c t o r i n t h e analysis. The s i g n i f i c a n t main e f f e c t f o r d i s p l a y t y p e , E ( 4 , 6 4 ) = 6 5 . 2 3 , p < .001, was a n a l y z e d i n t e r m s o f t h e same c o m p a r i s o n s examined i n t h e p r e v i o u s e x p e r i m e n t s . The 7 msec d i f f e r e n c e between words and r e g u l a r - h i g h pseudowords was n o t s i g n i f i c a n t , -F < 1. The c o m p a r i s o n s among t h e anagrams r e v e a l e d t h a t t h e 30 msec d i f f e r e n c e b e t w e e n r e g u l a r and i r r e g u l a r a n a g r a m s was significant, ( 1, 6 4 ) = 3 3 . 5 0 , < .001. A l s o t h e 1 4 msec d i f f e r e n c e between h i g h and low p o s i t i o n a l - f r e q u e n c y items was < .006. The i n t e r a c t i o n o f s i g n i f i c a n t , E (1, 6 4 ) = 8 . 0 9 , r e g u l a r i t y w i t h p o s i t i o n a l f r e q u e n c y was n o t s i g n i f i c a n t , E < 1. An a n a l y s i s o f v a r i a n c e was c a l c u l a t e d on e r r o r r a t e s . T h e d i s p l a y t y p e main e f f e c t , E ( 4 , 6 8 ) = 2 . 8 6 , p < . 0 3 0 , and t h e i n t e r a c t i o n of d i s p l a y type w i t h t r i a l ( t a r g e t versus catch), E (4,68) = 2.98, p < .025, were both seem t o be s i g n i f i c a n t . Although t h e t r e n d does not p a r t i c u l a r l y m e a n i n g f u l , t h e s o u r c e o f t h e s e two e f f e c t s i s t h e somewhat g r e a t e r e r r o r r a t e f o r t h e i r r e g u l a r i t e m s o n t a r g e t trials. S i m i l a r i t y a n a l y s e s . A r e s t r i c t e d s i m i l a r i t y a n a l y s i s was done on only the lowercase letters in the display strings. R e a c t i o n times i n c r e a s e d 2 4 msec on c a t c h t r i a l s and d i d n o t c h a n g e on t a r g e t t r i a l s w i t h i n c r e a s e s from z e r o t o one s i m i l a r l e t t e r s , E (1, 1 7 ) = 5 . 8 4 , p < .05. T a r g e t v e r s u s c a t c h t r i a l s . A s i n t h e p r e v i o u s RT t a s k , t a r g e t t r i a l s were j u d g e d more q u i c k l y ( 6 6 0 msec) t h a n w e r e c a t c h t r i a l s ( 7 4 3 m s e c ) , E (1, 1 6 ) = 65.23, p < .001. Type o f t r i a l d i d n o t i n t e r a c t w i t h t y p e of l e t t e r s t r i n g . For t h e error data, catch trials (97.1%) were s i g n i f i c a n t l y more a c c u r a t e t h a n t a r g e t t r i a l s ( 9 3 . 8 % ) a s i n t h e RT d a t a o f S t u d y 1, 1 (1, 1 7 ) = 3 3 . 8 1 , p < .001. However, t r i a l t y p e d i d i n t e r a c t w i t h d i s p l a y t y p e a s noted above.

APPENDIX 4 . 4

103

Appendix 4 . 4 D e t a i l s o f Method, P r o c e d u r e , and R e s u l t s o f S t u d y 4 : L i m i t e d Viewing T i m e

Subjects. S i x t e e n I n t r o d u c t o r y Psychology s t u d e n t s , 8 m a l e s and 8 f e m a l e s , were t e s t e d f o r a s i n g l e 90-minute s e s s i o n and r e c e i v e d r e s e a r c h p a r t i c i p a t i o n c r e d i t . A s i n t h e p r e v i o u s e x p e r i m e n t s , a l l s u b j e c t s were t e s t e d f o r v i s u a l a c u i t y o f a t l e a s t 20/40, a l l r e s p o n d e d w i t h t h e i r p r e f e r r e d hand (right hand f o r 1 5 of t h e 1 6 ) , and no s u b j e c t had p a r t i c i p a t e d i n t h e e a r l i e r experiments. Procedure. The s t i m u l i and a p p a r a t u s were t h e same a s t h e p r e v i o u s e x p e r i m e n t s . An e x p e r i m e n t a l t r i a l began w i t h t h e p r e s e n t a t i o n of t h e lowercase t a r g e t l e t t e r p o s i t i o n e d w i t h i n t h e v i e w i n g r e c t a n g l e a t d i s p l a y s e r i a l p o s i t i o n 4 f o r 500 msec. A 1 sec b l a n k i n t e r v a l f o l l o w e d and t h e n t h e s t i m u l u s s t r i n g i n l o w e r c a s e was p r e s e n t e d f o r 200 msec. The s t i m u l u s was s c r o l l e d upward and r e p l a c e d by s i x u p p e r c a s e Xs which s e r v e d a s a mask and r e m a i n e d i n v i e w u n t i l t h e s u b j e c t responded. F o l l o w i n g t h e s u b j e c t ' s r e s p o n s e t h e r e was a 500 msec i n t e r t r i a l i n t e r v a l . The t e s t i n g s e s s i o n f o r e a c h s u b j e c t c o n s i s t e d of 1 0 "yes-no" warm-up t r i a l s , 240 p r a c t i c e t r i a l s , and 2 4 0 0 - t r i a l experimental sessions. A s i n a l l previous experiments, t r i a l s were g r o u p e d i n t o 80 t r i a l b l o c k s . Between b l o c k s s u b j e c t s were g i v e n a m i n u t e o r two o f r e s t and f e e d b a c k i n t h e form of a mean RT e r r o r p e r c e n t a g e f o r t h e b l o c k . A 5 m i n u t e r e s t was g i v e n between t h e two e x p e r i m e n t a l s e s s i o n s . The s u b j e c t s were t o l d t h a t h a l f t h e t r i a l s would be t a r g e t t r i a l s and h a l f would be c a t c h t r i a l s . They were a l s o i n f o r m e d t h a t t h e s t i m u l u s d i s p l a y would be b r i e f and t h a t t h e y would h a v e t o r e a d i t c a r e f u l l y . Speed and a c c u r a c y o f r e s p o n d i n g were e m p h a s i z e d .

O r t h o g r a p h i c s t r u c t u r e . A s i n t h e p r e v i o u s RT s t u d i e s , t h e s u b j e c t s ' mean RT f o r e a c h c e l l o f t h e d e s i g n , e x c l u d i n g i n c o r r e c t t r i a l RTs and c o r r e c t RTs e x c e e d i n g 2 s e c , were a n a l y z e d . The s u b j e c t s ' e r r o r r a t e s v a r i e d between 4.5% and 1 1 . 9 % , which i s h i g h e r t h a n n o r m a l l y d e s i r e d f o r RT t a s k s . For

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t h i s r e a s o n , s u b j e c t s were a g a i n r a n k e d b y e r r o r r a t e an d divided i n t o lo w a n d h i g h e r r o r r a t e g r o u p s . An a n a l y s i s o f v a r i a n c e i n d i c a t e d no e f f e c t o f g r o u p i n g t h e s u b j e c t s by e r r o r r a t e ( a l l F s < 1 ) . T h e a n a l y s e s o f t h e RT d a t a i n d i c a t e d no Only t h e d i s p l a y e f f e c t of d i s p l a y t y p e , E ( 4 , 56) = 1.27. t y p e b y t r i a l t y p e i n t e r a c t i o n was s i g n i f i c a n t . The n a t u r e o f t h i s i n t e r a c t i o n may b e s e e n i n F i g u r e 4 .1 6 . T a r g e t an d c a t c h RTs a p p e a r t o t r a d e - o f f a c r o s s d i s p l a y t y p e s . This p a t t e r n is i n d i c a t i v e of a s h i f t i n b i a s , o r a t l e a s t confidence, across A s s u b j e c t s become m o r e r e l u c t a n t ( s l o w e r ) the d i s p l a y types. t o r e s p o n d " y e s " t h e y become m o r e w i l l i n g ( f a s t e r ) t o r e s p o n d "no." For t h e most p a r t , t h i s p a t t e r n o f d e c r e a s i n g c o n f i d e n c e c o i n c i d e s w i t h t h e d e c l i n e i n o r t h o g r a p h i c s t r u c t u r e w h i c h is a r e a s o n a b l e r e a c t i o n t o d i s p l a y s t h a t a r e more d i f f i c u l t t o resolve. An a n a l y s i s o f t h e e r r o r d a t a r e v e a l e d o n l y a m a i n e f f e c t This display type o f d i s p l a y t y p e , E ( 4 , 6 0 ) = 6 . 7 9 , E < .001. Th e m ai n e f f e c t was e x a m in e d w i t h t h e u s u a l s e t o f c o n t r a s t s . d i f f e r e n c e i n e r r o r r a t e b e t w e e n w o r d s an d r e g u l a r - h i g h items was t o o s m a l l t o b e s i g n i f i c a n t , b u t t h e 1.8% d i f f e r e n c e b e t w e e n w o r d s and t h e a v e r a g e o f t h e r e g u l a r items was The e r r o r r a t e was significant, (1.60) = 6.42, p < -013. 1. 7 % s m a l l e r f o r r e g u l a r t h a n i r r e g u l a r items, (1,60) = 8.59, E < .005. N e i t h e r t h e p o s i t i o n a l - f r e q u e n c y e f f e c t ( e r r o r r a t e d i f f e r e n c e of o n l y 0.4%, 1 < 1) nor t h e i n t e r a c t i o n of r e g u l a r i t y w i t h t h e p o s i t i o n a l f r e q u e n c y were s i g n i f i c a n t , (1, 6 0 ) = 1 . 3 0 . Similarity analyses. F o r r e s p o n s e a c c u r a c y , t h e number o f s i m i l a r n o n t a r g e t l e t t e r s had no e f f e c t o n e i t h e r t a r g e t o r c a t c h t r i a l s , 2 ' s > .1. F o r RTs, t h e e f f e c t o f t h e number o f s i m i l a r n o n t a r g e t l e t t e r s had no e f f e c t o n t a r g e t t r i a l s an d a RTs l a r g e e f f e c t o n c a t c h t r i a l s , 1 ( 3 , 4 5 ) = 1 4 . 2 4 , E < .0 0 1 . i n c r e a s e d o n l y 1 msec o n t a r g e t t r i a l s an d 67 msec o n c a t c h t r i a l s w i t h i n c r e a s e s from z e r o t o t h r e e s i m i l a r l e t t e r s . Target-catch differences. A s i n t h e p r e v i o u s p o s t c u e RT e x p e r i m e n t s t h e r e was a m a i n e f f e c t o f t r i a l t y p e , E (1, 1 4 ) = 2 6 . 6 2 , E < . 0 0 1 , w i t h t a r g e t t r i a l s ( 5 6 3 msec) b e i n g r e s p o n d e d t o more q u i c k l y t h a n c a t c h t r i a l s ( 6 3 5 msec). T h e r e was a l s o the i n t e r a c t i o n of t r i a l type with d i s p l a y type discussed a b o v e. F o r t h e e r r o r d a t a , t h e r e was n e i t h e r a s i g n i f i c a n t m ai n e f f e c t o f t r i a l t y p e , E (1, 1 5 ) = 1 . 9 5 , n o r a s i g n i f i c a n t i n t e r a c t i o n w i t h d i s p l a y t y p e , E < 1.

APPENDIX 4 . 5

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Appendix 4.5 D e t a i l s of Method, P r o c e d u r e , and R e s u l t s o f S t u d y 5: Speeded RT Task w i t h Good V i s u a l I n f o r m a t i o n

Method Subjects. Eleven I n t r o d u c t o r y Psychology s t u d e n t s , 10 f e m a l e and 1 m a l e , were t e s t e d f o r a s i n g l e 1-hour s e s s i o n and received research participation credit. S u b j e c t s were t e s t e d i n f o u r g r o u p s ; t h r e e g r o u p s w i t h t h r e e p a r t i c i p a n t s and o n e w i t h two. A l l s u b j e c t s r e s p o n d e d w i t h t h e i r p r e f e r r e d hand in ( r i g h t hand f o r 9 of t h e 11). No s u b j e c t had p a r t i c i p a t e d an e a r l i e r e x p e r i m e n t . A p p a r a t u s 4 s t i m u l i . The s t i m u l i were t h e same a s i n t h e p r e v i o u s e x p e r i m e n t s . The v i s u a l d i s p l a y s were g e n e r a t e d by a DEC LSI-11 computer under s o f t w a r e c o n t r o l and p r e s e n t e d & on T e k t r o n i x Monitor 604 o s c i l l o s c o p e s ( T a y l o r , K l i t z k e , MaSSaKO, 1 9 7 8 ) . T h e s e m o n i t o r s employ a P31 phosphor w i t h a d e c a y t o . l % o f s t i m u l a t e d l u m i n a n c e w i t h i n 3 2 msec. The a l p h a b e t c o n s i s t e d of l o w e r c a s e n o n s e r i f e d l e t t e r s r e s e m b l i n g t h e t y p e f o n t U n i v e r s 55. For a n o b s e r v e r s e a t e d c o m f o r t a b l y a t an experimental s t a t i o n , t h e s i x - l e t t e r d i s p l a y s subtended a b o u t 1 . 9 d e g r e e o f v i s u a l a n g l e h o r i z o n t a l l y and t h e d i s t a n c e from t h e t o p o f a n a s c e n d e r t o t h e b o t t o m o f a d e s c e n d e r was degree. This computerized laboratory f a c i l i t y about .4 p e r m i t t e d t h e t e s t i n g of up t o f o u r s u b j e c t s i n p a r a l l e l . Each s u b j e c t r e c e i v e d t h e same v i s u a l d i s p l a y on h i s o r h e r d i s p l a y m o n i t o r , and t h e computer collected individual s u b j e c t ' s responses. Procedure. The experimental procedure was a response-signal method ( R e e d , 1 9 7 3 ) i n which t h e s u b j e c t e n d e a v o r s t o respond i n synchrony w i t h a s i g n a l which, i n t h i s c a s e , was t h e o f f s e t of t h e s t i m u l u s d i s p l a y s t r i n g . The e x a c t p r o c e d u r e was a s f o l l o w s . A t r i a l began w i t h t h e p r e s e n t a t i o n o f a s i n g l e f i x a t i o n p o i n t i n t h e c e n t e r of t h e s c r e e n . After 250 msec t h e f i x a t i o n p o i n t was r e p l a c e d by t h e t e s t l e t t e r f o r 500 msec. The f i x a t i o n p o i n t r e t u r n e d f o r 250 msec f o l l o w e d by t h e d i s p l a y s t r i n g . The d i s p l a y was i n i t i a l l y p r e s e n t e d f o r 550 msec w i t h t h i s v a l u e r e v i s e d e v e r y 2 0 t h t r i a l t o a c h i e v e a n o v e r a l l a c c u r a c y o f 75% f o r t h e g r o u p o f s u b j e c t s b e i n g t e s t e d . The t r i a l t e r m i n a t e d when a l l s u b j e c t s r e s p o n d e d o r , in the e v e n t t h a t a s u b j e c t f a i l e d t o r e s p o n d , a t t h e end of 4 s e c . A 500 msec i n t e r t r i a l i n t e r v a l was g i v e n . A t t h e end o f e v e r y 20

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t r i a l s , e a c h s u b j e c t was g i v e n f e e d b a c k a b o u t h i s o r h e r A t t r i a l termination the p e r f o r m a n c e i n t h e f o l l o w i n g manne'r. word FEEDBACK was p r e s e n t e d a t t h e c e n t e r o f t h e s c r e e n f o r 1 sec. One-half second l a t e r two columns o f numbers a p p e a r e d on t h e s c r e e n , a s u b j e c t number and t h e s u b j e c t ' s a v e r a g e d e v i a t i o n from t h e d i s p l a y s t r i n g o f f s e t t o t h e r e s p o n s e i n msec. A n e g a t i v e d e v i a t i o n i n d i c a t e d a n a v e r a g e r e s p o n s e p r i o r t o the display offset: a positive deviation indicated t h a t the a v e r a g e r e s p o n s e f e l l a f t e r t h e d i s p l a y o f f s e t . Each s u b j e c t ' s number was C l e a r l y p o s t e d a t h i s o r h e r s u b j e c t s t a t i o n t o was facilitate remembering which feedback score a p p r o p r i a t e . The f e e d b a c k s c o r e s were v i s i b l e f o r 2.5 s e c a f t e r which came the normal half second intertrial i n t e r v a l . The s u b j e c t s ' i n s t r u c t i o n s a c q u a i n t e d them w i t h t h e t a s k and t h e g e n e r a l t y p e s o f s t i m u l u s i t e m s . I t was s t r e s s e d t h a t t h e s u b j e c t s were t o be a s a c c u r a t e a s p o s s i b l e and y e t respond a s nearly in synchrony with the signal as possible. They were t o l d how t h e y would r e c e i v e f e e d b a c k and a g a i n i t was s t r e s s e d t h a t t h e y s h o u l d e n d e a v o r t o m a i n t a i n a z e r o f e e d b a c k s c o r e . A l l s u b j e c t s r e c e i v e d 120 p r a c t i c e t r i a l s f o l l o w e d by two e x p e r i m e n t a l s e s s i o n s o f 400 t r i a l s each. A s h o r t r e s t b r e a k was g i v e n between t h e two e x p e r i m e n t a l sessions. All s u b j e c t s became a d e p t a t t h e t a s k by t h e end o f t h e p r a c t i c e t r i a l s or e a r l y i n the f i r s t experimental s e s s i o n so t h a t t h e d i s p l a y o f f s e t t i m e s were r e a s o n a b l y s t a b l e t h r o u g h o u t t h e two s e s s i o n s . Average d i s p l a y o f f s e t times f o r t h e f o u r g r o u p s o f s u b j e c t s were a s f o l l o w s : 4 1 2 , 634, 485, and 505 msec.

Results S e p a r a t e a n a l y s e s were made of t h e mean a c c u r a c i e s and t h e mean R T s f o r b o t h c o r r e c t and i n c o r r e c t t r i a l s . For t h e a c c u r a c y d a t a t h e r e were n o s i g n i f i c a n t e f f e c t s ( a l l Fs < 1 ) . The a n a l y s i s o f v a r i a n c e f o r t h e R T s i n c l u d e d t r i a l t y p e , d i s p l a y c o n d i t i o n , and c o r r e c t n e s s o f t h e r e s p o n s e a s f a c t o r s . (1, 10) = T h e r e were s i g n i f i c a n t e f f e c t s of t y p e o f t r i a l , 8.04, < .017; c o r r e c t n e s s of r e s p o n s e , (1, 1 0 ) = 1 9 . 9 9 , < .001; and t h e i n t e r a c t i o n of t h e s e two f a c t o r s , (1, 1 0 34.32, < .001. T h e s e e f f e c t s w e r e a r e s u l t of t h e s i g n i f i c a n t l y s l o w e r c o r r e c t c a t c h t r i a l r e s p o n s e s seen i n F i g u r e 4.17. A l t h o u g h we o b s e r v e d t h e normal RT a d v a n t a g e f o r c o r r e c t t a r g e t t r i a l s over c o r r e c t c a t c h t r i a l s , t h e incor e c t t a r g e t and i n c o r r e c t c a t c h t r i a l s n e a r l y c o i n c i d e d w i t h t h e

r

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correct type, display ( 4 , 40) from 477

107

t a r g e t t r i a l responses. The main e f f e c t o f d i s p l a y ( 4 , 40) = 3 . 1 7 , p < . 0 2 3 , and t h e i n t e r a c t i o n of t y p e w i t h c o r r e c t n e s s o f r e s p o n s e and t y p e of t r i a l , = 3.25, < . 0 2 1 , were s i g n i f i c a n t . Mean RT i n c r e a s e d msec f o r words t o 492 msec f o r i r r e g u l a r - l o w nonwords.

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Appendix 4.6 D e t a i l s o f Method, P r o c e d u r e , and R e s u l t s of S t u d y 6: Speeded RT T a s k w i t h Poor V i s u a l I n f o r m a t i o n Method Subjects. Thirteen Introductory Psychology student v o l u n t e e r s p a r t i c i p a t e d a s s u b j e c t s ; t h e d a t a o f two w e r e l o s t due t o a computer m a l f u n c t i o n . All s u b j e c t s were n a t i v e E n g l i s h s p e a k e r s , had normal o r c o r r e c t e d - t o - n o r m a l v i s i o n , had not participated i n any o f t h e o t h e r e x p e r i m e n t s , were right-handed, and r e c e i v e d some c r e d i t t o w a r d t h e i r c o u r s e grade for p a r t i c i p a t i n g . Materials, apparatus, procedure. The s t i m u l i and in a p p a r a t u s were t h e same a s i n S t u d y 5 and a r e d e s c r i b e d Appendix 4.5. The i m p o r t a n t difference in the present e x p e r i m e n t i s t h a t t h e c o m p l e t e t e s t l e t t e r s t r i n g was r o t a t e d 180 d e g r e e s i n t h e p i c t u r e p l a n e . Rotating t h e complete t e s t s t r i n g r a t h e r than t h e individual l e t t e r s s e p a r a t e l y c r e a t e s a d i s p l a y much e a s i e r t o r e a d ( K o l e r s , 1 9 7 0 ) . The i n i t i a l d i s p l a y d u r a t i o n was l e n g t h e n e d t o 700 msec. The t a r g e t l e t t e r was s t i l l p r e s e n t e d u p r i g h t . S u b j e c t s responded " y e s " w i t h t h e i r d o m i n a n t hand.

Results The means among l e t t e r - s t r i n g t y p e s i n d i c a t e d a 1.1% a d v a n t a g e o f words o v e r t h e b e s t pseudowords ( r e g u l a r - h i g h ) and a 1 . 6 % a d v a n t a g e of words o v e r a l l t y p e s o f nonwords. Accuracy f o r r e g u l a r nonwords was 0.2% b e t t e r t h a n f o r i r r e g u l a r nonwords. Nonwords o f h i g h p o s i t i o n a l f r e q u e n c y had a 0 . 5 % a d v a n t a g e o v e r nonwords o f low p o s i t i o n a l f r e q u e n c y . A s m i g h t b e e x p e c t e d from d i f f e r e n c e s t h i s s m a l l , t h e a n a l y s i s o f v a r i a n c e i n d i c a t e d no e f f e c t of l e t t e r - s t r i n g types, E < 1. F u r t h e r m o r e , t h e r e was n o d i f f e r e n c e between t a r g e t and < 1. c a t c h t r i a l s , E < 1, and no i n t e r a c t i o n , The a c c u r a c y r e s u l t s o f t h e p r e s e n t e x p e r i m e n t c a n be compared t o t h o s e o f S t u d y 5 w i t h u p r i g h t l e t t e r s t r i n g s . This a n a l y s i s i n d i c a t e d no d i f f e r e n c e s o f any k i n d between t h e two (1, 2 1 ) = 0.14; for experiments ( f o r upright-rotated, target-catch, (1, 2 1 ) = 1 . 1 8 ; f o r t h e u p r i g h t - r o t a t e d x target-catch i n t e r a c t i o n , 1 (1, 21) = 0.07; for the l e t t e r - s t r i n g t y p e s , E ( 4 , 84) = 0.92; f o r t h e u p r i g h t - r o t a t e d x letter-string interaction, (4, 84) = 0.09; for the

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109

target-catch x l e t t e r - s t r i n g i n t e r a c t i o n , 1 ( 4 , 8 4 ) = 1.27; and f o r t h e three-way i n t e r a c t i o n , ( 4 , 84) = 0.23). An e x a m i n a t i o n o f t h e r e a c t i o n t i m e s i n t h e r o t a t e d experiment revealed r e s u l t s s i m i l a r t o those of t h e accuracy data. Means were c a l c u l a t e d o n c o r r e c t r e a c t i o n t i m e s t h a t d i d Words were a c t u a l l y n o t e x c e e d 2 , 0 0 0 msec ( 0 . 2 5 % e x c e e d e d ) . slower than regular-high nonwords. r e s p o n d e d t o 9 msec R e a c t i o n t i m e s were 9 msec l o n g e r f o r i r r e g u l a r n o n w o r d s t h a n low f o r r e g u l a r n o n w o r d s a n d 8 msec l o n g e r f o r n o n w o r d s o f r a t h e r than of high p o s i t i o n a l frequency. The a n a l y s i s o f v a r i a n c e i n d i c a t e d s i g n i f i c a n t l y l o n g e r r e a c t i o n times f o r c a t c h t r i a l s a s compared t o t a r g e t t r i a l s , -F (1, 11) = 4 6 . 7 3 , p < - 0 0 1 , b u t no e f f e c t o f 1e t t e r - s t r i ng t y p e s , 2 ( 4 , 4 4 ) = 2 . 4 3 , p < . 0 5 , a n d no i n t e r a c t o n , 1 ( 4 , 4 4 ) = 1 . 6 0 , p < .l. The r e a c t i o n times f o r t h e r o t a t e d l e t t e r s t r i n g s a l s o were c o m p a r e d t o t h o s e f o r t h e u p r i g h t l e t t e r s t r i n g s . The a v e r a g e r e a c t i o n t i m e f o r r o t a t e d l e t t e r s t r i n g s was 1 0 4 msec l o n g e r t h a n f o r u p r i g h t l e t t e r s t r i n g s , F (1, 2 1 = 2 6 . 9 4 , p < .001. C a t c h t r i a l s t o o k 66 msec l o n g e r t h a n t a r g e t t r i a l s , 1 (1, 2 1 ) = 7 5 . 8 4 , p < . 0 0 1 , b u t t h i s d i d n o t i n t e r a c t w i t h rotated, (1, 2 1 ) = w h e t h e r t h e l e t t e r s t r i n g s were 1.26. T h e r e was a n o v e r a l l d i f f e r e n c e o f l e t t e r - s t r i n g t y p e s , F (4, 8 4 ) = 5 . 7 7 , p < .001. Letter-string types did not interact with the other factors: with rotation, (4, 84) = 0.49; w i t h t a r g e t - c a t c h t r i a l s , 1 ( 4 , 84) = 1.18; and f o r t h e three-way i n t e r a c t i o n , E ( 4 , 84) = 1.18. To e x a m i n e d i f f e r e n c e s among display durations, the d i s p l a y d u r a t i o n s f o r e a c h o f t h e 40 s e t s o f 20 t r i a l s were grouped i n t o 4 b l o c k s o f 10 s e t s each. Each o f t h e c o n s e c u t i v e 4 blocks t h u s represented 10 d i s p l a y d u r a t i o n s f o r 10 sets of 20 t r i a l s . An a n a l y s i s o f v a r i a n c e i n d i c a t e d no d i f f e r e n c e s among b l o c k s , ( 3 , 33) = 0.67, b u t d i d i n d i c a t e a d i f f e r e n c e among t h e 1 0 s e t s w i t h i n a b l o c k , E ( 9 , 9 9 ) = 4 . 2 5 , 2 < . 0 0 1 , and a b l o c k b y s e t i n t e r a c t i o n , E ( 2 7 , 2 9 7 ) = 2 . 2 1 , E < . 0 0 5 . T h e s e e f f e c t s r e f l e c t t h e o p e r a t i o n o f b o t h p r a c t i c e and fatigue. Initially the display durations decreased with e x p e r i e n c e , b u t t h e n i n c r e a s e d t o w a r d t h e end o f t h e f i r s t 200 trials. Following a break between h a l v e s of t h e experiment, d i s p l a y times a g a i n decreased u n t i l l a t e i n t h e second h a l f o f t h e experiment.

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The d i s p l a y d u r a t i o n s a l s o were compared between t h e u p r i g h t and r o t a t e d e x p e r i m e n t s . A l t h o u g h t h e a v e r a g e d i s p l a y d u r a t i o n was 498 msec f o r u p r i g h t p r e s e n t a t i o n and 556 msec f o r r o t a t e d p r e s e n t a t i o n , t h e e f f e c t was n o t s i g n i f i c a n t , (1, 2 1 ) = 2.64, n o r was t h e r e a n e f f e c t o f t h e b l o c k s of 1 0 d i s p l a y d u r a t i o n s , E ( 3 , 6 3 ) = 1 . 5 6 , and t h e two f a c t o r s a l s o d i d n o t T h e r e w e r e , however, d i f f e r e n c e s i n t e r a c t , E ( 3 , 6 3 ) = 2.53. among i n d i v i d u a l d i s p l a y d u r a t i o n s , ( 9 , 189) = 2.05, E < .05, and d i s p l a y d u r a t i o n s i n t e r a c t e d w i t h e v e r y t h i n g e l s e : w i t h upright-rotated l e t t e r s t r i n g s , E ( 9 , 1 8 9 ) = 4.65, E < . 0 0 1 ; w i t h b l o c k s , F ( 2 7 , 567) = 1 . 6 3 , p < . 0 5 ; and i n a t h r e e - w a y interaction, ( 2 7 , 567) = 1 . 6 9 , E < .05. These i n t e r a c t i o n s r e f l e c t t h e s l i g h t f a t i g u e f a c t o r in t h e r o t a t e d e x p e r i m e n t and t h e a b s e n c e o f s u c h i n t h e u p r i g h t e x p e r i m e n t . For t h e u p r i g h t s t i m u l i , t h e d i s p l a y d u r a t i o n s continued t o decrease throughout the experiment.

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111

Appendix 4.7 D e t a i l s o f Method, P r o c e d u r e , and R e s u l t s o f S t u d y 7: High-Accuracy RT Task w i t h Poor V i s u a l I n f o r m a t i o n

Twelve s u b j e c t s were used and met t h e same c o n s t r a i n t s a s The same i n t h e s p e e d e d RT t a s k i n S t u d y 6 (Appendix 4 . 6 ) . r o t a t e d s t i m u l i a l s o were used w i t h t h e f o l l o w i n g p r o c e d u r a l d i f f e r e n c e s . A t r i a l c o n s i s t e d o f a 250 msec f i x a t i o n p o i n t f o l l o w e d by a n u p r i g h t l e t t e r which was p r e s e n t e d f o r 5 0 0 msec a t t h e f i x a t i o n p o i n t and t h e n t h e r o t a t e d l e t t e r s t r i n g . The l e t t e r s t r i n g remained on t h e s c r e e n u n t i l t h e l a s t s u b j e c t ( u p t o f o u r a t a time) r e s p o n d e d . Results Means were c a l c u l a t e d f o r c o r r e c t r e a c t i o n times t h a t d i d msec (1.4% e x c e e d e d ) . R e a c t i o n times n o t e x c e e d 2,000 g e n e r a l l y i n c r e a s e d from words t o t h e i r r e g u l a r - l o w nonwords, F ( 4 , 4 4 ) = 6 . 4 7 , E < .081. R e g u l a r - h i g h nonwords a v e r a g e d 6 msec l o n g e r t h a n w o r d s , i r r e g u l a r nonwords r e s u l t e d i n r e a c t i o n times t h a t were 1 6 msec l o n g e r t h a n r e g u l a r nonwords, and nonwords o f low p o s i t i o n a l f r e q u e n c y r e s u l t e d i n r e a c t i o n times t h a t were 18 msec l o n g e r t h a t nonwords of h i g h p o s i t i o n a l f r e q u e n c y . The a v e r a g e r e a c t i o n times f o r c a t c h t r i a l s was 110 msec l o n g e r t h a n f o r t a r g e t t r i a l s , F (1, 11) = 1610.10, p < .001, b u t t h i s d i d n o t i n t e r a c t w i t h l e t t e r - s t r i n g t y p e s , 1 ( 4 , 4 4 ) = 0.79.

D i f f e r e n c e s between l e t t e r s t r i n g s were f u r t h e r examined by o r t h o g o n a l c o n t r a s t s . The d i f f e r e n c e between words and a l l nonwords was s i g n i f i c a n t , t ( 4 4 ) = 3 . 1 8 , p < .005, a s was t h e d i f f e r e n c e between r e g u l a r and i r r e g u l a r nonwords, t ( 4 4 ) = 1.683, p = .05. However, t h e d i f f e r e n c e between nonwords o f h i g h and low p o s i t i o n a l f r e q u e n c y was n o t s i g n i f i c a n t , t ( 4 4 ) = 0.94. S i m i l a r l y , a Newman-Kuels t e s t i n d i c a t e d t h a t t h e 6 msec difference between words and the best pseudowords ( r e g u l a r - h i g h ) was n o t s i g n i f i c a n t , p > .10. A c o m p a r i s o n of r e a c t i o n times between t h e i n i t i a l r e p l i c a t i o n e x p e r i m e n t u s i n g u p r i g h t s t i m u l i and t h e p r e s e n t times f o r r o t a t e d s t i m u l i study indicated t h a t reaction a v e r a g e d 2 7 9 msec l o n g e r t h a n f o r u p r i g h t s t i m u l i , (1, 2 4 ) = 42.35, 2 < .0Ol. The d i f f e r e n c e between c a t c h and t a r g e t

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was s i g n i f i c a n t , F (1, 24) = 1 5 3 . 4 4 , p < . 0 0 1 , a s was the t r i a l type x rotated-upright interaction, (1, 2 4 ) = 23 . 6 8 , 2 < - 0 0 1 . D i f f e r e n c e s b e t w e e n l e t t e r s t r i n g s were s i g n i f i c a n t , E ( 4 , 9 6 ) = 20.12, 2 < .001, b u t l e t t e r s t r i n g s d i d not i n t e r a c t with anything: with rotated-upright, ( 4 , 96) = 0.53; with target-catch, E ( 4 , 96) = 0.53; and f o r t h e three-way i n t e r a c t i o n , ( 4 , 9 6 ) = 1.60.

trials

APPENDIX 4.8

113

Appendix 4.8 D e t a i l s o f Method, P r o c e d u r e , and R e s u l t s o f S t u d y 8 : T y p i c a l i t y Ratings

The subjects

o v e r t judgment experiments c o n s i s t e d of a s k i n g to make conscious judgments about the test items. T h r e e s e t s o f r a t i n g j u d g m e n t s were o b t a i n e d u n d e r s i m i l a r i n s t r u c t i o n s and a r e d e s c r i b e d h e r e a s " T y p i c a l i t y Ratings." A f o u r t h r a t i n g was o b t a i n e d i n S t u d y 9 u n d e r e x p l i c i t i n s t r u c t i o n s a s t o t h e n a t u r e of p o s i t i o n a l f r e q u e n c y and is d e s c r i b e d a s " P o s i t i o n a l - F r e q u e n c y R a t i n g s . " A f i n a l s e t o f j u d g m e n t s i n S t u d y 1 0 were o b t a i n e d by a " P a i r e d - J u d g m e n t " procedure. Method R a t i n g Forms. T h r e e r a t i n g f o r m s were p r e p a r e d . The f i r s t form employed t h e 1 6 0 a n a g r a m s ; t h e s e c o n d form employed t h e 1 6 0 anagrams p l u s 40 pseudowords d e r i v e d from t h e o r i g i n a l words by t h e s u b s t i t u t i o n of a s i n g l e l e t t e r ; and t h e t h i r d form used t h e e n t i r e 200 s t i m u l u s s t r i n g s i n c l u d i n g t h e o r i g i n a l words. ( S e e Appendix 4 . 1 8 f o r t h e 40 words and t h e i r 160 a n a g r a m s ; see Appendix 4.8A f o r t h e o n e - l e t t e r s u b s t i t u t i o n p s e u d o w o r d s ) . Each l i s t was randomized and p r i n t e d w i t h 20 l e t t e r s t r i n g s p e r p a g e . The s t r i n g s were t y p e d i n l o w e r c a s e w i t h f i v e u n d e r s c o r e s t y p e d t o t h e r i g h t of e a c h s t r i n g a s a space f o r w r i t i n g t h e s t r i n g ' s r a t i n g . The r a t i n g s c a l e t o be used was r e p r o d u c e d a t t h e t o p o f e a c h p a g e a s f o l l o w s : "Most l i k e E n g l i s h 1 0 9 8 7 6 5 4 3 2 1 L e a s t l i k e E n g l i s h . " The f o u r or f i v e p a g e s c o m p r i s i n g e a c h l i s t were a s s e m b l e d i n random o r d e r i n t o b o o k l e t s . Each b o o k l e t was p r e p a r e d w i t h a n a p p r o p r i a t e s h e e t of i n s t r u c t i o n s . These i n s t r u c t i o n s a r e r e p r o d u c e d i n Appendix 4.8B, and 4.8C. Introductory S u b j e c t s . One hundred ninety-e ight P s y c h o l o g y s t u d e n t s f i l l e d o u t one of t h r e e r a t i n g f o r m s . The r a t e r s p a r t i c i p a t e d i n g r o u p s o f 8 t o 1 2 p e r s o n s and r e c e i v e d r e s e a r c h p a r t i c i p a t i o n c r e d i t . The f i r s t 70 s u b j e c t s r a t e d t h e f i r s t form which c o n t a i n e d o n l y t h e 1 6 0 anagrams. The n e x t 65 s u b j e c t s f i l l e d o u t t h e s e c o n d form which i n c l u d e d t h e 160 anagrams and t h e o n e - l e t t e r s u b s t i t u t i o n pseudowords made from t h e words. The f i n a l 63 s u b j e c t s r a t e d t h e t h i r d form which

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c o n t a i n e d t h e o r i g i n a l s e t o f 200 s t i m u l u s items ( i . e . , t h e 1 6 0 a n a g r a m s an d t h e 40 w o r d s ) . Each s u b j e c t worked a t h i s o r h e r own s p e e d , an d o n t h e a v e r a g e , t o o k 1 5 t o 2 5 m i n u t e s t o r a t e t h e items. -P r o cedure. Each s e s s i o n b e g a n with t h e experimenter reading t h e i n s t r u c t i o n s while the s u b j e c t followed along. The f o r m a l i n s t r u c t i o n s were s u p p l e m e n t e d w i t h v e r b a l i n s t r u c t i o n s s t r e s s i n g " s i m i l a r i t y t o English s p e l l i n g " a s the primary rating criterion. S u b j e c t s were u r g e d n o t t o a d o p t s t r a t e g i e s of r a t i n g r e g u l a r i t y on t h e b a s i s of being a b l e t o transform a s t r i n g i n t o a word through l e t t e r a d d i t i o n s , d e l e t i o n s , s u b s t i t u t i o n s , o r by m a k in g a n a g r a m s . The r a t e r s who r e c e i v e d t h e l i s t c o n t a i n i n g a c t u a l w o r d s were a l s o a s k e d t o d i s r e g a r d t h e s e m a n t i c c o n t e n t o f t h e words t o t h e f u l l e s t e x t e n t possible. F i n a l l y , t h e r e l a t i v e n a t u r e o f t h e s c a l e was stressed. I t was i n d i c a t e d t h a t t h e p s y c h o l o g i c a l s c a l e s h o u l d s p a n t h e p r e s e n t e d s e t o f i t e m s and a l l 1 0 s c a l e v a l u e s s h o u l d be used. Results A v e r a g e r a t i n g s were t a b u l a t e d b o t h w i t h i n s u b j e c t s an d across subjects. For t h e w i t h i n s u b j e c t t a b u l a t i o n s , t h e s u b j e c t ' s r a t i n g s f o r t h e 40 s t i m u l i i n e a c h c a t e g o r y were averaged. F o r t h e item a n a l y s e s , a n a v e r a g e f o r e a c h item w as o b t a i n e d by averaging the ratings assigned by each subject. These d a t a permitted a n a l y s e s t o determine i f t h e ratings' r e l i a b i l i t y r e f l e c t e d d i f f e r e n c e s i n mean r a t i n g s f o r analyses of t h e 4 o r 5 c a t e g o r i e s o f s t i m u l i . S i x one-way v a r i a n c e w e r e c o m p u te d f o r a l l p a i r w i s e c o m p a r i s o n s among t h e three instruction conditions; t h r e e a n a l y s e s were b a s e d o n s u b j e c t s a s t h e s a m p l i n g v a r i a b l e a n d t h r e e were b a s e d o n items a s t h e s a m p l i n g v a r i a b l e . The mean r a t i n g s w e r e s o r e l i a b l e t h a t e r r o r v a r i a n c e s were u n i f o r m l y s m a l l i n a l l s i x a n a l y s e s ( s t a n d a r d e r r o r o f e s t i m a t e is t h e r a n g e o f .0 4 t o .68 s c a l e u n i t s f o r a l l s i x a n a l y s e s ) . W it h s u c h s m a l l e r r o r v a r i a n c e s , a l l p a i r w i s e d i f f e r e n c e s b e t w e e n c a t e g o r y m ean s were r e l i a b l e a t t h e .05 l e v e l .

115

A P P E N D I X 4.8A

Appendix 4.8A The Pseudowords used i n S t u d y 8 .

Word action amount answer barely belong breath bridge charge double famous finger garden gather glance hardly itself 1awye r longer master modern

Pseudoword aption amaunt onswer parely belang breeth bradge churge gouble vamous vinger gurden gither glunce herdly itsolf rawyer ronger moster madern

Word mother namely nearly perm i t player poetry purely reason remain result shared s imp1 e single spread stared stream travel trials turned winter

Pseudoword mather nomely mearly permat plader boetry burely leason remoin resilt sharet sumple f ingle spreed stured streem trove1 treals tarned wunter

11 6

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A p p e n d ix 4.88 D i r e c t i o n s f o r T y p i c a l i t y R a t i n g s W i t h o u t Words an d f o r T y p i c a l i t y R a t i n g s W it h P s e u d o w o r d s

On t h e p a g e s w h i c h f o l l o w a r e l e t t e r s t r i n g s made u p t o None o f t h e s t r i n g s , h o w e v e r , i s a n look l i k e E n g l i s h words. E n g l i s h word. Your t a s k i s t o r a t e e a c h o n e o n a s c a l e o f 1 t o 1 0 a c c o r d i n g t o how much i t l o o k s l i k e a r e a l E n g l i s h word. S t r i n g s wh i ch a r e e x t r e m e l y c l o s e s h o u l d b e g i v e n h i g h r a t i n g s , w h i l e s t r i n g s which a r e n o t v e r y c l o s e s h o u l d b e g i v e n low ratings. S i n c e no r e a l w o r d s a r e included, the highest p o s s i b l e r a t i n g (10) s h o u l d b e g i v e n t o s t r i n g s w h i c h you f e e l a r e most l i k e E n g l i s h words. Similarly, a r a t i n g of 1 should b e g i v e n t o t h e s t r i n g w h i c h a r e l e a s t l i k e E n g l i s h w o r d s. The s t r i n g s have been s e l e c t e d t o r e p r e s e n t a l l p o s s i b l e l e v e l s o f s i m i l a r i t y t o E n g l i s h w i t h r o u g h l y e q u a l n u m b er s a t e a c h l e v e l . Skim o v e r t h e s t r i n g s o n t h e f i r s t p a g e b e f o r e you b e g i n There r a t i n g s o you h a v e a n i d e a o f t h e i r r a n g e o f v a r i a t i o n . a r e 160(200) s t r i n g s i n a l l , d i v i d e d r a n d o m l y a c r o s s 4 ( 5 ) pages, s o e a c h p a g e s h o u l d h a v e r o u g h l y t h e same v a r i a t i o n a s any .other. You s h o u l d work a t a f a i r l y q u i c k and e v e n p a c e a l t h o u g h t h e r e is n o t i m e l i m i t .

APPENDIX 4 . 8 C

117

Appendix 4.8C D i r e c t i o n s f o r T y p i c a l i t y R a t i n g s w i t h Words

On t h e p a g e s which f o l l o w a r e l e t t e r s t r i n g s made up t o be Some of t h e s t r i n g s a r e , i n f a c t , s p e l l e d l i k e E n g l i s h words. E n g l i s h words, whereas other strings are not English words. I n d e p e n d e n t o f t h e meaning o f t h e w o r d s , however, y o u r t a s k i s t o r a t e e a c h one o n a s c a l e of 1 t o 1 0 a c c o r d i n g t o how much i t is s p e l l e d l i k e t y p i c a l E n g l i s h s p e l l i n g . S t r i n g s which a r e e x t r e m e l y c l o s e s h o u l d be g i v e n h i g h r a t i n g s , w h i l e s t r i n g s which a r e n o t v e r y c l o s e s h o u l d be g i v e n low r a t i n g s . The h i g h e s t p o s s i b l e r a t i n g ( 1 0 ) s h o u l d be g i v e n t o s t r i n g s Similarly, a which you f e e l a r e s p e l l e d most l i k e E n g l i s h . r a t i n g o f 1 s h o u l d be g i v e n t o t h e s t r i n g s which a r e s p e l l e d The s t r i n g s h a e been s e l e c t e d t o r e p r e s e n t l e a s t l i k e English. a l l p o s s i b l e l e v e l s of s i m i l a r i t y t o En g lish s p e l l i n g w i t h r o u g h l y e q u a l numbers a t e a c h l e v e l . Skim o v e r t h e s t r i n g s on t h e f i r s t p a g e s b e f o r e you b e g i n There r a t i n g s o you h a v e a n i d e a of t h e i r r a n g e of v a r i a t i o n . so a r e 200 s t r i n g s i n a l l , d i v i d e d randomly a c r o s s 5 p a g e s , e a c h page s h o u l d h a v e r o u g h l y t h e same v a r i a t i o n a s a n y o t h e r . You s h o u l d work a t a f a i r l y q u i c k and e v e n p a c e a l t h o u g h t h e r e is no time l i m i t .

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118

Appendix 4 . 9 The Method, P r o c e d u r e , and R e s u l t s o f S t u d y 9 : Positional-Frequency Ratings

Method R a t i n g forms were c o n s t r u c t e d by g e n e r a t i n g f r e s h c o p i e s of t h e form from S t u d y 8 employing t h e 160 anagrams. Explicit p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s ( r e p r o d u c e d i n Appendix 4.9A) were s u b s t i t u t e d for t h e p r e v i o u s i n s t r u c t i o n s and t h e s c a l e a t t h e t o p o f e a c h p a g e was m o d i f i e d t o r e a d : "Most f r e q u e n t 1 0 9 8 7 6 5 4 3 2 1 L e a s t f r e q u e n t . " s u b j e c t s were t e s t e d i n small g r o u p s of 8 t o 1 0 ; t h e f o r m a l i n s t r u c t i o n s were r e a d f o l l o w e d by v e r b a l e m p h a s i s o f t h e s a l i e n t p o i n t s o f t h e i n s t r u c t i o n s ; and s u b j e c t s were g i v e n u n l i m i t e d time a l t h o u g h t h e y u s u a l l y c o m p l e t e d t h e form i n 1 5 t o 25 m i n u t e s . F o r t y - n i n e I n t r o d u c t o r y Psychology s t u d e n t s r a t e d t h i s form.

As before,

Results As i n S t u d y 8 , a v e r a g e r a t i n g s were t a b u l a t e d by l e t t e r s t r i n g t y p e f o r e a c h s u b j e c t and f o r e a c h s t i m u l u s item a c r o s s subjects. Two a n a l y s e s o f v a r i a n c e w e r e computed on t h e s e d a t a and, a s i n t h e p r e v i o u s ratings, a l l possible pairwise c o m p a r i s o n s o f t h e f o u r anagram c a t e g o r i e s were s i g n i f i c a n t .

APPENDIX 4.9A

119

Appendix 4.9A Directions f o r Positional-Frequency Ratings

It is a r e l a t i v e l y s i m p l e matter to determine t h e f r e q u e n c y w i t h which t h e d i f f e r e n t l e t t e r s of t h e a l p h a b e t a r e I t is another m a t t e r to used a t v a r i o u s l o c a t i o n s i n words. d e t e r m i n e i f p e o p l e a r e aware o f t h i s " p o s i t i o n a l f r e q u e n c y . " On t h e p a g e s which f o l l o w a r e l e t t e r s t r i n g s d e r i v e d by anagramming common E n g l i s h s i x - l e t t e r words. I n some i n s t a n c e s t h e l e t t e r s h a v e b e e n moved t o t h e p o s i t i o n s t h e y most commonly occupy i n s i x - l e t t e r words ( h i g h f r e q u e n c y p o s i t i o n s ) and i n some i n s t a n c e s t h e y h a v e been moved t o l o c a t i o n s t h a t t h e y v e r y i n f r e q u e n t l y occupy i n six-letter words (low frequency p o s i t i o n s ) . Your t a s k i s t o r a t e e a c h s t r i n g on a s c a l e o f 1 t o 1 0 a c c o r d i n g t o how much you b e l i e v e t h a t t h e l e t t e r s i n t h e s t r i n g occupy t h e i r most f r e q u e n t p o s i t i o n s . The h i g h e s t possible rating ( 1 0 ) s h o u l d b e g i v e n t o t h e s t r i n g s whose l e t t e r s a r e i n t h e i r most f r e q u e n t p o s i t i o n s . The l o w e s t rating (1) s h o u l d be g i v e n t o s t r i n g s whose l e t t e r s a r e i n their l e a s t frequent p o s i t i o n s . The strings have been c o n s t r u c t e d s o t h a t some s t r i n g s h a v e a l l t h e i r l e t t e r s i n t h e i r most f r e q u e n t p o s i t i o n s , some s t r i n g s h a v e t h e i r l e t t e r s i n t h e i r l e a s t f r e q u e n t p o s i t i o n s , and t h e r e m a i n i n g s t r i n g s have l e t t e r s a t a l l v a r i o u s p o s i t i o n s of g r e a t e r o r l e s s e r f r e q u e n c y . Thus you s h o u l d f i n d s t r i n g s a p p r o p r i a t e t o a l l 10 l e v e l s o f t h e s c a l e w i t h r o u g h l y e q u a l numbers a t e a c h l e v e l . Skim o v e r t h e s t r i n g s on t h e f i r s t page b e f o r e you b e g i n r a t i n g s o you h a v e a n i d e a o f t h e i r r a n g e of v a r i a t i o n . T h e r e a r e 160 s t r i n g s i n a l l , d i v i d e d randomly a c r o s s f o u r p a g e s , s o e a c h page s h o u l d h a v e r o u g h l y t h e same v a r i a t i o n a s a n y o t h e r . You s h o u l d work a t a f a i r l y q u i c k and e v e n p a c e e v e n t h o u g h t h e r e is no time l i m i t .

CHAPTER 4

120

Appendix 4.10 D e t a i l s o f Method, P r o c e d u r e , and R e s u l t s o f S t u d y 1 0 : R e g u l a r i t y v e r s u s Positional-Frequency Paired-Judgments

Method Response forms. The p a i r e d - j u d g m e n t f o r m s were p r e p a r e d by f i r s t p a r t i t i o n i n g e a c h o f t h e f o u r c a t e g o r i e s o f a n a g r a m s i n t o f o u r randomly s e l e c t e d s u b s e t s o f 1 0 items e a c h . E i g h t y p a i r s were p r o d u c e d by p a i r i n g t h e 1 6 0 anagrams a s f o l l o w s : One 1 0 - i t e m s u b s e t from e a c h c a t e g o r y was matched t o a 1 0 - i t e m s u b s e t from a n o t h e r c a t e g o r y and t h e members of t h e s u b s e t p a i r e d o f f p r o d u c i n g between c a t e g o r y p a i r s . T h i s l e f t one 1 0 - i t e m s u b s e t w i t h i n e a c h c a t e g o r y whose members were p a i r e d w i t h e a c h o t h e r t o form f i v e w i t h i n c a t e g o r y p a i r s . A t o t a l l i s t o f 320 p a i r s was formed by p e r f o r m i n g t h i s matching p r o c e d u r e f o u r times, r o t a t i n g t h e m a t i n g o f t h e s u b s e t s w i t h i n each c a t e g o r y t o a c h i e v e a co mp l et el y c o u n te rb a la n c e d l i s t where e v e r y i t e m was p a i r e d o n c e w i t h a member of e v e r y o t h e r c a t e g o r y and o n c e w i t h a member of i t s own c a t e g o r y . Eight such t o t a l l y d i f f e r e n t l i s t s were c o n s t r u c t e d and item b a l a n c i n g ( r i g h t - h a n d p a i r member v e r s u s l e f t - h a n d p a i r member) was randomized. The t o t a l e f f e c t was t o e n s u r e t h a t e v e r y item had a n e q u a l o p p o r t u n i t y t o be p a i r e d w i t h a n y o t h e r item. Once c o n s t r u c t e d , t h e l i s t s were p r i n t e d w i t h 80 p a i r s p e r page. Each b o o k l e t was p r e f a c e d w i t h a s e t o f i n s t r u c t i o n s which e i t h e r g a v e a d e t a i l e d d e s c r i p t i o n of r e g u l a r i t y o r p o s i t i o n a l f r e q u e n c y . I n b o t h c a s e s , a p p r o p r i a t e e x a m p l e s were i n c l u d e d . The " r e g u l a r i t y " i n s t r u c t i o n s g r o u p c h o s e t h e m o s t r e g u l a r of e a c h pair whereas t h e " p o s i t i o n a l - f r e q u e n c y ' ' i n s t r u c t i o n s g r o u p c h o s e t h e member w i t h t h e h i g h e s t p o s i t i o n a l frequency. Subjects. Forty-eight I n t r o d u c t o r y Psychology s t u d e n t s 22 completed t h e paired-judgment t a s k . Of these r a t e r s , received "regularity" instructions and 26 received All subjects received "positional-frequency" instructions. r e s e a r c h p a r t i c i p a t i o n c r e d i t a s recompense. A s in the previous rating studies, subjects Procedure. were t e s t e d i n g r o u p s o f 1 0 t o 1 5 and g i v e n u n l i m i t e d time t o t h e somewhat l e n g t h i e r f o r m , c o m p l e t e t h e form. D u e t o s u b j e c t s t o o k 20 t o 30 minutes t o c o m p l e t e t h e form. Approximately one-half of the groups received e x p l i c i t r e g u l a r i t y i n s t r u c t o n s ( s e e Appendix 4.10A) , which d e s c r i b e d

APPENDIX 4.10

121

l e t t e r s e q u e n c e r e g u l a r i t y , and r e q u i r e d t h a t t h e more r e g u l a r member of e a c h p a i r be c h o s e n . The r e m a i n i n g g r o u p s r e c e i v e d e x p l i c i t p o s i t i o n a l - f r e q u e n c y i n s t r u c t i o n s ( s e e Appendix 4 . 1 0 B ) which d e s c r i b e d s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y and r e q u i r e d t h a t t h e member of e a c h p a i r w i t h t h e h i g h e r o v e r a l l p o s i t i o n a l frequency be chosen. A l l s u b j e c t s w i t h i n a group received t h e same i n s t r u c t i o n s .

Results The p r o p o r t i o n s o f times t h a t i t e m s from a n anagram c a t e g o r y were c h o s e n o v e r items from t h e same c a t e g o r y o r d i f f e r e n t c a t e g o r i e s a r e shown i n T a b l e 4.5. Table 4.5 g i v e s t h e p r o p o r t i o n o f times an i t e m from t h e column c a t e g o r y was selected when paired with an item from the row c a t e g o r y . Comparing t h e two p a n e l s o f T a b l e 4.5 w e o b s e r v e t h a t s u b j e c t s i n b o t h i n s t r u c t e d c o n d i t i o n s made c h o i c e s more c o n s i s t e n t w i t h t h e a p p l i c a t i o n of r e g u l a r i t y t h a n w i t h t h e a p p l i c a t i o n of p o s i t i o n a l f r eq u en cy alth o u g h both observed tables differ from the hypothesized "perfect" outcome. Comparing t h e two p a n e l s of T a b l e 4 . 5 t o e a c h o t h e r , we see e v i d e n c e a g a i n t h a t s u b j e c t s c a n modify t h e i r j u d g m e n t s s l i g h t l y when g i v e n e x p l i c i t instructions t o attend t o p o s i t i o n a l frequency.

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Appendix 4.10A R e g u l a r i t y I n s t r u c t i o n s f o r Paired-Judgments

Our r e s e a r c h is d i r e c t e d a t d i s c o v e r i n g what i t i s we know a b o u t E n g l i s h words t h a t a l l o w s u s t o l o o k a t m e a n i n g l e s s s t r i n g s of l e t t e r s and j u d g e how much t h e y r e s e m b l e words. In t r y i n g t o u n d e r s t a n d t h e s t r u c t u r e p r e s e n t i n words, we h a v e f o c u s e d on a n i m p o r t a n t component p r o p e r t y - - r e g u l a r i t y of For e x a m p l e , t h e r e a r e many c o n s o n a n t l e t t e r sequencing. th, etc.) s e q u e n c e s which b e g i n words ( e . g . , @, and which end words ( e . g . , 9, e l e t c . ) . There a r e common vowel s e q u e n c e s a s w e l l ( e . g . , 00, 9 , G , sf e t c . ) . F i n a l l y , . t h e r e i s r e g u l a r i t y i n how t h e s e c o n s o n a n t s and vowel g r o u p i n g s a r e t h e m s e l v e s s e q u e n c e d w i t h i n words. On t h e p a g e s which f o l l o w a r e 320 p a i r s o f m e a n i n g l e s s six-letter s t r i n g s which h a v e been c o n s t r u c t e d t o v a r y a l o n g t h i s d i m e n s i o n of l e t t e r s e q u e n c e r e g u l a r i t y . T h a t i s , some s t r i n g s p r e s e r v e normal l e t t e r s e q u e n c i n g w h i l e o t h e r s v i o l a t e normal s e q u e n c i n g t o a l e s s e r or g r e a t e r d e g r e e . The o b j e c t o f t h i s e x p e r i m e n t is t o d e t e r m i n e t h e e x t e n t o f your knowledge by h a v i n g you s e l e c t t h e more r e g u l a r s t r i n g i n e a c h p a i r . You a r e t o e v a l u a t e b o t h members o f e a c h p a i r and c h o o s e t h e one t h a t is more p e r m i s s i b l e i n t e r m s o f r e g u l a r i t y o f l e t t e r sequencing. B e f o r e you b e g i n , s k i m o v e r t h e p a i r s o n t h e f i r s t p a g e t o g e t a f e e l f o r t h e t a s k . Once you b e g i n , t r y t o work a t a f a i r l y s t e a d y p a c e and n o t d w e l l t o o l o n g on t h e p a i r s you f i n d d i f f i c u l t . You m u s t make a c h o i c e f o r e a c h p a i r , g u e s s i n g i f necessary. Have you any q u e s t i o n s ?

=,a, *,e,

e,

APPENDIX 4.10B

123

Appendix 4.10B Positional-Frequency I n s t r u c t i o n s f o r Paired-Judgments

Our r e s e a r c h i s d i r e c t e d a t d i s c o v e r i n g what i t is we know a b o u t E n g l i s h words t h a t a l l o w s u s t o l o o k a t m e a n i n g l e s s s t r i n g s o f l e t t e r s and j u d g e how much t h e y r e s e m b l e words. In t r y i n g t o u n d e r s t a n d t h e s t r u c t u r e p r e s e n t i n words, w e have f o c u s e d on a n i m p o r t a n t component p r o p e r t y - - l e t t e r frequency. I n d i v i d u a l l e t t e r s and g r o u p s o f l e t t e r s o c c u r w i t h v a r y i n g f r e q u e n c y a t d i f f e r e n t p o s i t i o n s w i t h i n words. For e x a m p l e , you c a n p r o b a b l y t h i n k o f words t h a t end i n fi and words t h a t end i n y, b u t fi i s 1 0 t i m e s more f r e q u e n t t h a n y i n f i n a l L i k e w i s e , 9 and & b o t h o c c u r a t t h e b e g i n n i n g of position. words, b u t i s 50 times a s f r e q u e n t i n i n i t i a l p o s i t i o n . In g e n e r a l , c o n s o n a n t s a r e more f r e q u e n t t h a n vowels a t word i n i t i a l and word f i n a l p o s i t i o n s w i t h t h e e x c e p t i o n o f f i n a l e , and s o on. On t h e p a g e s which f o l l o w a r e 320 p a i r s of m e a n i n g l e s s six-letter s t r i n g s which h a v e b e e n c o n s t r u c t e d t o v a r y a l o n g t h e d i m e n s i o n of l e t t e r f r e q u e n c y by p o s i t i o n . T h a t i s , some s t r i n g s h a v e been c r e a t e d by p l a c i n g e a c h l e t t e r i n i t s m o s t f r e q u e n t p o s i t i o n i n s i x - l e t t e r E n g l i s h words. O t h e r s have t h e i r l e t t e r s p l a c e d i n l e s s f r e q u e n t p o s i t i o n s and s t i l l o t h e r s have t h e i r l e t t e r s i n t h e i r l e a s t f r e q u e n t p o s i t i o n s . The o b j e c t of t h i s e x p e r i m e n t is t o d e t e r m i n e how w e l l you can judge when letters are in their most f r e q u e n t positions. You a r e t o e v a l u a t e b o t h members o f e a c h p a i r and c h o o s e t h e more " f r e q u e n t " o f t h e two, e . g . , t h e s t r i n g which a p p e a r s t o h a v e more o f i t s l e t t e r s i n t h e i r more f r e q u e n t positions. B e f o r e you b e g i n , s k i m o v e r t h e p a i r s on t h e f i r s t p a g e t o g e t a f e e l f o r t h e t a s k . Once you b e g i n , t r y t o work a t a f a i r l y s t e a d y p a c e and n o t t o d w e l l t o o l o n g on t h e p a i r s you find d i f f i c u l t . You m u s t make a c h o i c e f o r e a c h p a i r , g u e s s i n g i f necessary. Have you any q u e s t i o n s ?


5

Structural Descriptions

To p r o v i d e a more d e t a i l e d a n a l y s i s o f o r t h o g r a p h i c s t r u c t u r e e f f e c t s , we c o n d u c t e d p o s t h o c c o r r e l a t i o n a l a n a l y s e s o f t h e p e r c e p t u a l r e c o g n i t i o n and o v e r t judgment d a t a r e p o r t e d The i n d e p e n d e n t v a r i a b l e s w e r e b a s e d upon i n Chapter 4. v a r i o u s f r e q u e n c y and r e g u l a r i t y m e a s u r e s . Even t h o u g h f i r m c o n c l u s i o n s m i g h t n o t b e r e a c h e d , we f e l t t h a t o u r s a m p l e of items was s u f f i c i e n t l y l a r g e and s u f f i c i e n t l y r e p r e s e n t a t i v e t h a t these correlational analyses could provide valid i n d i c a t i o n s o f which m e a s u r e s m i g h t w a r r a n t f u r t h e r t h e o r e t i c a l and e m p i r i c a l e x a m i n a t i o n . T h r e e d e p e n d e n t m e a s u r e s were d e r i v e d from t h e e x p e r i m e n t s r e p o r t e d i n C h a p t e r 4 f o r e a c h o f t h e 200 s t i m u l u s items, i . e . , The f i r s t m e a s u r e was t h e t h e 40 words and t h e i r 4 anagrams. mean a c c u r a c y f o r e a c h item averaged a c r o s s a l l t r i a l occurrences i n the postcue a c c u r a c y experiment of Study 1: I n i t i a l R e p l i c a t i o n and t h e p r e c u e and p o s t c u e e x p e r i m e n t s o f S t u d y 2: P r e c u e v e r s u s P o s t c u e . A c o r r e s p o n d i n g r e a c t i o n time ( R T ) m e a s u r e was d e r i v e d by a v e r a g i n g t h e RTs f o r a l l t r i a l o c c u r r e n c e s o f e a c h item i n t h e r e a c t i o n time e x p e r i m e n t s o f S t u d y 1: I n i t i a l R e p l i c a t i o n and S t u d y 3 : Mixed-Case. The t h i r d m e a s u r e was t h e a v e r a g e r a t i n g s from one of t h e r a t i n g e x p e r i m e n t s i n S t u d y 8 : T y p i c a l i t y R a t i n g s . The e x p e r i m e n t was t h e one i n which t h e words t h e m s e l v e s w e r e r a t e d a l o n g w i t h t h e 160 anagrams. Each o f t h e 200 s t i m u l u s items a l o n g w i t h i t s r e s p e c t i v e a c c u r a c y , r e a c t i o n t i m e , and r a t i n g i s p r e s e n t e d i n Appendix 5.1. As d i s c u s s e d i n C h a p t e r 3 , a l a r g e number o f m e a s u r e s o f o r t h o g r a p h i c s t r u c t u r e b a s e d upon c o u n t s o f l e t t e r , “-gram, and word f r e q u e n c i e s may be computed. Q u a n t i t a t i v e m e a s u r e s b a s e d upon o r t h o g r a p h i c r u l e s a r e less r e a d i l y c o n s t r u c t e d . A l t h o u g h

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we d e v i s e d and t e s t e d one m e a s u r e o f r e g u l a r i t y b a s e d upon t h e r u l e s o u t l i n e d i n C h a p t e r 3 , w e c o n c e n t r a t e d upon f r e q u e n c y m e a s u r e s and q u e s t i o n s r e l a t e d t o t h e i r c o n s t r u c t i o n . The s p e c i f i c i s s u e s were a s f o l l o w s . Should f r e q u e n c y c o u n t s be based upon c o u n t s o f word t y p e s o r word t o k e n s ? What f r e q u e n c y s c a l e g i v e s t h e most p r e d i c t i v e i n d e x o f p e r f o r m a n c e , raw f r e q u e n c y o r some t r a n s f o r m e d f r e q u e n c y s c a l e s u c h a s l o g f r e q u e n c y ? Is p o s i t i o n a l d e p e n d e n c y , i . e . , w h e t h e r t h e c o u n t s p r e s e r v e p o s i t i o n o f t h e "-gram i n t h e sampled word, a n i m p o r t a n t f a c t o r ? What "-gram u n i t g i v e s t h e most p o w e r f u l measure: s i n g l e - l e t t e r , b i g r a m , o r t r i g r a m c o u n t s ? What i s t h e c o n t r i b u t i o n o f l e x i c a l s t a t u s and word f r e q u e n c y t o p e r f o r m a n c e ? And f i n a l l y , what method o f combining t h e f r e q u e n c i e s o f t h e components of a l e t t e r s t r i n g p r o v i d e t h e b e s t o v e r a l l i n d e x of i t s s t r u c t u r e ? T h e s e q u e s t i o n s w i l l be discussed i n t h e following s e c t i o n s .

DESCRIPTIVE MEASURES

The s o u r c e of a l l o u r f r e q u e n c y m e a s u r e s i s a word c o r p u s sampled by Kucera and F r a n c i s ( 1 9 6 7 ) . T h i s c o r p u s c o n s i s t e d o f 500 s a m p l e s o f a p p r o x i m a t e l y 2,000 words e a c h s e l e c t e d from 1 5 categories. A d e s c r i p t i o n of t h e c o r p u s , i t s s e l e c t i o n , and i t s processing are presented by K u c e r a and F r a n c i s . We o b t a i n e d a m a g n e t i c t a p e of t h e word c o u n t produced from t h e t h e "Rank L i s t " i n t h e K u c e r a and F r a n c i s corpus ( i . e . , monograph). The words were s o r t e d i n t o 1 0 l i s t s c o n s i s t i n g o f 1- t o 1 0 - l e t t e r words r e s p e c t i v e l y . Words l o n g e r t h a n 1 0 c h a r a c t e r s were d e l e t e d a s were items c o n t a i n i n g numbers, punctuation , o r s p e c i a l codings f o r c a p i t a l i z a t i o n s , foreign This a l p h a b e t s , and u n u s u a l g r a p h i c f e a t u r e s o r symbols. resulted i n 10 l i s t s of words, one f o r each l e t t e r length. T h e s e word l i s t s formed t h e b a s i s f o r c o u n t s o f s i n g l e l e t t e r s , b i g r a m s , and t r i g r a m s . T a b l e s were p r e p a r e d by c o u n t i n g t h e o c c u r r e n c e of e a c h -n-gram a t t h e p o s i t i o n i t o c c u r r e d i n words o f a g i v e n l e n g t h . Two c o u n t s were o t a i n e d . One was a t y p e c o u n t b a s e d upon t h e number of word t y p e s t h a t c o n t a i n e d a g i v e n E-gram, and t h e o t h e r was a t o k e n c o u n t b a s e d upon t h e t o t a l number o f A occurrences of the word containing the "-gram. position-insensitive c o u n t ( b u t s t i l l word l e n g t h d e p e n d e n t ) was a l s o o b t a i n e d f o r e a c h "-gram by summing a c r o s s t h e

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position-dependent c o u n t s . Because Kucera and Francis maintained a f a i t h f u l count o f t h e a c t u a l graphic p a t t e r n s fo u n d i n t h e c o r p u s , their list c o n t a i n s r a r e words, t y p o g r a p h i c e r r o r s , f o r e i g n p e r s o n and p l a c e n am es, a n d o t h e r i d e o s y n c r a t i c i t e m s . To l i m i t t h e i m p a c t o f s u c h items o n o u r l i m i t s were e s t a b l i s h e d f o r b o t h word t a b u l a t i o n s , cut-off f r e q u e n c y a n d number o f s a m p l e s . The c u t - o f f s were a minimum c o u n t o f a t l e a s t o n e o c c u r r e n c e i n t h r e e o f t h e 500 s a m p l e s . T h u s , u n u s u a l w o r d s and u s a g e s , r e g a r d l e s s o f t h e i r f r e q u e n c y , were i g n o r e d u n l e s s t h e y o c c u r r e d i n t h r e e o r m o r e s e p a r a t e s a m p l e s . I n t h i s way, w o r d s w i t h t h e minimum f r e q u e n c y o f t h r e e were c o u n t e d o n l y i f t h e y o c c u r r e d o n c e i n e a c h o f t h r e e s a m p l e s . A l t h o u g h t h i s l i m i t was a r b i t r a r y , i n s p e c t i o n o f t h e word l i s t i n t h e l o w f r e q u e n c y r a n g e i n d i c a t e d t h a t t h e s e were reasonable cut-offs. The s i n g l e - l e t t e r t o k e n c o u n t s f o r word l e n g t h s 3 t h r o u g h 7 a n d t h e b i g r a m t o k e n c o u n t s f o r word l e n g t h s 3 t h r o u g h 7 a r e p r e s e n t e d a s A p p e n d i c e s 5 .2 an d 5 . 3 , r e s p e c t i v e 1y All o f t h e f r e q u e n c y m e a s u r e s t h a t w i l l b e d i s c u s s e d were d e r i v e d f r o m t h e s e t a b l e s w i t h two e x c e p t i o n s , word f r e q u e n c y and E n g l i s h n e s s . The f r e q u e n c i e s o f t h e 40 w o r d s were t a k e n d i r e c t l y f r o m t h e K u c e r a and F r a n c i s c o u n t . E n g l i s h n e s s is a m e a s u r e p r o p o s e d b y T r a v e r s and O l i v i e r ( 1 9 7 8 ) and w as co m p u t ed from t a b l e s s u p p l i e d t o u s b y t h e a u t h o r s . E n g l i s h n e s s is a c o n t i n u e d p r o d u c t o f ;-gram probabilities estimated t o the l e v e l of third-order t r a n s i t i o n a l p r o b a b i l i t i e s . Th e f o r m u l a f o r s i x - l e t t e r words o r l e t t e r s t r i n g s i s a s f o l l o w s :

.

E n g l i s h n e s s (#LlL2L3L4L5L6#) = - l o g [P(L11#)*P(L2l#Ll)*P(L3lLlL2)* P(L41L2L3)*P(L51L3L4)*P(L61L4L5)1

(4)

w h e r e # r e p r e s e n t s a s p a c e and L i i s t h e l e t t e r a t p o s i t i o n i . The term P ( L k l L ( k - Z ) L ( k - l ) ) i s e s t i m a t e d by t h e r a t i o o f t h e t r i g r a m frequency o f L(k-Z)L(k-l)Lk t o t h e bigram frequency L(k-Z)L(k-l). I t should be noted that these frequency e s t i m a t e s a r e n o t p o s i t i o n s e n s i t i v e e x c e p t i n a s much a s t h e y the initial a r e tied t o i n i t i a l position occurrences, i.e., t r i g r a m # L 1 L 2 and i n i t i a l b ig ram # L 1 . The c o u n t s a r e a l s o n o t word-length specific. The i n i t i a l term P ( L i l # ) i n t h e f o r m u l a is a c t u a l l y t h e f r e q u e n c y o f t h e i n i t i a l l e t t e r a s i t o c c u r s i n t h e f i r s t p o s i t i o n i n words o f any l e n g t h . Th e r a t i o n a l e f o r e x a m i n i n g t h i s measure is t o p r o v i d e a c o m p a r i s o n t o t h e o t h e r f r e q u e n c y m e a s u r e s we w i l l e x a m i n e . T r a v e r s an d O l i v i e r ( 1 9 7 8 ) p r o v i d e d some e v i d e n c e t h a t t h e m e a s u r e had success i n

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d e s c r i b i n g performance i n a f u l l r e p o r t o f s h o r t p r e s e n t a t i o n s of l e t t e r s t r i n g s . Our r e g u l a r i t y m e a s u r e c o n s i s t e d o f a c o u n t of t h e number of i r r e g u l a r i t i e s c o n t a i n e d i n e a c h o f t h e 2 0 0 s t i m u l u s items. The e x a c t r u l e s f o r t h e i r r e g u l a r i t y count a r e given i n Table 5.1. An i r r e g u l a r i t y was c o u n t e d f o r e a c h v i o l a t i o n o f c e r t a i n s c r i b a l c o n s t r a i n t s , f o r e a c h i m p e r m i s s i b l e vowel c l u s t e r and f o r e a c h i m p o s s i b l e c o n s o n a n t c l u s t e r when c o n s i d e r e d a s p a r t of a m o n o s y l l a b l e . The items were t r e a t e d a s m o n o s y l l a b l e s b e c a u s e a n a p p r o p r i a t e s y l l a b i c a t i o n i s d i f f i c u l t t o impose on n o n s e n s e s t r i n g s . W i t h o u t r i g i d c r i t e r i a , j u d g m e n t s f o r some anagrams would be u n r e a s o n a b l y a r b i t r a r y . Thus, we c h o s e t o t r e a t a l l s t r i n g s a s monosyllabic even though t h i s r e q u i r e d c l a s s i f i c a t i o n of some two s y l l a b l e words a s c o n t a i n i n g irregularities at syllable b o u n d a r i e s . The counts of i r r e g u l a r i t i e s f o r e a c h o f t h e items o f e a c h o f t h e f i v e s t i m u l u s c a t e g o r i e s a r e shown i n Appendix 5 . 1 .

TYPE VERSUS TOKEN COUNTS

The f i r s t g e n e r a l i s s u e i n d e r i v i n g a f r e q u e n c y m e a s u r e i s whether type counts or token counts are most appropriate. C e r t a i n l y , t h e two methods o f c o u n t i n g w i l l produce frequency measures that have some d e g r e e of c o r r e l a t i o n . Even t h o u g h i t i s p r o b a b l y p o s s i b l e t o f i n d o c c u r r i n g i n o n l y a small number o f o c c u r r e n c e s o f “-grams e x t r e m e l y f r e q u e n t words and o t h e r E-grams o c c u r r i n g i n many i n f r e q u e n t word t y p e s , o n t h e a v e r a g e t h e g r e a t e r t h e t y p e count t h e g r e a t e r the token c o u n t . Only by e x a m i n i n g s i t u a t i o n s where t h e two m e a s u r e s a r e r e l a t i v e l y u n c o r r e l a t e d Thus, i f c a n t h e i m p o r t a n c e o f t h e two a p p r o a c h e s be measured. and our items e x h i b i t a s t r o n g c o r r e l a t i o n between t y p e t o k e n - b a s e d m e a s u r e s l i t t l e c a n be d e t e r m i n e d from o u r d a t a t o A t t h e same time, i f o u r s a m p l e is s u p p o r t one o v e r t h e o t h e r . r e p r e s e n t a t i v e of a w i d e r a n g e of l e t t e r s t r i n g s and t h e two a p p r o a c h e s a r e h i g h l y c o r r e l a t e d , t h e q u e s t i o n may b e o f no practical significance. I n any s i t u a t i o n where s u c h a m e a s u r e would be u s e f u l , e i t h e r m i g h t be used w i t h e s s e n t i a l l y identical effect. We found t h a t t h e c o r r e l a t i o n s between c o m p a r a b l e t y p e m e a s u r e s and t o k e n m e a s u r e s for our s a m p l e were v e r y h i g h . Measures b a s e d on s i n g l e l e t t e r s , b i g r a m s , and t r i g r a m s ,

ORTHOGRAPHIC STRUCTURE AND RECOGNITION

Table 5.1

The r u l e s f o r t h e i r r e g u l a r i t y c o u n t of stimulus items

129

the

200

1.

Segment s t r i n g i n t o vowel and c o n s o n a n t s u b s t r i n g s . Treat f i n a l -& a s i f i t w e r e -9. T r e a t between v o w e l s a s a ( l e g a l ) consonant.

2.

For e a c h c o n s o n a n t s t r i n g , d e t e r m i n e minimal number o f inserted t o make t h e s t r i n g vowels which m u s t b e pronounceable. I n i t i a l consonant c l u s t e r s m u s t be l e g a l in i n i t i a l position. F i n a l consonant c l u s t e r s m u s t be l e g a l i n f i n a l p o s i t i o n , i n c l u d i n g t h o s e f o l l o w e d by f i n a l -e . Medial c o n s o n a n t c l u s t e r s m u s t b e l e g a l i n i n i t i a l position.

3.

Rate each resulting consonant substring for p o s i t i o n - s e n s i t i v e s c r i b a l r e g u l a r i t y ( c o u n t one f o r e a c h irregular substring).

4.

For e a c h vowel s u b s t r i n g , d e t e r m i n e minimal number of c o n s o n a n t s which m u s t b e i n s e r t e d t o c r e a t e s c r i b a l l y r e g u l a r sequences. Mark a s i r r e g u l a r i l l e g a l i n i t i a l and f i n a l vowel s u b s t r i n g s .

5.

Count number of i n s e r t e d vowels and c o n s o n a n t s , p l u s number of s c r i b a l l y irregular consonant and vowel s u b s t r i n g s . T h i s y i e l d s an i r r e g u l a r i t y i n d e x .

6.

(among more o b v i o u s The vowel s t r i n g s ", E , s, and c a s e s ) would be i l l e g a l vowel s t r i n g s . y would be i l l e g a l a s a vowel i n i n i t i a l p o s i t i o n and i, 2 , a, E, and 9 would b e i l l e g a l i n f i n a l p o s t i o n . is l e g a l a s is y a s a s i n g l e , n o n - i n i t i a l vowel.

7.

h i s n o t a l l o w e d i n f i n a l p o s i t i o n u n l e s s p r e c e d e d by 9, Or S .

8.

y and y between v o w e l s a r e t o be c o u n t e d a s c o n s o n a n t s .

c,

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b o t h p o s i t i o n s e n s i t i v e and p o s i t i o n i n s e n s i t i v e , c o r r e l a t e d between . 8 4 and .99. With s u c h h i g h c o r r e l a t i o n s no m e a n i n g f u l d i s c r i m i n a t i o n c a n be made between t h e two a p p r o a c h e s . Figure 5 . 1 shows some 5-gram c o r r e l a t i o n s b a s e d on t y p e and t o k e n counts: t h e two sets of counts give highly similar correlations. For t h i s r e a s o n , u n l e s s o t h e r w i s e s t a t e d , we w i l l d i s c u s s o n l y m e a s u r e s based on t o k e n c o u n t s i n t h e remainder of t h i s c h a p t e r .

SCALE OF FREQUENCY

T h i s a n a l y s i s c o n c e r n s t h e f r e q u e n c y s c a l e t o be c h o s e n i n computing f r e q u e n c y m e a s u r e s . While t h e e f f e c t s o f f r e q u e n c y

Accuracy 0

B

LINEAR

Bigram Trigram

I

I

I

LOG

LINEAR

LOC

TYPE Figure 5.1

TOKEN

C o r r e l a t i o n s o f a c c u r a c y and r e a c t i o n times a s a f u n c t i o n o f l i n e a r o r l o g and t y p e o r t o k e n position-sensitive single-letter, bigram, and trigram counts.

ORTHOGRAPHIC STRUCTURE A N D RECOGNITION

131

seem t o b e p s y c h o l o g i c a l l y r e a l , i t i s n o t n e c e s s a r y t h a t t h e mental representations of frequency directly reflect the frequency o f o b j e c t i v e counts. One a l t e r n a t i v e s c a l e t h a t h a s b e e n s u c c e s s f u l i n o t h e r r e s e a r c h i s a l o g a r i t h m i c ( b a s e 10) scale. Not o n l y a r e t h e r e some d a t a t o s u g g e s t t h e p o s s i b i l i t y 1952; o f a l o g a r i t h m i c r e p r e s e n t a t i o n ( S o l o m o n 6, P o s t m a n , T a y l o r , 1977; T r a v e r s & O l i v i e r , 1978) , b u t a l s o a l o g a r i t h m i c representation i s c o n s i s t e n t w i t h r e c e n t s t u d i e s o f number representation (Shepard, 1978) and with many other psychological scales. T h e r e f o r e , w e computed a l l of our f r e q u e n c y m e a s u r e s b a s e d upon b o t h r e g u l a r l i n e a r frequencies and l o g f r e q u e n c i e s . For t h e s e measures, and a l l t r a n s f o r m e d tables for the scales ( t o be discussed) , linear-frequency position-dependent "-grams were n o t r e s c a l e d b e f o r e m e a s u r e s T h e r e f o r e , t h e two s e t s o f were computed f o r a n y item. m e a s u r e s b e i n g c o r r e l a t e d were s u m s o f p o s i t i o n - d e p e n d e n t single letters, bigrams, and t r i g r a m s d e r i v e d from e i t h e r linear-frequency o r log-frequency tables. In nearly every i n s t a n c e t h e l o g - f r e q u e n c y m e a s u r e was m o r e h i g h l y c o r r e l a t e d w i t h t h e p e r f o r m a n c e m e a s u r e t h a n was l i n e a r f r e q u e n c y ( s e e , f o r example, F i g u r e 5 . 1 ) . Although log f r e q u e n c i e s , f o r purposes o f d e s c r i b i n g t h e e f f e c t s of o r t h o g r a p h i c s t r u c t u r e on r e c o g n i t i o n performance, were b e t t e r t h a n l i n e a r f r e q u e n c i e s , w e were a l s o i n t e r e s t e d i n comparing t h e l o g s c a l e w i t h o t h e r transformations of the linear freqencies. For t h i s i n v e s t i g a t i o n , w e c h o s e o u r b e s t f r e q u e n c y m e a s u r e , summed t o k e n p o s i t i o n - s e n s i t i v e b i g r a m s , a n d a p p l i e d a r a n g e o f t r a n s f o r m a t i o n s t o i t . A power f u n c t i o n o f t h e form X

y = a

(5)

gave v a r i o u s s c a l e s depending on t h e v a l u e of t h e exponent x. The E x p o n e n t s o f 0 . 8 , 0 . 7 , 0 . 5 , 0 . 2 , a n d 0 . 1 were s e l e c t e d . 0.2 exponent approximates t h e log function very c l o s e l y i n t h e range of f r e q u e n c y v a l u e s r e p r e s e n t e d by o u r s t i m l u i . The l a r g e r exponents y i e l d e d v a l u e s i n t e r m e d i a t e between t h o s e of log s c a l e s w h i l e t h e 0 . 1 exponent produced t h e l i n e a r and v a l u e s more e x t r e m e t h a n t h e l o g function. The c o r r e l a t i o n between t h e s e b i g ram m e a s u r e s and t h r e e per f or m ance m e a s u r e s g r e w m o n o t o n i c a l l y f r o m t h e l i n e a r s c a l e m e a s u r e t o t h e l o g and 0.2 e x p o n e n t power f u n c t i o n w h e r e c o r r e l a t i o n s p e a k e d and t h e n f e l l f o r ' t h e m o r e e x t r e m e 0 . 1 e x p o n e n t power function. The c o r r e l a t i o n s between a v e r a g e a c c u r a c y and t h e s e bigram measures were . 6 3 f o r t h e l i n e a r s c a l e ; . 7 7 f o r t h e l o g s c a l e ; a n d .68,

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. 7 0 , . 7 4 , . 7 7 , .75 f o r e x p o n e n t s of 0 . 8 , 0 . 7 , 0 . 5 , 0 . 2 , and 0 . 1 respectively. These d a t a i n d i c a t e t h a t i f f r e q u e n c y m e a s u r e s a r e u t i l i z e d by t h e r e a d e r , t h e y a p p e a r t o be computed o n l o g f r e q u e n c i e s , and s o o n l y log-frequency m e a s u r e s w i l l be discussed further.

POSITION-SENSITIVE VERSUS POSITION-INSENSITIVE COUNTS

T h e r e have been many a t t e m p t s t o d e r i v e a m e a s u r e o f p e r c e p t a b i l i t y b a s e d upon p o s i t i o n - i n s e n s i t i v e f r e q u e n c y c o u n t s 1954; (Gibson 1 9 6 4 ; G i b s o n , e t a l . , 1970; Postman & Conger, Spoehr & S m i t h , 1 9 7 5 ) . T h e s e a t t e m p t s h a v e t y p i c a l l y shown t h a t counts t h a t accumulate frequencies without regard t o p o s i t i o n give inadequate m e a s u r e s . On the o t h e r hand, p o s i t i o n - s e n s i t i v e m e a s u r e s h a v e r e c e i v e d some s u p p o r t a s y i e l d i n g b e t t e r m e a s u r e s ( G i b s o n e t a l . , 1 9 7 0 ; Mason, 1 9 7 5 , McClelland & J o h n s t o n , 1 9 7 7 ) . We compared t h e two t y p e s o f measures a g a i n s t our d a t a . T a b l e 5 . 2 shows t h e c o r r e l a t i o n s between t h e t h r e e p e r f o r m a n c e m e a s u r e s w i t h s i n g l e - l e t t e r , b i g r a m , and t r i g r a m c o u n t s d e r i v e d from b o t h p o s i t i o n - s e n s i t i v e and p o s i t i o n - i n s e n s i t i v e c o u n t s . The s t r i k i n g d i f f e r e n c e i n t h i s t a b l e is between t h e two d i f f e r e n t s i n g l e - l e t t e r m e a s u r e s . A s n o t e d by e a r l i e r r e s e a r c h e r s ( e . g . , Postman & Conger, 1 9 5 4 ) , o v e r a l l l e t t e r frequency without regard t o p o s i t i o n is not a very powerful predictor of r e c o g n i t i o n performance. By c o n t r a s t , a p o s i t i o n - d e p e n d e n t s i n g l e - l e t t e r m e a s u r e is a l m o s t a s p o w e r f u l a s p o s i t i o n - i n s e n s i t i v e b i g r a m s and t r i g r a m s f o r RT. It should be noted t h a t d e s c r i b i n g a c c u r a c y and position-insensitive c o u n t s d o b e t t e r a s t h e =-gram's length increases. For "-grams of a g i v e n l e n g t h , p o s i t i o n d e p e n d e n c e seems t o l e a d t o a b e t t e r i n d e x of s t r u c t u r e a l t h o u g h t h e a d v a n t a g e is e s s e n t i a l l y e l i m i n a t e d f o r t r i g r a m c o u n t s . The apparent s u p e r i o r i t y of position-sensitive bigrams over For t h e position-sensitive t r i g r a m s w i l l be d i s c u s s e d n e x t . r e m a i n d e r of t h e s e a n a l y s e s , p o s i t i o n - s e n s i t i v e c o u n t s w i l l be used.


T a b l e 5.2

!&pe

133

C o r r e l a t i o n s between t h e t h r e e dependent an d summed l o g f r e q u e n c y c o u n t s , b o t h d e p e n d e n t and p o s i t i o n i n d e p e n d e n t .

o f Frequen cy Measure

measures position

Dependent Measures

Accuracy

RT -

Rat inq

P o s i t i o n Independent Single Letter

.20

-.36

.04

B i g r am

.59

-.55

.73

Trigram

.68

-.57

.84

Single Letter

.62

-.48

.45

B i g r am

.77

-.64

.83

T r i g r am

.75

-.54

.80

P o s i t i o n Dependent

THE MOST EFFECTIVE FREQUENCY MEASURE

We h a v e n o t e d t h a t summed p o s i t i o n - s e n s i t i v e l o g b i g r a m f r e q u e n c i e s had t h e h i g h e s t c o r r e l a t i o n s w i t h our t h r e e p e r f o r m a n c e m e a s u r e s . T h i s measure, i n f a c t , h ad t h e h i g h e s t frequency c o r r e l a t i o n s o f any of t h e a l m o s t 5 0 forms o f measures t h a t w e examined. For example, p o s i t i o n - s e n s i t i v e s i n g l e l e t t e r s account f o r an average of 29% of the variance in our t h r e e performance measures, while position-sensitive b i g r a m s a c c o u n t f o r 57%. Although it m i g h t b e e x p e c t e d t h a t l a r g e r !-grams s h o u l d n a t u r a l l y c a p t u r e more o r t h o g r a p h i c structure than smaller E-grams, we observed that position-sensitive bigram c o u n t s of s e v e r a l kinds (discussed below) were b e t t e r t h a n comparable f r e q u e n c y measures based

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upon t r i g r a m s . I t is p o s s i b l e t o h y p o t h e s i z e s e v e r a l r e a s o n s why t h i s s h o u l d be t h e c a s e . F i r s t , t h e sampling e r r o r i n t h e t r i g r a m t a b l e s may be l a r g e enough r e l a t i v e t o t h e s a m p l i n g e r r o r i n t h e b i g r a m t a b l e s t o a c c o u n t f o r t h e e f f e c t . The rough equivalence between p o s i t ion- i n d e p e n d e n t and position-dependent t r i g r a m c o u n t s m i g h t h a v e r e s u l t e d from a t r a d e - o f f between t h e a d v a n t a g e of p o s i t i o n s e n s i t i v i t y and t h e larger error variance for position-sensitive c o u n t s . Second, t r i g r a m s s i m p l y may h a v e r e a c h e d a p o i n t o f d i m i n i s h i n g returns. With b i g r a m s a c c o u n t i n g f o r 5 7 % o f t h e v a r i a n c e , t h e r e s i m p l y may b e no room f o r n o t i c e a b l e improvements w i t h l a r g e r "-gram measures. Finally, i t c o u l d be t h a t b i g r a m c o u n t s a r e more r e p r e s e n t a t i v e of t h e r e a d e r ' s knowledge and u t i l i z a t i o n o f o r t h o g r a p h i c s t r u c t u r e . We w i l l r e t u r n t o t h i s q u e s t i o n i n a l a t e r s e c t i o n of t h i s c h a p t e r . The m e a s u r e s t h a t have been d i s c u s s e d w e r e b a s e d upon t h e s u m o f t h e f r e q u e n c i e s f o r t h e component "-grams i n a l e t t e r string. E n g l i s h n e s s was d e s c r i b e d a s a p r o d u c t of f r e q u e n c y r a t i o s and would a p p e a r t o p r o v i d e a n i n t e r e s t i n g c o m p a r i s o n i n t e r m s o f how a f r e q u e n c y m e a s u r e s h o u l d be computed from component "-gram frequencies. The observation t h a t log f r e q u e n c y i s a b e t t e r s c a l e n a r r o w s t h e d i s t a n c e between E n g l i s h n e s s and summed "-gram m e a s u r e s s i n c e E n g l i s h n e s s is computed a s t h e s u m o f t h e l o g a r i t h m s o f f r e q u e n c y r a t i o s . In a c t u a l c o m p a r i s o n , E n g l i s h n e s s p r o v e d t o be a l e s s p o w e r f u l It measure t h a n the position-dependent bigram m e a s u r e . c o r r e l a t e d - . 6 5 w i t h a v e r a g e a c c u r a c y , . 4 7 w i t h a v e r a g e RT, and -.a2 with the ratings. I t o c c u r r e d t o u s t h a t t h e n o r m a l i z a t i o n p r o c e s s of d i v i d i n g a t r i g r a m f r e q u e n c y by t h e t o t a l f r e q u e n c y o f a l l r e l a t e d t r i g r a m s might have t h e p o t e n t i a l f o r producing an is essentially what extremely powerful measure. That Englishness does except that it is based upon p o s i t i o n - i n s e n s i t i v e c o u n t s . T h i s would make p a r t i c u l a r l y good t h e o r e t i c a l s e n s e i n t h e case where p a r t i a l v i s u a l i n f o r m a t i o n was a v a i l a b l e and was used t o r e s o l v e O K e s t i m a t e unknown letters. For e x a m p l e , i f some t r i g r a m xyz i s c o n s i d e r e d a t some p o i n t i n a l e t t e r s t r i n g , t h e p r e d i c t a b i l i t y o f z g i v e n t h e p r e c e e d i n g l e t t e r s xy i s a f u n c t i o n of t h e f r e q u e n c y o f xyz r e l a t i v e t o t h e t o t a l f r e q u e n c y of a l l t r i g r a m s xy-, where t h e f i n a l l e t t e r r a n g e s o v e r t h e e n t i r e a l p h a b e t and t a k e s on a l l a c t u a l l y o c c u r r i n g v a l u e s . Of c o u r s e , c o n s t r a i n t s need n o t work o n l y f o r w a r d , t h e r a t i o s xyz/x-z and xyz/-yz a r e a l s o o f interest. Analogously, r a t i o s o f p a r t i c u l a r b i g r a m s xy t o t h e g e n e r a l b i g r a m s u m s x- and -y c a n be computed.

ORTHOGRAPHIC STRUCTURE AND R E C O G N I T I O N

T a b l e 5.3

C o r r e l a t i o n s between t h e p e r f o r m a n c e m e a s u r e s and summed b i g r a m , E n g l i s h n e s s , and c o n s t r a i n t - r a t i o m e a s u r e s a l l based on l o g word-token f r e q u e n c i e s .

F r e q u e n c y Measure

P e r f o r m a n c e Measure Accuracy

Summed Bigrams Englishness

135

.77 -.65

RT -

-.64 .47

Rating .85 -.82

XYd X Y -

.75

-.55

.81

X Y z/x-z

.74

-.5 6

.82

XY4

.74

-.54

.80

XY/X-

.76

-.64

.86

XY1-Y

.75

-.64

.85

-Y

These f i v e c o n s t r a i n t r a t i o s s u g g e s t f i v e p o t e n t i a l l y i n t e r e s t i n g m e a s u r e s d e r i v e d by summing t h e f o u r t r i g r a m c o n s t r a i n t r a t i o s o r f i v e bigram c o n s t r a i n t r a t i o s f o r our six-letter s t r i n g s . Again, t h e m e a s u r e s were computed a s r a t i o s o f l i n e a r f r e q u e n c i e s and a s r a t i o s o f l o g f r e q u e n c i e s . The c o u n t s c o u l d be based on word-type frequencies or word-token frequencies. In t h i s case, y e t another type frequency. Letter-type frequency is p o s s i b l e , l e t t e r - t y p e f r e q u e n c y i s s i m p l y t h e number of l e t t e r s t h a t a c t u a l l y o c c u r in the f r e e variable position. Thus, a t r i g r a m of t h e form s-r m i g h t c o n s i s t of a f a m i l y o f e i g h t o r n i n e t r i g r a m s w h i l e q-i h a s o n l y a s i n g l e p o s s i b l e member. L e t t e r - t y p e f r e q u e n c y was t a k e n a s t h e r e c i p r o c a l number of t r i g r a m s i n a f a m i l y o r z e r o i f t h e f a m i l y h a s no n a t u r a l l y o c c u r r i n g member, i.e., all A similar letter-type measure was illegal trigrams. constructed f o r bigrams. I n a l l , t h e r e were 3 0 measures computed from c o n s t r a i n t r a t i o s ( f i v e k i n d s of r a t i o s x two f r e q u e n c y s c a l e s x t h r e e k i n d s o f t y p e and t o k e n c o u n t s ) .

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The r e s u l t s f o r t h e s e c o n s t r a i n t - r a t i o m e a s u r e s m i r r o r e d t h e r e s u l t s f o r t h e s i m p l e summed fi-gram frequencies. Ratios of log frequencies c o n s i s t e n t l y gave higher c o r r e l a t i o n s than r a t i o s of l i n e a r frequencies. Word-token f r e q u e n c i e s and word-type f r e q u e n c i e s were n e a r l y i n d i s t i n g u i s h a b l e i n terms o f t h e i r c o r r e l a t i o n s with the performance measures; t h e s e f r e q u e n c y m e a s u r e s c o r r e l a t e d w i t h e a c h o t h e r a t .90 o r h i g h e r . Letter-type f r e q u e n c i e s c o r r e l a t e d s l i g h t l y less h i g h l y with word-type and word-token f r e q u e n c y m e a s u r e s b u t a l s o d i d n o t c o r r e l a t e a s h i g h l y w i t h t h e performance measures. Finally, t h e bigram r a t i o measures gave s l i g h t l y h i g h e r c o r r e l a t i o n s with t h e performance measures t h a n d i d t h e t r i g r a m r a t i o s . A representative s a m p l e of t h e s e m e a s u r e s i s shown i n T a b l e 5 . 3 . C o r r e l a t i o n s among t h e f r e q u e n c y m e a s u r e s were q u i t e h i g h . The t h r e e t r i g r a m m e a s u r e s shown i n T a b l e 5 . 3 c o r r e l a t e d w i t h e a c h

.a

-

.4 -

.6

H Bd

.2-

.o-

K K 0 -.2 0

-

-.4

-

-.6

-

-.8

-

-1.0

I

o

x

Blgram Trlgram

I

I

I

I

I

I

1

2

3

4

5

6

SERIAL POSITION Figure 5.2

C o r r e l a t i o n s o f a c c u r a c y and r e a c t i o n t i m e s w i t h s i n g l e - l e t t e r , b i g r a m , and t r i g r a m f r e q u e n c i e s a s a f u n c t i o n of t h e i r r e s p e c t i v e s e r i a l p o s i t i o n s i n the six-letter strings.


137

L i k e w i s e , t h e two b i g r a m c o n s t r a i n t - r a t i o o t h e r .98 or h i g h e r . m e a s u r e s c o r r e l a t e d . 9 9 w i t h e a c h o t h e r . Given t h e u n i f o r m l y h i g h c o r r e l a t i o n s between a l l t h e c o n s t r a i n t - r a t i o m e a s u r e s , i t i s i m p o s s i b l e t o d i s c r i m i n a t e among them. F u r t h e r m o r e , these r a t i o s do not account f o r any more v a r i a n c e t h a n t h e c o m p u t a t i o n a l l y s i m p l e r summed l o g b i g r a m m e a s u r e . For t h e s e r e a s o n s , t h e summed l o g b i g r a m m e a s u r e is t o be p r e f e r r e d o v e r the constraint ratios. Having found t h a t computing more complex m e a s u r e s was no more e f f e c t i v e t h a n summing t h e component b i g r a m s o f a l e t t e r s t r i n g , w e i n v e s t i g a t e d a s i m p l e r m e a s u r e . We examined t h e c o r r e l a t i o n s o f t h e f r e q u e n c i e s of e a c h o f t h e component -n-grams w i t h t h e p e r f o r m a n c e m e a s u r e s . Thus, t h e r e were s i x c o r r e l a t i o n s f o r s i n g l e - l e t t e r f r e q u e n c i e s , f i v e f o r bigram f r e q u e n c i e s , and f o u r f o r t r i g r a m f r e q u e n c i e s with each

.3

0

8 o”

t

-6

.2-

- 4

.l-

0

g

K 40-

- 6

30-

20 -

SERIAL POSITION Figure 5 . 3

V a r i a n c e s of s i n g l e - l e t t e r and b i g r a m o c c u r r e n c e s along with their observed c o r r e l a t i o n s with accuracy measures at the respective serial positions in the six-letter strings.

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performance measure. F i g u r e 5.2 p r e s e n t s t h e r e s u l t s o f t h i s analysis. A l t h o u g h some o f t h e i n d i v i d u a l "-grams d i d n e a r l y a s w e l l a s t h e summed m e a s u r e s , n o s i n g l e "-gram u n i t had a s h i g h a c o r r e l a t i o n a s i t s c o r r e s p o n d i n g summed m e a s u r e . I t is a p p a r e n t f r o m t h e f i g u r e t h a t t h e e n d l e t t e r p o s i t i o n s were t h e most i m p o r t a n t , b u t a s t h e 3-gram length increased the p o s i t i o n a l d i f f e r e n c e s w e re d i m i n i s h e d F i g u r e 5. 2 shows t h a t t h e d e g r e e t o which a p a r t i c u l a r n-gram p r e d i c t s p e r f o r m a n c e is c r i t i c a l l y d e p e n d e n t o n i t s s e r i a l p o s i t i o n , e s p e c i a l l y f o r t h e s i n g l e - l e t t e r an d t o some e x t e n t t h e bigram c o u n t s . I n o r d e r t o e v a l u a t e whether t h i s e f f e c t is due t o t h e i n f o r m a t i o n a l c o n s t r a i n t s i n t h e s t i m u l i themselves, we derived a measure af redundancy or p r e d i c t a b i l i t y f o r each serial position. The v a r i a n c e o f l e t t e r o c c u r r e n c e s a t e a c h s e r i a l p o s i t i o n w as co m p u t ed b a s e d on t h e t a b l e o f f r e q u e n c i e s g i v e n i n Appendix 5 . 2 a n d 5.3. H i g h v a r i a n c e s o c c u r t o t h e e x t e n t t h a t some l e t t e r s o c c u r more o f t e n t h a n o t h e r s . These v a r i a n c e measures f o r t h e As single-letter and b i g r a m c o u n t s a r e shown i n F i g u r e 5 .3 . m i g h t b e e x p e c t e d f r o m p h o n o l o g i c a l and s c r i b a l c o n s t r a i n t s , l e t t e r s a r e much m o r e p r e d i c t a b l e i n i n i t i a l and f i n a l positions than in the middle of s i x - l e t t e r w o r d s. Also presented i n Figure 5.3 are t h e corresponding c o r r e l a t i o n s with t h e accuracy measure. The v a r i a n c e a nd c o r r e l a t i o n m e a s u r e s a r e h i g h l y c o r r e l a t e d f o r s i n g l e - l e t t e r c o u n t s w h i ch m ean s t h a t s u b j e c t s e x p l o i t redundancy d i r e c t l y t o t h e degree t h a t i t is present. Although t h i s correspondence m i g h t b e e x p e c t e d t o occur necessarily, the bigram results argue the o p p o s i t e . Although t h e v a r i a n c e measures a r e roughly s i m i l a r f o r t h e f i r s t t h r e e s e r i a l p o s i t i o n s , t h e c o r r e l a t i o n s a r e much h i g h e r f o r t h e f i r s t two p o s i t i o n s t h a n f o r t h e t h i r d . In a d d i t i o n , a l t h o u g h t h e f i n a l b i g r a m i s much m o r e p r e d i c t a b l e t h a n t h e p e n u l t i m a t e b i g r a m , t h e c o r r e l a t i o n s d o n o t d i f f e r by much.

.

FREQUENCY VERSUS R E G U L A R I T Y

A major concern of t h e p r e s e n t r e s e a r c h h a s been t o c o m p ar e f r e q u e n c y w i t h r u l e - g o v e r n e d r e g u l a r i t y a s i n d i c e s o f 3 t h e form of s t r u c t u r e . We h a v e d i s c u s s e d i n C h a p t e r e x p e r i m e n t a t i o n t h a t w i l l need t o b e c o n d u c t e d t o f u r t h e r d i f f e r e n t i a t e t h e s e two i n d i c e s . We h a v e p r e s e n t e d e v i d e n c e i n


139

Chapter 4 t h a t r e g u l a r i t y i s a t l e a s t a s important f o r p e r c e p t u a l r e c o g n i t i o n and more i m p o r t a n t f o r o v e r t j u d g m e n t s a s is s i n g l e - l e t t e r p o s i t i o n a l frequency. In t h e p r e s e n t c h a p t e r , w e h a v e shown t h a t s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y is a good m e a s u r e b u t t h a t b i g r a m p o s i t i o n a l f r e q u e n c y i s a W e h a v e examined s e v e r a l d i m e n s i o n s o f the b e t t e r measure. f r e q u e n c y domain and p r e s e n t e d s e v e r a l f i n d i n g s a b o u t f r e q u e n c y measures. T h i s i n v e s t i g a t i o n of t h e q u a n t i t a t i v e a s p e c t s of f r e q u e n c y m e a s u r e s was r e l a t i v e l y d i r e c t and s t r a i g h t f o r w a r d . A comparable i n v e s t i g a t i o n i s n o t p o s s i b l e f o r r e g u l a r i t y . We h a v e made o n l y a v e r y modest s t a r t . A s a n i n i t i a l e f f o r t t o q u a n t i f y r e g u l a r i t y , w e computed a s i m p l e c o u n t of o r t h o g r a p h i c i r r e g u l a r i t i e s b a s e d upon o u r p r e l i m i n a r y a t t e m p t a t a grammar of o r t h o g r a p h y ( s e e T a b l e 5 . 1 ) . The r e s u l t d o e s r a t h e r w e l l i n c o r r e l a t i n g w i t h p e r f o r m a n c e m e a s u r e s b u t is n o t s u f f i c i e n t l y developed t o a l l o w f o r a d e c i s i v e comparison w i t h bigram f r e q u e n c y . The r e g u l a r i t y c o u n t c o r r e l a t e d . 5 7 w i t h a v e r a g e accuracy, -.53 with average RT, and .85 with the ratings. Although t h e s e c o r r e l a t i o n s w i t h t h e two r e c o g n i t i o n m e a s u r e s a r e q u i t e modest i n c o m p a r i s o n w i t h t h e f r e q u e n c y measures described i n t h i s c h a p t e r , the correlation with r a t i n g s i s c o m p a r a b l e w i t h t h e b e s t f r e q u e n c y m e a s u r e . While we h e s i t a t e t o d r a w s t r o n g c o n c l u s i o n s , i t would a p p e a r t h a t potential for developing not only refined t h e r e is rule-governed measures but a l s o q u a n t i t a t i v e l y u s e f u l s t r u c t u r e i n d i c e s b a s e d upon t h e s e r u l e s . One m a j o r p r o b l e m w i t h d i s t i n g u i s h i n g between f r e q u e n c y and r e g u l a r i t y m e a s u r e s o f o r t h o g r a p h i c s t r u c t u r e is t h a t t h e s e two m e a s u r e s a r e n a t u r a l l y c o r r e l a t e d i n t h e w r i t t e n I t is p o s s i b l e t o u n t a n g l e t h e s e m e a s u r e s a s we d i d language. i n the present studies. However, by i n d e p e n d e n t l y v a r y i n g single-letter p o s i t i o n a l f r e q u e n c y and r e g u l a r i t y , we a c t u a l l y c r e a t e d l e t t e r s t r i n g s t h a t v a r i e d s y s t e m a t i c a l l y w i t h bigram f r e q u e n c y . Our r e g u l a r s t r i n g s were h i g h e r i n b i g r a m f r e q u e n c y than the corresponding irregular strings. Therefore, r e g u l a r i t y and position-sensitive log bigram frequency i n our l i s t of 2a8 t e s t ite m s. I n f u t u r e c o r r e l a t e d .759 e x p e r i m e n t s , w e p l a n t o i n d e p e n d e n t l y v a r y t h e s e two m e a s u r e s of o r t h o g r a p h i c s t r u c t u r e i n p e r c e p t u a l r e c o g n i t i o n and o v e r t judgment e x p e r i m e n t s .

CHAPTER 5

140

W I T H I N CLASS ANALYSIS

All of t h e a n a l y s e s p r e s e n t e d s o f a r i n t h i s c h a p t e r have examined c o r r e l a t i o n s between m e a s u r e s computed f o r t h e items a c r o s s t h e f i v e c l a s s e s of s t i m u l u s s t r i n g s . Whereas i t i s v e r y i m p o r t a n t t o e x p l a i n t h i s between c l a s s v a r i a n c e , i t i s e q u a l l y i m p o r t a n t t o examine how w e l l s e v e r a l m e a s u r e s o f orthographic s t r u c t u r e explain t h e variance within each c l a s s . To d o t h i s , t h e c o r r e l a t i o n a l a n a l y s e s were r e p e a t e d s e p a r a t e l y for the words and the regular-high, regular-low, irregular-high, and i r r e g u l a r - l o w anagram c l a s s e s . Figure 5 . 4 presents the correlations for the three position-sensitive log

3

x

Bigram Trigram

:" '

.4

-.6

-.8 -1.0

Figure 5 . 4

c WORDS

Reaction Time

R-H

R-L

I-H

I-L

C o r r e l a t i o n s o f a c c u r a c y and r e a c t i o n times a s a f u n c t i o n of s i n g l e - l e t t e r , b i g r a m , and t r i g r a m f r e q u e n c i e s f o r each of t h e f i v e - l e t t e r s t r i n g types.


141

n-gram counts with the accuracy and RT performance A s c a n be s e e n i n t h e f i g u r e , t h e m o s t s i g n i f i c a n t measures. r e s u l t is t h e r e l a t i v e l y poor c o r r e l a t i o n s o f p e r f o r m a n c e w i t h trigram frequencies. S i n g l e l e t t e r and bigram f r e q u e n c i e s d o Finally, a l l correlations for the about equally w e l l overall. This l a t t e r r e s u l t might word RT d a t a were c l o s e t o z e r o . i n d i c a t e t h a t l e x i c a l s t a t u s makes a unique c o n t r i b u t i o n i n t h e RT t a s k attenuating the contributions of orthographic s t r u c t u r e . Future research w i l l be necessary t o address t h i s issue.

WORD FREQUENCY

An a d d i t i o n a l m e a s u r e o f i n t e r e s t i s word f r e q u e n c y . Word f r e q u e n c y h a s shown t o b e a g o o d p r e d i c t o r o f word r e c o g n i t i o n ( B r o a d b e n t , 1 9 6 7 ) . Log word f r e q u e n c y c o r r e l a t e s . 6 4 w i t h a v e r a g e a c c u r a c y and .62 w i t h r a t i n g s ; however, f o r j u s t t h e word items the correlations are -.27 and -.11 respectively. T h i s means t h a t word frequency cannot be d i r e c t l y r e s p o n s i b l e f o r t h e e f f e c t s o f o r t h o g r a p h y s i n c e much higher c o r r e l a t i o n s should have been seen i n t h e c l a s s o f words. I n f a c t , a dummy v a r i a b l e a s s i g n i n g t h e v a l u e 1 t o a l l words and 0 t o a l l nonwords c o r r e l a t e s .66 w i t h a v e r a g e Log word f r e q u e n c y c o r r e l a t e s a c c u r a c y and .63 w i t h r a t i n g s . .52 a n d . 7 8 w i t h p o s i t i o n - s e n s i t i v e l o g b i g r a m a n d t r i g r a m f r e q u e n c i e s r e s p e c t i v e l y i n o u r s e t o f 200 i t e m s . T h e r e f o r e , l e x i c a l s t a t u s i t s e l f a p p e a r s t o c o n t r i b u t e v e r y l i t t l e beyond what c a n b e a c c o u n t e d f o r b y s u b l e x i c a l o r t h o g r a p h i c s t r u c t u r e .

YULTI P L E REGRESS1 ON

A s e r i e s o f m u l t i p l e r e g r e s s i o n a n a l y s e s were c a r r i e d o u t t o s e e how much o f t h e v a r i a n c e o f e a c h o f t h e d e p e n d e n t measures could be accounted f o r b y some c o m b i n a t i o n o f d e s c r i p t i v e measures. For response accuracy, l o g bigram f r e q u e n c y , l o g word f r e q u e n c y , a n d l o g s i n g l e - l e t t e r f r e q u e n c y a c c o u n t e d f o r a t o t a l o f 6 8 % o f t h e v a r i a n c e . No o t h e r d e s c r i p t i v e v a r i a b l e i m p r o v e d o n t h e 4 0 % o f t h e RT v a r i a n c e a c c o u n t e d f o r by l o g bigram f r e q u e n c y . F i n a l l y , 88% of t h e

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variance of t h e r a t i n g judgments was a c c o u n t e d f o r by r e g u l a r i t y count, log trigram frequency, a n d l o g word show that the k n o w l ed g e of frequency. These r e s u l t s o r t h o g r a p h i c s t r u c t u r e r e v e a l e d by a n o v e r t judgment t a s k d o e s n o t r e v e a l i t s e l f t o t h e same d e g r e e i n p e r c e p t u a l r e c o g n i t i o n tasks. T h i s r e s u l t is not unreasonable considering t h e additional v i s u a l processing requirements i n the perceptual recognition tasks. In addition, t h e accuracy task allows a s i g n i f i c a n t l y l a r g e r c o n t r i b u t i o n of o r t h o g r a p h i c s t r u c t u r e The r e a s o n f o r t h i s d i f f e r e n c e a p p e a r s t h a n d o e s t h e RT t a s k . t o be due t o t h e r e l a t i v e l y small c o n t r i b u t i o n of v i s u a l p r o c e s s i n g t o t h e RT m e a s u r e c o m p a r e d t o t h e r e l a t i v e l y l a r g e c o n t r i b u t i o n of v i s u a l processing t o t h e accuracy measure (see Chapter 4 ) .

SUMMARY

The p o s t h o c c o r r e l a t i o n s were r e a s o n a b l y s u c c e s s f u l in i l l u m i n a t i n g t h e r o l e o f a number o f v a r i a b l e s r e l e v a n t t o m e a s u r e s o f o r t h o g r a p h i c s t r u c t u r e . Type an d t o k e n c o u n t s were e q u a l l y good m e a s u r e s f o r o u r s t i m u l u s items, wher eas l o g c o u n t s were s i g n i f i c a n t l y b e t t e r t h a n l i n e a r c o u n t s . Position counts. s e n s i t i v i t y i s c r i t i c a l , e s p e c i a l l y f o r s m a l l e r !-gram F i n a l l y , p o s i t i o n - s e n s i t i v e l o g bigram f r e q u e n c y appeared t o be t h e m o s t e f f e c t i v e m e a s u r e , a l t h o u g h t h e r e a p p e a r s t o b e some p o t e n t i a l f o r d e v e l o p i n g a n e q u a l l y good r e g u l a r i t y m easur e.

APPENDIX 5.1

143

Appendix 5.1 S t i m u l u s Items a n d R e s u l t s E a c h o f t h e 2 0 0 s t i m u l u s items a n d i t s r e s p e c t i v e a v e r a g e p e r c e n t a g e a c c u r a c y (Acc) , a v e r a g e RT, a v e r . a g e r a t i n g , summed p o s i t i o n - s e n s i t i v e l o g s i ng le- 1e t t e r f r e q u e n c y , summed PO si t i o n - s e n s i t i v e l o g b i g ram f r e q u e n c y , summed p o s i t i o n - s e n s i t i v e log trigram f r e q u e n c y , l o g word f r e q u e n c y , a n d number o f irregularities

.

CHAPTER 5

144

WORDS

action amount answer barely belong breath bridge charge double f am o u s finger garden gather glance hardly itself lawyer longer master modern mother namely nearly permit player poetry purely reason r em ai n result shared s imp1 e single spread stared stream travel trials turned winter

Acc

RT

%

msec

81 77 89 89 89 86 94 86 92 89 92 93 89 87 89 79 86 94 93 93 93 90 89 83 95 93 92 85 85 86 93 91 91 91 95 89 85 82 85 91

644 6 56 644 635 603 629 654 642 621 639 653 619 673 637 661 637 646 627 627 616 610 662 620 590 619 642 607 605 638 636 640 622 632 611 672 616 622 623 675 621

Rating

8.8 9.3 8.2 9.3 9.5 9.3 8.9 9.4 8.9 8.9 9.5 9.7 9.4 9.3 9.4 9.2 8.7 9.6 9.7 9.5 9.5 9.4 9.3 9.6 9.6 9.2 9.1 9.1 9.5 9.7 9.4 9.4 9.2 9.2 9.4 9.5 9.6 9.2 9.3 9.7

Single Letter

Bigram T r i g r a m

22.33 21.83 22.10 23.30 22.76 21.48 21.94 22.28 22.13 22.05 22.80 22.75 22.87 21.77 22.49 21.03 21.60 22.96 23.55 22.33 23.31 22.53 22.52 22.52 21.85 22.80 23.03 22.46 22.19 23.02 23.55 22.94 23.02 22.60 23.44 21.94 21.87 22.53 23.42 23.11

15.26 14.12 14.08 15.63 15.12 13.56 13.05 14.51 13.56 13.34 15.58 14.26 15.91 13.70 14.87 13.63 12.50 15.67 16.56 14.40 16.47 14.84 14.76 14.16 14.61 12.36 15.85 15.60 14.42 14.56 15.92 15.01 14.58 13.42 16.32 14.19 13.51 12.64 15.57 16.34

10.98 9.67 8.87 9.59 7.99 8.36 8.58 9.61 7.94 8.56 9.78 9.04 10.23 8.94 9.06 10.25 6.99 10.20 10.54 9.64 11.10 8.22 9.47 9.01 9.47 8.09 9.33 10.76 9.15 9.74 9.74 10.78 9.30 8.78 10.10 9.85 8.53 7.07 10.74 10.32

Word # o f Freq. 1rr. 2.46 2.24 2.18 1.49 1.57 1.72 1.99 2.09 1.75 1.95 1.60 1.78 1.30 1.60 2.03 2.48 1.63 2.29 1.86 2.30 2.33 1.52 2.15 1.89 1.71 1.94 1.48 2.38 1.97 2.39 1.60 2.21 2.24 1.92 1.78 1.71 1.79 1.59 2.51 1.92

1 0 1 0 0 0 0 0 0 0 0 1 0 0 2 1 0 0 0 0 0 0 1 1 0 1 0 0 0 0 0 1 0 0 0 0 0 0 1 1

APPENDIX 5.1

145

REGULAR-HIGH

cainot mauton swaner blayer goblen thaber begrid chager bodule foamus fering nagred thager caleng hyrald siflet weraly loqren tasmer dormen t home K manelv lareny primet raplev petory yulper sarone ramine surtel shread pimsel snigel prased sarted trames vartle sartil drunet

triwen

ACC

RT

%

msec

82 70 81 81 81 78 78 86 77 74 83 83 72 77 69 72 81 79 77 87 87 87 79 81 88 89 74 83 82 82 79 81 81 87 91 80 79 70 81 72

645 620 615 666 638 6 37 640 673 673 670 617 659 612 659 677 640 649 604 648 625 654 639 656 629 634 645 662 635 605 610 675 641 604 639 622 582 638 672 636 672

Rating

6.5 7.5 7.6 8.0 8.6 7.6 7.8 8.3 8.0 7.3 7.7 7.0 7.7 5.6 6.6 7.7 5.7 7.4 7.3 8.2 7.3 8.4 7.2 8.0 7.7 7.3 8.0 7.8 8.2 7.3 9.2 7.7 6.8 8.4 8.4 8.3 7.2 7.3 6.8 6.6

Single Letter

Biqram T r i g r a m

22.69 22.49 22.25 21.79 21.94 22.42 22.27 22.90 22.78 21.80 23.22 22.66 22.70 22.85 21.84 23.06 22.87 22.53 22.92 22.92 22.68 22.96 23.15 22.64 22.49 23.13 21.17 23.83 23.29 23.43 23.19 22.48 22.42 23.18 24.44 22.80 22.95 22.85 22.49 21.90

13.74 13.54 13.40 13.78 13.35 14.95 12.89 15.27 13.92 10.39 15.85 13.74 15.29 15.50 9.21 12.69 13.87 12.07 13.94 14.56 15.54 15.33 14.18 13.97 11.86 14.12 10.87 14.63 14.84 14.64 13.92 11.77 12.58 15.33 16.02 14.11 15.01 12.89 13.05 11.54

4.38 2.28 5.50 8.14 3.60 5.14 3.96 7.54 2.63 0.00 9.73 4.75 6.39 6.17 3.10 5.33 3.36 3.89 3.87 6.00 8.41 8.76 5.68 4.78 2.62 5.36 5.09 6.14 8.42 5.23 7.94 2.36 1.34 6.16 6.87 7.74 8.74 3.90 2.81 1.90

Word FKeq. 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

# of IKK.

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 1 0 0 1 0 1 0 0 1 0 1 1 0 0

CHAPTER 5

146

REGULAR-LOW AC C

%

onicat otanum erswan byeral glenob therab gredib greach edolub osafum grefin gredan greath glecan hydra1 flesit lyeraw gleron steram drenom therom lyeman nyelar trepim lyerap tyerop ryelup erosan amerin tresul dreash emslip glesin dresap dresat tresam treval trisal tredun trewin

71 59 71 77 79 75 66 68 68 53 81 85 83 81 72 71 73 80 79 75 80 66 77 73 75 72 73 73 77 74 73' 73 71 75 87 76 84 71 72 79

RT R a t i n g msec 637 668 675 667 660 666 672 648 679 669 633 653 601 648 654 621 690 621 626 627 658 693 656 645 702 647 684 621 638 636 686 638 632 652 647 635 663 608 641 651

6.5 6.9 6.0 4.8 7.3 7.0 5.9 8.7 5.3 4.4 7.0 7.0 8.1 6.5 7.6 7.6 6.8 8.0 7.6 7.1 7.6 8.1 5.3 7.2 5.9 5.3 6.1 6.9 7.0 6.9 7.9 6.7 7.1 6.8 6.3 7.0 8.1 7.1 7.7 7.3

Single Letter

Bigram T r i q r a m

Word # o f Freq. Irr.

20.84 20.12 21.01 20.60 19.23 19.48 18.96 21.03 17.97 18.41 20.20 21.13 21.00 20.67 19.92 21.38 19.87 21.27 21.21 21.10 21.07 20.53 20.64 20.67 19.08 19.29 18.59 21.72 20.78 20.74 21.211 18.97 20.90 19.73 21.54 20.79 20.78 21.33 20.99 20.91

10.31 12.46 8.35 8.29 9.63 9.68 10.13 13.62 4.79 5.98 12.27 13.02 13.66 10.86 6.68 11.58 6.87 12.32 11.08 12.93 12.72 9.64 7.45 10.67 6.47 7.49 4.56 11.75 11.53 11.28 12.29 6.56 11.50 9.52 11.21 11.26 11.91 13.45 9.29 10.96

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

0.60 2.65 0.00 1.20 1.74 3.39 5.34 5.69 0.00 0.00 4.80 4.13 8.11 0.00 1.20 1.00 0.00 2.12 2.84 3.93 3.39 2.16 1.95 1.74 0.00 0.00 0.00 1.08 1.26 2.22 6.56 1.32 2.71 2.48 2.48 2.52 1.74 4.13 3.55 2.34

0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 1 0 1 1 1 0 0 0 0 1 0 0 0 0 0 0 0 0

APPENDIX 5.1

147

IRREGULAR-HIGH

aiocnt auotnm wnraes lbraey lnboeg bhrtea ierbgd ahcger leoubd uaomf s rfnieg arnged hrtaeg lcnaeq yrahld t l f ies rwlaey glnoer mrtaes oermnd mroteh lmnaey lrnaey tmriep plraey yptoer lpyuer snaoer mraien lrtues srdaeh ilmpes ilgnes prsaed srtaed mtraes avrlet iastlr rdnuet wrntei

Acc

RT

%

msec

63 69 70 81 65 75 66 71 76 61 70 84 70 67 61 68 73 78 76 71 82 70 69 68 84 70 68 75 75 71 67 74 68 85 86 72 74 81 75 63

656 652 666 699 692 664 728 674 691 698 656 663 663 675 681 664 688 662 657 650 660 705 648 662 573 692 671 645 612 656 680 635 658 623 675 647 656 650 712 696

Rating

3.1 3.7 2.4 3.0 2.1 1.5 2.3 3.0 2.5 2.0 2.2 3.8 2.3 2.2 2.4 2.6 2.1 2.9 2.3 2.8 2.8 2.6 2.8 2.7 2.9 2.6 3.0 4.3 3.4 2.0 2.1 3.8 4.5 3.3 2.2 2.3 4.4 2.6 2.1 2.4

Single Letter

Biqram T r i g r a m

22.36 22.07 22.93 21.76 21.87 22.22 21.96 22.64 21.38 20.03 22.21 22.98 22.50 22.06 21.14 22.89 21.52 22.42 23.27 22.62 22.84 21.74 22.70 20.72 22.96 21.13 21.70 23.41 23.27 23.34 22.36 22.08 22.00 23.25 23.75 23.20 21.71 22.67 21.74 20.67

7.20 5.49 8.58 7.90 4.07 9.43 5.31 5.86 10.15 3.61 5.60 14.28 5.98 3.46 9.17 10.79 6.14 9.15 9.56 10.37 8.68 5.91 7.39 7.81 8.90 8.56 6.44 5.96 11.40 11.26 4.32 11.74 8.80 9.44 9.92 10.13 10.12 9.07 7.91 11.47

0.00 1.49 1.18 1.18 0.60 1.59 1.32 2.73 0.00 0.00 1.83 6.08 0.00 0.00 1.34 3.30 0.00 0.00 0.00 2.30 2.53 0.00 0.00 2.31 1.18 0.70 0.00 1.56 1.97 2.42 0.00 3.47 3.72 0.00 0.00 2.82 3.63 4.33 0.00 2.76

Word # o f FKeq. i K K . 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.a0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

2 3 3 2 3 4 3 2 2 4 2 1 3 3 2 2 3 2 3 3 2 3 3 2 2 3 2 2 2 2 4 2 2 2 3 2 2 3 2 3

CHAPTER 5

148

IRREGULAR-LOW AC c

%

icntoa nmtaou rnwesa rbleya ebgnlo rtbeha ebrgd i hreagc obdeul ofmsua efnqri ednrga grheta eclnqa rdlhya eflsti eyrlwa egnrlo emrtsa rmedno hretmo emnyla enyrla rtpeim epylra ervtpo erplvu rnseoa rniema elsrtu hsreda lsepmi nglesi dsepra dtsera esrtma tlerav irltsa edtrnu

62 55 65 67 69 72 58 68 73 62 71 67 77 65 53 66 67 67 66 71 69 73 78 67 70 71 66 63 69 71 75 69 65 82 77 74 67 70 71

RT R a t i n g msec 683 707 704 728 670 736 697 646 692 710 697 698 655 7 38 743 707 707 655 629 644 633 695 677 652 670 6 59 666 648 656 664 656 672 662 665 668 681 680 655 656

2.0 2.1 2.2 2.4 2.7 2.8 2.0 2.4 4.6 2.5 2.1 2.4 3.2 2.6 1.8 2.7 2.8 2.9 2.3 3.1 2.4 4.5 3.0 2.4 3.1 3.2 2.8 2.4 2.3 2.2 2.4 2.8 2.4 3.6 2.4 3.4 2.4 2.8 2.1

Word # o f Freq. Irr.

Single Letter 20.38 19.06 20.26 18.96 19.04 19.78 18.09 20.49 19.15 18.80 18.98 19.25 20.07 20.09 18.53 18.72 18.53 19.24 20.19 19.48 19.84 19.05 20.20 20.65 19.56 19.23 18.37 21.08 20.44 19.52 19.90 18.23 18.25 19.81 21.03 20.06 17.70 20.53 19.12

6.29 2.62 6.02 2.98 5.08 3.45 4.46 7.66 8.15 6.02 6.80 6.05 9.11 5.10 0.00 7.60 4.09 6.11 4.25 3.88 5.25 4.15 8.91 4.62 3.29 5.59 3.54 5.96 8.26 4.51 7.92 4.49 5.28 5.25 10.08 7.24 6.34 3.39 4.93

0.48 0.00 1.45 0.00 0.00 0.00 0.00 2.37 0.00 0.00 1.36 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.03 0.00 0.00 0.00 0.00 0.00 0.00 1.51 0.48 0.00 0.70 0.00 2.00 0.00 5.92 0.00 1.28 0.00 0.00

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 c1.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

3 4 3 2 4 3 3 2 1 3 3 4 2 2 4 2 4 4 4 3 3 2 2 2 2 2 2 4 2 4 3 3 2 2 3 4 2 4 3

APPENDIX 5 . 2

149

A p p e n d i x 5.2 S i n g l e - L e t t e r P o s i t i o n a l F r e q u e n c i e s (Token Counts) A c c o r d i n g t o S e r i a l P o s i t i o n and Word L e n g t h f o r Words 3 t o 7 L e t t e r s i n Length. I n s t r u c t i o n s f o r Using Frequency T a b l e s The w o r d s u s e d t o o b t a i n t h e s i n g l e - l e t t e r frequencies came from t h e K u c e r a and F r a n c i s ( 1 9 6 7 ) word c o u n t . Words wh i ch had a K u c e r a and F r a n c i s c o u n t o f a t l e a s t t h r e e an d wh i ch a p p e a r e d i n a t l e a s t t h r e e d i f f e r e n t s a m p l e d t e x t s were selected. T h ey were t h e n s e p a r a t e d f o r e a c h word l e n g t h . T h e s e c o u n t s were m u l t i p l i e d b y t h e f r e q u e n c y o f e a c h o f t h e wo r d s s o t h a t t h e s i n g l e - l e t t e r f r e q u e n c i e s o f t h e t a b l e s a r e based on t o k e n r a t h e r t h a n t y p e c o u n t s (see C h a p t e r 1 ) . This s e l e c t i o n p r o c e d u r e y i e l d e d t h e f o l l o w i n g number o f word t o k e n s f o r e a c h word l e n g t h : 2 1 0 9 9 0 , 1 5 3 3 1 5 , 1 0 2 6 9 9 , 7 6 2 9 5 , 68894 f o r 3 t h r o u g h 7 l e t t e r words, r e s p e c t i v e l y . The number o f t i m e s e a c h l e t t e r o f t h e a l p h a b e t o c c u r r e d These i n e a c h l e t t e r p o s i t i o n o f t h e w o r d s was c o u n t e d . t o t a l s , along with t h e i r sum, are presented i n t h e t a b l e s a s t h e f i r s t row o f n u m b e r s f o r e a c h l e t t e r . T h u s , f o r e x a m p l e , f o r s i x - l e t t e r words, t h e l e t t e r 5 occurred i n t h e s i x t h l e t t e r p o s i t i o n 2 3 1 t i m e s and o c c u r r e d i n a l l p o s i t i o n s a t o t a l o f 3 , 8 0 4 t i m e s . Below e a c h o f t h e f r e q u e n c i e s i s t h e b a s e 10 logarithm of the frequency count. I t s h o u l d b e n o t e d t h a t f o r some s i n g l e l e t t e r s , the f r e q u e n c y o f o c c u r r e n c e is z e r o i n some p o s i t i o n s . The l o g a r i t h m o f z e r o is u n d e f i n e d , b u t f o r t h e p u r p o s e s o f t h e t a b l e s was s e t e q u a l t o z e r o .

150

CHAPTER 5

S I N G L E L E T T E R F R E Q U E N C I E S F O R WORDS OF L E T T E R LENGTH 3 LETTER POSITION 2ND 3RD 1ST A

B C D E

F G

H I J K

L

M

39519 4.597 5902 3.771 2466 3.392 2301 3.362 760 2.881 10988 4.041 1967 3.294 21515 4.333 2009 3.303 515 2.712 182 2.260 1604 3.205 4180 3.621

28085 4.448 3 .477 379 2.579 142 2.152 11050 4.043 644 2.809 498 2.697 75511 4.878 13084 4.117 0 0.000 62 1.792 3766 3.576 15 1.176

221 2.344 364 2.561 186 2.270 37652 4.576 82860 4.918 639 2.806 790 2.898 16 1.204 7 .845 0 0.000 150 2.176 3192 3.504 3108 3.492

SUM

67825 4.831 6269 3.797 3031 3.482 40095 4.603 94670 4.976 12271 4.089 3255 3.513 97042 4.987 15100 4.179 515 2.712 394 2.595 8562 3.933 7303 3.864

A P P E N D I X 5.2 S I N G L E L E T T E R F R E Q U E N C I E S F O R WORDS O F L E T T E R L E N G T H 3 LETTER P O S I T I O N 3RD 1ST 2ND N

0 P

Q R

s T

U V W

X

Y

z

7865 3.896 8900 3.949 1227 3.089 11 1.041 864 2.937 6354 3.803 73207 4.865 592 2.772 93 1.968 14079 4.149 0 0.000 3855 3.586 35 1.544

33973 4.531 23643 4.374 27 1.431 0 0.000 5591 3.747 736 2.867 1937 3.287 9472 3.976 41 1.613 2199 3.342 6 .778 126 2.100 0 0.000

6169 3.790 4829 3.684 474 2.676 0 0.000 16036 4.205 22017 4.343 16145 4.208 3307 3.519 73 1.863 5380 3.731 671 2.827 6704 3.825 0 0.000

SUM

48007 4.681 37372 4.573 1728 3.238 11 1.041 22491 4.352 29107 4.464 91289 4.960 13371 4.126 207 2.316 21658 4.336 677 2.831 111685 4.029 35 1.544

151

152

CHAPTER 5

SINGLE LETTER FREQUENCIES FOR WORDS OF LETTER LENGTH 4 LETTER POSITION 2N D 1ST 3RD A

B C D

E

F G H I J

K L

M

3077 3.488 7266 3.861 4530 3.656 4614 3.664 3714 3.570 10556 4.023 3091 3.490 9784 3.991 2191 3.341 2051 3.312 2252 3.353 7898 3.898 10777 4.032

26766 4.428 244 2.387 90 1.954 393 2.594 20802 4.318 0 0.000 128 2.107 29988 4.477 22145 4.345 0 0.000 85 1.929 2843 3.454 50 1.699

20259 4.307 253 2.403 6697 3.826 2462 3.391 21789 4.338 1648 3.215 1169 3.068 376 2.575 9661 3.985 0 0.000 3066 3.487 11225 4.050 6902 3.839

4TH

SUM

953 2.979 301 2.479 54 1.732 10129 4.006 32881 4.517 528 2.723 1351 3.131 12322 4.091 35 1.544 0 0.000 5572 3.746 7346 3.866

51055 4.708 8064 3.907 11371 4.056 17598 4.245 79186 4.899 12724 4.105 5739 3.759 52470 4.720 34032 4.532 2051 3.312 10975 4.040 29312 4.467 26102 4.417

8373 3.923

APPENDIX 5 . 2

153

SINGLE LETTER FREQUENCIES FOR WORDS OF LETTER LENGTH 4 LETTER POSITION 1ST 2N D 3RD N

0 P

Q R S

T

2119 3.326 4261 3.630 3518 3.546 15 1.176 3075 3.488 10815 4.034 30636 4.486

U

1340 3.127

V

1308 3.117 22367 4.350 0 0.000 1996 3.300 64 1.806

W X

Y 2

4TH

SUM 30393 4.483 42273 4.626 7251 3.860 18 1.255 28522 4.455 33145 4.520 68344 4.835 11171 4.048

5753 3.760 24056 4.381 978 2.990 0 0.000 6514 3.814 742 2.870 563 2.751 7042 3.848 2843 3.454 555 2.744 62 1.792 673 2.828

8265 3.917 10798 4.033 1040 3.017 0 0.000 13598 4.133 10091 4.004 12251 4.088 2751 3.439 5723 3.758 1526 3.184 470 2.672 998 2.999

14256 4.154 3158 3.499 1 7 15 3.234 3 .477 5335 3.727 11497 4.061 24894 4.396 38 1.580 0 0.000 2163 3.335 77 1.886 10214 4.009

9874 3.994 2661 1 4.425 609 2.785 13881 4.142

0 0.000

305 2.484

120 2.079

489 2.689

154

CHAPTER 5

SINGLE LETTER FREQUENCIES FOR WORDS OF LETTER LENGTH 5

A

B C D E

F G H I

J

K L M

LETTER POSITION 2ND 1ST 3RD

4TH

5TH

SUM

12306 4.090 826 2.917 938 2.972 2681 3.428 1484 5 4.172 314 2.497 3796 3.579 1740 3.241 13572 4.133 291 2.464 1182 3.073 2801 3.447 2103 3.323

5563 3.745 4 38 2.641 8332 3.921 2860 3.456 18479 4.267 447 2.650 1475 3.169 2465 3.392 683 2 3.835 0 0.000 1242 3.094 11708 4.068 1641 3.215

523 2.719 36 1.556 582 2.765 11845 4.074 21152 4.325 493 2.693 3349 3.525 7039 3.848 75 1.875 0 0.000 2195 3.341 4948 3.694 404 2.606

36206 4.559 8715 3.940 16824 4.226 20390 4.309 66374 4.822 8386 3.924 12885 4.110 33400 4.524

7359 3.867 5264 3.721 6416 3.807 2379 3.376 2189 3.340 5614 3.749 3565 3.552 3348 3.525 917 2.962 525 2.720 618 2.791 4187 3.622 4220 3.625

10455 4.019 2151 3.333 556 2.745 625 2.796 9709 3.987 1518 3.181 700 2.845 18808 4.274 9821 3.992 0 0.000 85 1.929 4783 3.680 1357 3.133

31217 4.494 816 2.912 5322 3.726 28427 4.454 9725 3.988

APPENDIX 5 . 2

155

SINGLE LETTER FREQUENCIES F O R WORDS OF LETTER LENGTH 5 LETTER POSITION 1ST 2ND 3RD N

0

P Q R

S T U V W

X

Y 2

2336 3.368 3064 3.486 4418 3.645

4TH

5TH

SUM 23397 4.369 35303 4.548 8345 3.921 6 30 2.799 40444 4.607 37771 4 * 577 41678 4.620 17521 4.244 5852 3.767 15587 4.193 681 2.833 7370 3.867 229 2.360

4331 3.637 10612 4.026 1046 3.020 0 0.000 8523 3.931 2106 3.323 4727 3.675 9278 3.967 2979 3.474 755 2.878 364 2.561 4 57 2.660

8513 3.930 2682 3.428 879 2.944 0 0.000 9276 3.967 8108 3.909 6054 3.782

2038 3.309 938 2.972 12634 4.102 0 0.000 1547 3.189

2899 3.462 18464 4.266 1255 3.099 115 2.061 7818 3.893 959 2.982 5756 3.760 3058 3.485 687 2.837 682 2.834 151 2.179 287 2.458

3139 3.497 1239 3.093 1121 3.050 7 .845 102 2.009

5318 3.726 4 81 2.682 747 2.873 0 0.000 11791 4.072 15072 4.178 11098 4.045 8 .90 3 9 .954 395 2.597 159 2.201 4977 3.697

3 .477

0 0.000

126 2.100

97 1.987

3 .477

515 2.712 3036 3.482 11526 4.062 14043 4.147

156

CHAPTER 5

SINGLE LETTER FREQUENCIES FOR WORDS OF LETTER LENGTH 6 LETTER POSITION 2ND 3RD 1ST A

B C D E

F G H I

J K

L M

5529 3.743 5116 3.709 6237 3.795 3146 3.498 3313 3.520 3953 3 * 597 1712 3.234 2310 3.364 1668 3.222 541 2.733 225 2.352 3918 3.593 4718 3.674

11057 4.044 284 2.453 1753 3.244 294 2.468 14308 4.156 90 3 2.956 211 2.324 4498 3.653 7396 3.869 0 0.000 73 1.863 3028 3.481 548 2.739

6081 3.784 1102 3.042 3765 3.576 1648 3.217 3548 3.550 2424 3.385 1746 3.242 1292 3.111 4374 3.641 140 2.146 732 2.855 4417 3.645 3912 3.592

4TH

5TH

6TH

SUM

4226 3.626 1286 3.109 1494 3.174 2638 3.421 7619 3.882 347 2.540 2500 3.398 2784 3.445 10676 4.828 0 0.000 2002 3.301 3448 3.538 2143 3.331

3257 3.513 79 1.898 3384 3.529 1284 3.109 23111 4.364 57 1.756 2425 3.385 1096 3.040 2909 3.464

449 2.652 40 1.602 743 2.871 13473 4.129 12471 4.096 593 2.773 3784 3.578

30599 4.486 7907 3.898 17376 4.240 22483 4.352 64370 4.809 8277 3.918 12378 4.093 14511 4.162 27068 4.432 681 2.833 3804 3.580 26303 4.420 13598 4.133

B 0.000 541 2.733 8721 3.941 1297 3.113

2531 3.403 45 1.653 0 0.000 231 2.364 2771 3.443 980 2.991

APPENDIX 5 . 2

157

SINGLE LETTER FREQUENCIES FOR WORDS OF LETTER LENGTH 6

N

0

P

Q R S

T

U V W

X

Y

z

LETTER POSITION 3RD 1ST 2ND

4TH

5TH

6TH

SUM

3306 3.519 10986 4.041 1154 3.062 166 2.220 4923 3.692 862 2.936 3427 3.535 5252 3.720

4535 3.657 6715 3.827 1398 3.146 91 1.959 9119 3.960 4710 3.673 7531 3.877 2800 3.447

4451 3.648 5925 3.773 2401 3.380 64 1.806 3680 3.566 2784 3.445 7658 3.884 5928 3.773

8005 3.903 5221 3.718 786 2.895 0 0.000 6188 3.792 2717 3.434 3149 3.498 1027 3.012

5286 3.723 172 2.236 109 2.037 0 0.000 8147 3.911 10904 4.038 6979 3.844 61 1.785

27626 4.441 30417 4.483 11675 4.067 391 2.592 36333 4.560 33400 4.524 32673 4.514 16147 4.208

183 2.262

1606 3.206 1382 3.141 154 2.188 999 3.000 74 1.869

984 2.993 772 2.888 13 1.114 3 50 2.544 122 2.086

364 2.561 110 2.041 3 .477 4 94 2.694 70 1.845

0 0.000 670 2.826 31 1.491 5825 3.765 0 0.000

4210 3.624 5887 3.770 911 2.960 8473 3.928 272 2.435

2043 3.310 1398 3.146 5827 3.765 70 1.845 4276 3.631 11423 4.058 3929 3.594 1079 3.033 1073 3.031 2645 3.422 0 0.000 140 2.146 6 .778

308 2.489 710 2.851 665 2.823 0 0.000

158

CHAPTER 5

SINGLE LETTER FREQUENCIES FOR WORDS OF LETTER LENGTH 7 LETTER POSITION 1ST 2ND 3RD A

B C D E F G H

I J

K L

M

4796 3.681 4147 3.618 7268 3.861 2846 3.454 3068 3.487 3548 3.550 1982 3.297 3232 3.509 1268 3.103 471 2.673 532 2.726 1990 3.299 3649 3.562

6979 3.844 407 2.610 946 2.976 372 2.571 15655 4.195 623 2.794 663 2.822 3963 3.598 6571 3.818 0 0.000 48 1.681 2524 3.402

7353 3.866 690 2.839 3977 3.600 1168 3.067 4768 3.678 1162 3.065 1493 3.174 501 2.700 4053 3.608 167 2.223 69 1.839 3526 3.547

917 2.962

2923 3.466

4TH

5TH

6TH

7TH

SUM

4582 3.661 1357 3.133 2921 3.466 2263 3.355 6532 3.815 859 2.934 1564 3.194 2243 3.351

5253 3.720 611 2.786 1735 3.239 1202 3.080 10073 4.003 4 58 2.661 1803 3.256 2874 3.458 15115 4.179 0 0.000 524 2.719 3125 3.495

5036 3.702 85 1.929 2707 3.432 2059 3.314 16835 4.226 132 2.121 2323 3.366 1035 3.015 1735 3.239 0 0.000 137 2.137 4433 3.647

34566 4.539 7316 3.864 19909 4.299 18794 4.274 66037 4.820 7551 3.878 17043 4.232 15492 4.190

983 2.993

656 2.817

567 2.754 19 1.279 355 2.550 8884 3.949 9106 3.959 769 2.886 7215 3.858 1644 3.216 18 1.255 0 0.000 120 2.079 3830 3.583 1478 3.170

6031 3.780 2 54 2.405 1280 3.107 4545 3.658 1730 3.238

34791 4.541 892 2.950 2710 3.433 23973 4.380 12336 4.091

APPENDIX 5 . 2

159

SINGLE LETTER FREQUENCIES FOR WORDS OF LETTER LENGTH 7 LETTER POSITION 3RD 2N D 1ST N 0

e Q R

S T U V W

X Y 2

1628 3.212 1460 3.164 6067 3.783 358 2.554 3726 3.571 8092 3.908 3731 3.572 603 2.780 1043 3.018 3289 3.517 0 0.000 93 1.968 7 .845

3150 3.498 8667 3.938 1211 3.083 113 2.053 6991 3.845 558 2.747 1976 3.296 4693 3.671 386 2.587 161 2.207 954 2.980 366 2.563 0 0.000

5166 3.713 5792 3.763 2154 3.333 199 2.299 8487 3.929 4162 3.619 5538 3.743 2573 3.410 1421 3.153 764 2.883 314 2.497 392 2.593 82 1.914

4TH

5TH

6TH

7TH

SUM

3785 3.578 2962 3.472 2655 3.424 26 1.415 4046 3.607 4055 3.608 8755 3.942 3082 3.489 1442 3.159 1544 3.189 0 0.000 304 2.483 77 1.886

3401 3.532 5046 3.703 994 2.997 23 1.362 4791 3.680 1224 3.088 4215 3.625 3862 3.587 1106 3.044 269 2.430 31 1.491 116 2.064 60 1.778

11623 4.065 2700 3.431 576 2.760 0 0.000 6193 3.792 4233 3.627 3466 3.540 1840 3.265 629 2.799 2 54 2.405 38 1.580 66 1.820 103 2.013

4650 3.667 210 2.322 138 2.140 0 0.000 4948 3.694 12054 4.081 6324 3.801 3 .477 0 0.000 116 2.064 114 2.057 6332 3.802 0 0.000

33403 4.524 26837 4.429 13795 4.140 719 2.857 39182 4.593 34378 4.536 34005 4.532 16656 4.222 6027 3.780 6397 3.806 1451 3.162 7669 3.885 329 2.517

16 0

CHAPTER 5

A p p e n d ix 5 . 3 Bigram P o s i t i o n a l F r e q u e n c i e s ( T o k e n C o u n t s ) A c c o r d i n g t o S e r i a l P o s i t i o n and Word L e n g t h f o r Words 3 t o 7 Letters i n Length. I n s t r u c t i o n s f o r using frequency t a b l e s T h e s e c o u n t s were b a s e d o n t h e same word t o k e n s a s were the single-letter c o u n t s i n Appendix 5 . 2 . In t h i s case, h o w e v e r , e a c h word was b r o k e n down i n t o i t s b i g r a m c o m p o n e n t s (i.e., battle----> &, at, E, g , k)an d t h e f r e q u e n c y o f o c c u r r e n c e o f e a c h o f t h e b i g r a m s was t a b u l a t e d f o r e a c h word length. For example, f o r s i x - l e t t e r words, t h e bigram 9 o c c u r r e d a s t h e i n i t i a l bigram 1 8 5 times, a s t h e second bigram 160 times, a s t h e t h i r d bigram 148 times, e t c . N o t i c e t h a t 3 never o c c u r r e d a s t h e s i x t h bigram. Also n o t i c e t h a t t h e b i g r a m do n e v e r o c c u r r e d a t a l l . A b i g r a m w h i c h d i d n o t o c c u r a t l e a s t o n c e f o r w o r d s o f a g i v e n l e n g t h was o m i t t e d f r o m t h e listing in the tables. I t s h o u l d b e n o t e d t h a t f o r some b i g r a m s , t h e f r e q u e n c y o f The l o g a r i t h m o f z e r o i s o c c u r r e n c e is z e r o i n some p o s i t i o n s . u n d e f i n e d , b u t f o r t h e p u r p o s e s o f t h e t a b l e s was s e t e q u a l t o zero.

A P P E N D I X 5.2 BIGRAM F R E Q U E N C I E S F O R W O R D S OF LETTER L E N G T H 3 BIGRAM P O S I T I O N 1ST 2ND SUM AB

3 .477 298 2.474

12 1.079 0 0.000

15 1.176 298 2.474

AD

98 1.991

5378 3.731

5476 3.738

AF

5 .699

0 0.000

5 .699

AG

473 2.675 424 2.627

75 1.875 0 0.000

548 2.739

0 0.000

15 1.176

15 1.176

AL

3008 3.478

33 1.519

3041 3.483

AM

15 1.176

122 2.086

137 2.137

AN

30232 4.480

3316 3.521

33548 4.526

A0

0 0.000

24 1.380

24 1.380

AP

18 1.255

98 1.991

116 2.064

AR

4736 3.675

1324 3.122

6060 3.782

AS

144 2.158

12364 4.092

12508 4.097

AT

16 1.204

414 2.617

4 30 2.633

AU

25 1.398

0 0.000

25 1.398

AV

13 1.114

0 0.000

13 1.114

AW

5 .699

713 2.853

718 2.856

AX

6 .778

AY

B 0.000 348 2.542

226 2.354 3971 3.599

232 2.365 3971 3.599

' 0 0.000

348 2.542

AC

A1 AK

BA

424 2.627

161

162

CHAPTER 5

BIGRAM FREQUENCIES F O R WORDS OF LETTER LENGTH 3

B I G R A M POSITION 1ST 2ND SUM BE

BI BO

BU CA

CE

co CR CT CU

CY DA DD

DE DI DO DR

DS DU EA EB

194 2.288 492 2.692 367 2.565 4501 3.653 2108 3.324 0 0.000 73 1.863 48 1.681

0 0.000 0 0.000 0 0.000 0 0.000 60 1.778 0 0.000 0 0.000

197 2.294 492 2.692 367 2.565 4501 3.653 2108 3.324 60 1.778 13 1.863 48 1.681

0 0.000 237 2.375 0 0.000 740 2.869

307 2.487 0 0.000 12 1.079 0 0.000

3 07 2.487 2 37 2.375 12 1.079 740 2.869

0 0.000 44 1.643 1152 3.061 135 2.130 73 1.863 0 0.000

132 2.121 0 0.000 0 0.000 0 0.000 0 0.000 10 1.000 0 0.000 126 2.100 26 1.415

132 2.121 44 1.643 1152 3.061 135 2.130 73 1.863 10 1.000 157 2.196 216 2.334 26 1.415

157 2.196 90 1.954 0 0.000

.h 7 73

A P P E N D I X 5.2 B I G R A M F R E Q U E N C I E S F O R WORDS O F L E T T E R LENGTH 3 BIGRAM P O S I T I O N 1ST 2ND SUM EC

0 0.000

36 1.556

36 1.556

ED

0 0.000

513 2.710

513 2.710

EE

0 0.000

845 2.927

845 2.927

EG

25 1.398

69 1.839

94 1.973

EI

0 0.000

7 .845

7 .845

EL

3 .477

16 1.204

19 1.279

EM

0 0.000

8 ,903

8 .903

EN

410 2.613

1083 3.035

1493 3.174

EO

0 0.000

7 .845

7 .845

EP

0 0.000

13 1.114

13 1.114

ER

30 1.477

3408 3.532

3438 3.536

ES

3 .471

155 2.190

158 2.199

ET

58 1.763

2243 3.351

2301 3.362

EV

19 1.279

33 1.519

52 1.716

EW

0 0.000

2262 3.354

2262 3.354

0 0.000

97 1.987

97 1.981

EY

122 2.086

103 2.013

225 2.352

FA

505 2.703

0 0.000

505 2.703

FE

679 2.832

679 2.832

FF

0 0.000

0 0.000 639 2.805

FI

161 2.207

0 0.000

161 2.207

EX

639 2.806

163

164

CHAPTER 5

B I G R A M F R E Q U E N C I E S F O R WORDS O F L E T T E R L E N G T H 3 BIGRAM P O S I T I O N 2ND 1ST SUM

FL

51 1.708

0 0.000

51 1.708

FO

9535 3.979

0 0.000

9535 3.979

FT

0 0.000

5 .699

5 .699

FU

57 1.756

0 0.000

57 1.756

GA

154 2.188 781 2.893

0 0.000 2 27 2.356

154 2.188

GG

0 0.000

12 1.079

12 1.079

GI

27 1.431

0 0.000

27 1.431

GO

819 2.913

259 2.413

1078 3.033

GU

186 2.270

0 0.000

HA

7694 3.886

0 0.000

186 2.270 7694 3.886

HE

3078 3.488

72830 4.862

75908 4.880

HI

9747 3.989

0 0.000

9747 3.989

HO

970 2.987

2252 3.353

HU

26 1.415

0 0.000

3222 3.508 26 1.415

HY

0 0.000

429 2.632

4 29 2.632

IA

0 0.000

48 1.681

48 1.681

IC

57 1.756

8 .903

65 1.813

ID

0 0.000

1301 3.114

1301 3.114

IE

0 0.000 0 0.000

169 2.228

169 2.228

455 2.658

455 2.658

GE

IG

1008 3.003

A P P E N D I X 5.2 BIGRAM FREQUENCIES F O R W O R D S OF LETTER LENGTH 3 BIGRAM POSITION 2ND SUM 1ST IK

4 .602

0 0.000

IL

39 1.591

93 1.968

4 .602 132 2.121

IM

0 0.000

2741 3.438

2741 3.438

IN

36 1.556

168 2.225

204 2.310

I0

6 .778 0 0.000

4 .602

10 1.000

88 1.944

88 1.944

IR

0 0.000

352 2,547

352 2.547

IS

0 0.000

6997 3.845

6997 3.845

IT

1858 3.269

413 2.616

2271 3.356

IV

9 .954

0 0.000

9 .954

IX

0 0.000

247 2.393

247 2.393

JA

77 1.886

0 0.000

77 1.886

JE

63 1.799

0 0.000

63 1.799

JI

36 1.556

0 0.000

36 1.556

JO

333 2.522 6 .778

0 0.000

333 2.522

0 0.000

6 .778

KA

21 1.322

0 0.000

21 1.322

KE

100 2.000

4 .602

1fl4 2.017

KI

61 1.785

0 0.000

61 1.785

KY

0 0.000 491 2.691

58 1.763 17 1.230

58 1.763

IP

JU

LA

508 2.706

165

CHAPTER 5

166

BIGRAM F R E Q U E N C I E S F O R WORDS OF L E T T E R LENGTH 3 BIGRAM P O S I T I O N 1ST 2ND SUM LD

0 0.000

660 2.820

660 2.820

LE

618 2.791

0 0.000

618 2.791

LI

113 2.053

0 0.000

113 2.053

LL

0 0.000

3040 3.483

3040 3.483

LM

0 0.000

3 .411

3 .417

LO

377 2.576

0 0.000

377 2.576

LT

5 .699

0 0.000

5 .699

LU

0 0.000

8 .903

8 .903

LY

0 0.000

38 1.580

38 1.580

MA

2690 3.430

0 0.000

2690 3.430

ME

895 2.952

0 0.000

895 2.952

MI

13 1.114

0 0.000

13 1.114

MO

16 1.204

0 0.000

16 1.204

MR

534 2.728

0 0.000

534 2.728

MU

32 1.505

0 0.000

32 1.505

MY

0 0.000 17 1.230,

15 1.176

15 1.176

0 0.000

17 1.230

NC

0 0.000

20 1.301

20 1.301

ND

0 0.000

29265 4.466

29265 4.466

NE

1669 3.222

3292 3.517

4961 3.696

NI

3 ,477

0 0.000

3 .477

NA

APPENDIX 5.2 BIGRAM FREQUENCIES F O R W O R D S OF LETTER L E N G T H 3 BIGRAM POSITION 2ND SUM 1ST NK

0 0.000

7 .845

7 .845

NN

0 0.000

38 1.580

38 1.580

NO

6161 3.790

0 0.000

6161 3.790

NT

0 0.000

6 .778

6 .778

NU

15 1.176 0 0.000

0 0.000 1345 3.129

15 1.176

OA

15 1.176

0 0.000

15 1.176

OB

0 0.000

307 2.487

3 07 2.487

oc

24 1.380

23 1.362

47 1.672

OD

44 1.643

357 2.553

401 2.603

OE

0 0.000

81 1.908

81 1.908

OF

639 2.806

0 0.000

639 2.806

OG

0 0.000

114 2.057

114 2.057

01

93 1.968

0 0.000

93 1.968

OL

660 2.820

10 1.000

670 2.826

OM

0 0.000

ON

3292 3.517

66 1.820 306 2.486

66 1.820 3598 3.556

00

0 0.000

a44 2.926

844 2.926

OP

0 0.000 3 .477

230 2.362 9684 3.986

230 2.362 9687 3.986

0 0.000

52 1.716

52 1.716

NY

OR 0s

1345 3.129

167

CHAPTER 5

168

B I G R A M F R E Q U E N C I E S FOR WORDS OF LETTER L E N G T H 3 BIGRAM POSITION 1ST 2ND SUM OT

0 0.000

5397 3.732

3348 3.525

3299 3.518

5397 3.732 6647 3.823

0 0.000

40 1.602

40 1.602

782 2.893

2405 3.381

3187 3.503

0 0.000

101 2.004

101 2.004

OY

0 0.000

327 2.515

3 27 2.515

PA

253 2.403

0 0.000

253 2.403

PE

400 2.602

3 .477

403 2.605

PI

75 1.875

0 0.000

75 1.875

PO

40 1.602

0 0.000

40 1.602

PR

22 1.342

0 0.000

22 1.342

PT

0 0.000

15 1.176

15 1.176

PU

437 2.640

0 0.000

437 2.640

PY

0 0.000

9 .954

9 .954

QU

11 1.041

0 0.000

11 1.041

RA

212 2.326

30 1.477

242 2.384

RC

0 0.000

41 1.613

41 1.613

RE

248 2.394

4396 3.643

4644 3.667

RI

39 1.591

0 0.000

39 1.591

RM

0 0.000

94 1.973

RO

121 2.083

16 1.204

94 1.973 137 2.137

ou ov OW

ox

APPENDIX 5.2 BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 3 BIGRAM POSITION 1ST 2N D SUM RS

0 0.000

539 2.732

5 39 2.732

RT

0 0.000

208 2.318

208 2.318

RU

240 2.380

0 0.000

240 2.380

RY

4 .602

267 2.427

271 2.433

SA

1194 3.077

0 0.000

1194 3.077

SE

1414 3.150 2872 3.458

589 2.770

2003 3.302

11 1.041

2883 3.460

SI

439 2.642

0 0.000

439 2.642

SK

58 1.763

128 2.107

186 2.270

SL

5 .699

0 0.000

5 .699

SO

185 2.267

0 0.000

185 2.267

SP

9 .954

0 0.000

9 -954

ss

0 0.000

5 .699

5 .699

ST

0 0.000

3 .477

3 .477

SU

178 2.250

0 0.000

178 2.250

TA

241 2.382

0 0.000

241 2.382

TC

0 0.000

58 1.763

58 1.763

TD

0 0.000

5 .699

5 .699

TE

208 2.318 69983 4.845

16 1.204 0 0.000

224 2.350 69983 4.845

82 1.914

0 0.000

82 1.914

sn

TH TI

169

170

CHAPTER 5

BIGRAM F R E Q U E N C I E S F O R WORDS O F L E T T E R LENGTH 3 BIGRAM P O S I T I O N 2N D 1ST SUM TO TR TS

TU

TW UB UD UE UG UH

UM UN

uo UP

UR US

UT UY VA VE VI

1125 3.051 140 2.146 0 0.000 16 1.204 1412 3.150 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 3 .477 0 0.000 0 0.000 0 0.000 589 2.770 0 0.000 0 0 * 000 32 1.505 0 0.000 52 1.716

0 0.000 0 0.000 1858 3.269 0 0.000 0 0.000 19 1.279 41 1.613 166 2.220 65 1.813 5 ,699 74 1.869 486 2.687 11 1.041 45 1.653 1268 103 37 568 134 853 121 083 0 0.000 32 1.505 0 0.000

1125 3.051 140 2.146 1858 3.269 16 1.204 1412 3.150 19 1.279 41 1.613 166 2.220 65 1.813 5 .699 74 1.869 489 2.689 11 1.041 45 1.653 1268 3.103 626 2.797 7134 3.853 121 2.083 32 1.505 32 1.505 52 1.716

A P P E N D I X 5.2 BIGRAM FREQUENCIES F O R W O R D S OF LETTER LENGTH 3 BIGRAM P O S I T I O N 1ST 2ND SUM

vo

9 .954 0 0.000

0 0.000 9 .954

9 .954 9 .954

WA

11203 4.049

0 0.000

11203 4.049

WE

64 1.806

15 1.176

79 1.898

WH

2656 3.424 75 1.875

0 0.000 0 0.000

2656 3.424

0 0.000

772 2.888

772 2.888

76 1.881

1412 3.150

1488 3.173

WR

5 .699

0 0.000

5 .699

XE

0 0.000

6 .778

6 .778

YE

569 2.755

126 2.100

695 2.842

YO

3286 3.517

0 0.000

3286 3.517

ZE

26 1.415

0 0.000

26 1.415

9 .954

0 0.000

9 .954

VY

WI WN

wo

zo

75 1.875

171

172

CHAPTER 5

BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4 BIGRAM POSITION 1ST 2ND 3RD AB AC

AD AF AG AH A1 AK AL AM

AN A0 AP AQ AR AS

AT AU AV AW AX

236 2.373 65 1.813 54 1.732 0 0.000 69 1.839 0 0.000 62 1.792 10 1.000 1127 3.052 33 1.519 98 1.991 0 0.000 4 .602 0 0.000 660 2.820 62 1.792 47 1.672 44 1.643 0 0.000 461 2.664 45 1.653

70 1.845 3085 3.489 1210 3.083 82 1.914 178 2.250 0 0.000 3156 3.499 1569 3.196 1667 3.222 1958 3.292 2519 3.401 64 1.806 124 2.093 0 0.000 2197 3.342 2345 3.370 988 2.995 51 1.708 4415 3.645 158 2.199 16 1.204

33 1.519 0 0.000 1191 3.076 28 1.447 39 1.591 31 1.491 0 0.000 55 1.740 593 2.773 231 2.364 2390 3.378 0 0.000 95 1.978 3 .477 1427 3.154 52 1.716 13013 4.114 0 0.000 0 0.000 74 1.869 0 0.000

SUM 339 2.530 3150 3.498 2455 3.390 110 2.041 286 2.456 31 1.491 3218 3.508 1634 3.213 3381 3.530 2222 3.347 5007 3.700 64 1.806 223 2.348 3 .477 4284 3.632 2459 3.391 14048 4.148 95 1.978 4415 3.645 693 2.841 61 ~1.785

A P P E N D I X 5.2 BIGRAM F R E Q U E N C I E S F O R W O R D S OF LETTER LENGTH 4 BIGRAM P O S I T I O N 2ND 1ST 3RD

SUM

AY

0 0.000

763 2.883

1004 3.002

1767 3.247

AZ

0 0.000

151 2.179

0 0.000

151 2.179

BA

1579 3.198

0 0.000

47 1.672

1626 3.211

BE

3186 3.503

28 1.447

48 1.681

3262 3.513

BI

214 2.330

0 0.000

0 0.000

214 2.330

BL

217 2.336

216 2.334

0 0.000

433 2.636

BO

1803 3.256

0 0.000

0 0.000

1803 3.256

BR

14 1.146

0 0.000

0 0.000

14 1.146

BS

0 0.000

83 1.919

83 1.919

BT

0 0.000

0 0.000 0 0.000

13 1.114

13 1.114

BU

244 2.387

0 0.000

0 0.000

244 2.387

BY

9 .954

0 0.000

62 1.792

71 1.851

CA

1837 3.264

15 1.176

0 0.000

1852 3.268

CE

223 2.348

0 0.000

1196 3.078

1419 3.152

CH

73 1.863

14 1.146

3267 3.514

CI

400 2.602

13 1.114

0 0.000

3354 3.526 413 2.616

CK

0 0.000

0 0.000

1706 3.232

1706 3.232

CL

279 2.446

0 0.000

0 0.000

279 2.446

CO

1514 3.180

0 0.000

21 1.322

1535 3.186

CR

56 1.748

9 .954

0 0.000

65 1.813

CT

0 0.000

39 1.591

4 58 2.661

497 2.696

173

174

CHAPTER 5

BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4 BIGRAM POSITION 1ST 2ND 3RD CU

CY DA DD DE DG DI DL DN DO DR DS DU DY EA

EB EC ED EE EF EG

148 2.170 0 0.000 1004 3.002 0 0.000 717 2.856 0 0.000 268 2.428 0 0.000 0 0.000 2146 3.332 238 2.377 0 0.005 234 2.369 7 .845 1296 3.113 0 0.000 10 1.000 90 1.954 0 0.050 0 0.000 35 1.544

0 0.000 0 0.000 44 1.643 24 1.380 204 2.310 78 1.892 0 0.000 19 1.279 3 .477 21 1.322 0 0.000 0 0.000 0 0.050 0 0.000 3589 3.555 13 1.114 119 2.076 16 1.204 5115 3.709 487 2.688 67 1.826

0 0.000 49 1.690 0 0.000 0 0.000 1851 3.267 3 .477 0 0.000 0 0.000 0 0.000 3 .477 0 0.000 204 2.310 0 0.000 401 2.603 529 2.723 0 0.000 0 0.000 1414 3.150 371 2.569 41 1.613 0 0.000

SUM 148 2.170 49 1.690 1048 3.020 24 1.380 2772 3.443 81 1.908 268 2.428 19 1.279 3 .477 2170 3.336 238 2.377 204 2.310 234 2.369 408 2.611 5414 3.734 13 1.114 129 2.111 1520 3.182 5486 3.739 528 2.723 102 2.009

A P P E N D I X 5.2 BIGRAM F R E Q U E N C I E S F O R W O R D S OF L E T T E R L E N G T H 4 BIGRAM P O S I T I O N 1ST 2ND 3RD

SUM

EI

0 0.000

46 1.663

0 0.000

46 1.663

EK

0 0.000

EL

176 2.246

EM

10 1.000

0 0.000 2512 3.400 0 0.000

344 2.537 276 2.441 2149 3.332

344 2.537 2964 3.472 2159 3.334

EN

73 1.863

1158 3.064

8037 3.905

EO

0 0.000

19 1.279

0 0.000

9268 3.967 19 1.279

EP

18 1.255

238 2.377

534 2.728

790 2.898

ER

3 .477

5130 3.710

1646 3.216

6779 3.831

ES

0 0.000

1450 3.161

1394 3.144

2844 3.454

ET

0 0.000

186 2.270

567 2.754

7 53 2.877

EU

0 0.000 1588 3.201

0 0.000 10 1.000

5 .699 0 0.000

5 .699 1598 3.204

EW

0 0.000

159 2.201

803 2.905

962 2.983

EX

7 .845

454 2.657

34 1.531

495 2.695

EY

408 2.611

34 1.531

3645 3.562

4087 3.611

FA

1390 3.143 1233 3.091

0 0.000 0 0.000

6 .778 1021 3.009

1396 3.145 2254 3.353

0 0.000 1480 3.170

0 0.000 0 0.000

5 .699 0 0.000

5 .699 1480 3.170

FL

242 2.384

0 0.000

0 8.000

242 2.384

FO

1204 3.081

0 0.000

0 0.000

1204 3.081

EV

FE FF FI

175

CHAPTER 5

176

BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4 BIGRAM POSITION 2ND 3RD 1ST FR

SUM

4662 3.669 0 0.000

0 0.000 0 0.000

0 0.000 601 2.779

4662 3.669 601 2.779

FU

345 2.538

0 0.000

0 0.000

345 2.538

FY

0 0.000

0 0.000

7 .845

7 .845

GA

583 2.766

0 0.000

13 1.114

596 2.775

GE

103 2.013

69 1.839

304 2.483

476 2.678

GG

0 0.000

35 1.544

0 0.000

35 1.544

GH

0 0.000

0 0.000

517 2.713

517 2.713

GI

647 2 811

0 0.000

0 0.000

647 2.811

GL

61 1 785

21 1.322

0 PI. 0 0 0

82 1.914

GN

0 0 000

0 0.000

94 1.973

94 1.973

GO

296 3 113

3 .477

0 0.000

1299 3.114

GR

292 2.465

0 0.000

0 0.000

292 2.465

GS

0 D.OOO

0 0.000

241 2.382

241 2.382

GU

109 2.037 5393 3.732 2247 3.352

0 0.000 14317 4.156

0 0.000 0 0.000

9 1 52 3.962

4 .602

109 2.037 19710 4.295 11403 4.057

HI

658 2.818

5500 3.740

0 0.000

6158 3.789

HN

0 0.000 1276 3.106 0 0.000

0 0.000

362 2.559

362 2.559

648 2.812 10 1.000

10 1.000

1934 3.286 10 1.000

FT

HA HE

HO

HR

0 0.000

APPENDIX 5 . 2 BI G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 4 BIGRAM POSITION

HU HY IA

IB IC

ID

IE IF IG

IK IL IM IN

I0

IP IR

IS IT

IV IZ JA

1ST

2ND

3RD

SUM

201 2.303 9 .954 0 0.000 0 0.000 0 0.000 221 2.344 0 0.000

361 2.558 0 0.000 21 1.322

562 2.750 9 .954 65 1.813 11 1.041 475 2.677 3172 3.501 433 2.636

0 0.000 3 .477 0 0.000 9 -954 0 0.000 1831 3.263 13 1.114 0 0.000 46 1.663 5 .699 59 1.771 4 .602 0 0.000 261 2.417

999 3.000 631 2.800 1426 3.154 3093 3.490 1649 3.217 2217 3.346 30 1.477 134 2.127 687 2.837 839 2.924 7847 3.895 877 2.943 138 2.140 0 0.000

0 0.008 0 0.000 44 1.643 0 0.000 28 1.447 2205 3.359 0 0.000 0 0.000 0 0.000 0 0.000 4 27 2.630 73 1.863 698 2.844 47 1.672 2 54 2.405 292 2.465 5199 3.716 309 2.490 0 0.000 5 .699 0 0.000

11 1.041 447 2.650 666 2.823 433 2.636

999 3.000 634 2.802 1426 3.154 3529 3.548 1722 3.236 4746 3.676 90 1.954 388 2.589 1025 3.011 6043 3.781 8215 3.915 881 2.945 143 2.155 261 2.417

177

CHAPTER 5

178

BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4 BIGRAM POSITION JE

JI JO JU KA

KE KI

KL KN

KO

KS LA LB LD LE

LF LG

LI LK LL LM

1ST

2ND

3RD

SUM

97 1.987 7 .845 539 2.732 1147 3.060 48 1.681 528 2.723 529 2.723 0 0.000 1136 3.055 11 1.041 0 0.000 1654 3.219 0 0.000 0 0.000 1228 3.089 0 0.000 0 0.000 2835 3.453

0 0.000 0 0.000 0 0.000 0 0.000 20 1.301 0 0.000 62 1.792 3 .477 0 0.000 0 0.000 0 0.000 663 2.822 0 0.000 3 .477 118 2.072 0 0.000 6 .778 79 1.898

0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 3048 3.484 0 0.000 0 0.000 0 0.000 0 0.000 18 1.255 10 1.000 7 .845 1264 3.102 866 2.938 388 2.589 0 0.000 0 0.000

97 1.987 7 .845 539 2.732 1147 3.060

0 0.000 0 0.000 0 0.000

0 0.000 18 1.255 0 0.000

365 2.562 5379 3.731 157 2.196

365 2.562 5397 3.732 157 2.196

68 1.833 3576 3.553 591 2.772 3 .477 1136 3.055 11 1.041 18 1.255 2327 3.367 7 .845 1267 3.103 2212 3.345 388 2.589 6 .778 2914 3.464

APPENDIX 5.2 BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4 BIGRAM POSITION 2N D 3RD 1ST

LO LP LS LT LU LV LY MA MB ME MI MM MN MO MP MS MU MY NA NC ND

2032 3.308 0 0.000 0 0.000 0 0.000 144 2.158 0 0.000 5 .699 3631 3.560 0 0.000 504 2.702 895 2.952 0 0.000 0 0.000 3751 3.574 0 0.000 0 0.000 1961 3.292 35 1.544 350 2.544 0 0.000 0 0.000

2 54 2.405 0 0.000 1245 3.095 4 .602 449 2.652 4 .602 0 0.000 0 0.000 0 0.000 19 1.279 14 1.146 10 1.000 0 0.000 0 0.000 0 0.000 0 0.000 7 .845 0 0.000 12 1.079 539 2.732 102 2.009

11 1.041 316 2.500 24 1.380 508 2.706 0 0.000 0 0.000 1930 3.286 54 1.732 82 1.914 6252 3.796 0 0.000 0 0.000 43 1.633 0 0.000 178 2.250 161 2.207 0 0.000 132 2.121 10 1.000 10 1.000 2140 3.330

SUM 2297 3.361 316 2.500 1269 3.103 512 2.709 593 2.773 4 .602 1935 3.287 3685 3.566 82 1.914 6775 3.831 909 2.959 10 1.000 43 1.633 3751 3.574 178 2.250 161 2.207 1968 3.294 167 2.223 372 2.571 549 2.740 2242 3.351

179

CHAPTER 5

180

BIGRAM FREQUENCIES F O R W O R D S OF LETTER L E N G T H 4 BIGRAM POSITION 2ND 1ST 3RD NE

1196 3.078

552 2.742

NG

0 0.000

NI

SUM

3449 3.538

0 0.000

1701 3.231 1245 3.095

181 2.258

113 2.053

0 0.000

294 2.468

NK

0 0.000

0 0.000

308 2.489

3 08 2.489

NL

0 0.000 0 0.000 330 2.519

1747 3.242

0 0.000

49 1.690 755 2.878

25 1.398 7 .845

1747 3.242 74 1.869

NS

0 0.000

0 0.000

304 2.483

304 2.483

NT

0 0.000

1877 3.273

1349 3.130

3226 3.509

NU

62 1.792

5 .699

67 1.826

NV

0 0.000

0 0.000 7 .845

0 0.000

.845

NY

0 0.000

0 0.808

1161 3.065

1161 3.065

OA

13 1.114

608 2.784

0 0.000

621 2.793

OB

8 .903

81 1.908

4 ,602

93 1.968

oc

0 0.000

123 2.090

133 2.124

OD

28 1.447

395 2.597

10 1.000 1053 3.022

OE

0 0.000

746 2.873

14 1.146

1476 3.169 760 2.881

OF

0 0.000

67 1.826

63 1.799

130 2.114

OG

0 0.000 38 1.580

78 1.892 362 2.559

0 0.000 0 0.000

78 1.892 400 2.602

25 1.398

189 2.276

0 0.000

214 2.330

NN NO

OH 01

1245 3.095

1092 3.038

7

A P P E N D I X 5.2 BIGRAM F R E Q U E N C I E S F O R WORDS O F L E T T E R LENGTH 4 BIGRAM P O S I T I O N 1ST 2ND 3RD OK

23 1.362

OL

SUM

6 .778

39 1.591 1363 3.134

1070 3.029 267 2.427

OM

0 0.000

2934 3.467

4952 3.695

ON

2422 3.384

1854 3.268

867 2.938

00

0 0.000 322 2.508

3703 3.569

0 0.000

330 2.519

302 2.480

5143 3.711 3703 3.569 9 54 2.980

OR

27 1.431

4755 3,677

451 2.654

5233 3.719

0s

0 0.000

2065 3.315

64 1.806

2129 3.328

OT

3 .477

993 2.997

373 2.572

1369 3.136

ou

27 1.431

1582 3.199

14 1.146

1623 3.210

OV

1251 3.097

410 2.613

0 0.000

1661 3.220

ow

58 1.763

1209 3.082

1286 3.109

2553 3.407

10 1.000

0 0.000

5 .699

15 1.176

0 0.000 1638 3.214

170 2.230 28 1.447

3 .477

173 2.238

40 1.602

1706 3.232

PE

104 2.017

332 2.521

558 2.747

994 2.997

PH

65 1.813

0 0.000

0 0.000

65 1.813

PI

269 2.430

34 1.531

0 0.000

303 2.481

PL

560 2.748 666 2.823 30 1.477

0 0.000 552 2.742

0 0.000 0 0.000 0 0.000

560 2.748 1218 3.086 30 1.477

OP

ox OY PA

PO

PR

0 0.000

1132 3.054 1636 3.214 7886 3.897

181

182

CHAPTER 5

BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4 BIGRAM POSITION 1ST 2ND 3RD

PS PT PU

PY QU RA

RB RC

RD RE RF RG RI RK RL RM

RN

RO

RP RR

RS

0 0.000 0 0.000 186 2.270 0 0.000 15 1.176 561 2.749 0 0.000 0 0.000 0 0.000 706 2.849 0 0.000 0 0.000 424 2.627 0 0.000 0 0.000 0 0.000 0 0.000 1162 3.065 0 0.000 0 0.000 0 0.000

0 0.000 0 0.000 32 1.505 0 0.000 0 0.000 273 2.436 0 0.000 13 1.114 0 0.000 860 2.934 0 0.000 21 1.322 176 2.246 0 0.000 0 0.000 253 2.403 0 0.000 4586 3.661 0 0.000 0 0.000 0 0.000

164 2.215 240 2.380 0 0.000 38 1.580 0 0.000 19 1.279 27 1.431 0 0.000 747 2.873 7375 3.868 3 .477 0 0.000 6 .778 1475 3.169 283 2.452 792 2.899 555 2.744 76 1.881 13 1.114 22 1.342 280 2.459

SUM 164 2.215 240 2.380 218 2.338 38 1.580 15 1.176 853 2.931 27 1.431 13 1.114 747 2.873 8941 3.951 3 .477 21 1.322 606 2.782 1475 3.169 283 2.452 1045 3.019 555 2.744 5824 3.765 13 1.114 22 1.342 288 2.459

A P P E N D I X 5.2 BIGRAM F R E Q U E N C I E S F O R W O R D S OF LETTER L E N G T H 4 BIGRAM P O S I T I O N 1ST 2ND 3RD

SUM

RT

0 0.000

66 1.820

845 2.927

9 11 2.960

RU

222 2.346

266 2.425

14 1.146

502 2.701

RX

0 0.000

0 0.000

8 .903

8 .903

RY

0 0.000

0 0.000

1050 3.021

1050 3.021

SA

3211 3.507

0 0.000

0 0.000

3211 3.507

15 1.176

0 0.000

6 .778

21 1.322

SE

1160 3.064

675 2.829

1057 3.024

2892 3.461

SH

628 2.798

0 0.000

342 2.534

970 2.987

SI

837 2.923

44 1.643

0 0.900

881 2.945

SK

52 1.716

18 1.255

2 32 2.365

302 2.480

SL

166 2.220

5 .699

0 0.000

171 2.233

SM

7 .845

0 0.000

0 0.000

7 .845

SN

71 1.851

0 0.000

0 0.000

71 1.851

SO

2387 3.378

SP

139 2.143

0 0.000 0 0.000

1080 3.033 3 .477

3467 3.540 142 2.152

0 0.000

0 0.000

1092 3.038

1092 3.038

ST

448 2.651

0 0.000

6087 3.784

6535 3.815

SU

1665 3.221

0 0.000

0 0.000

1665 3.221

29 1.462 0 0.000 1022 3.009

0 0.000 0 0.000 159 2.201

0 0.000 192 2.283

29 1.462 192 2.283 1354 3.132

sc

ss

sw SY TA

173 2.238

183

184

CHAPTER 5

B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 4

B I G R A M POSITION 1ST 2ND 3RD

TC TE TH TI TO TR TS TT TU TW TY UA

UB

uc UD UE

OF UG UI

UK UL

0 0.000 693 2.841 24777 4.394 1818 3.260 1384 3.141 453 2.656 0 0.000 0 0.000 282 2.450 7 .845 200 2.301 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 21 1.322 0 0.000 0 0.000 0 0.000

5 .699 219 2.340 0 0.000 10 1.000 163 2.212 0 0.000 0 0.000 4 .602 3 ,417 0 0.000 0 0.000 28 1.447 78 1.892 2366 3.374 46 1.663 26 1.415 5 .699 75 1.875 86 1.934 14 1.146 561 2.749

0 0.000 990 2.996 8165 3.912 0 0.000 1903 3.279 0 0.000 536 2.729 12 1.079 0 0.000 0 0.000 472 2.674 0 0.000 148 2.170 0 0.000 23 1.362 389 2.590 0 0.000 64 1.806 0 0.000 3 .477 94 1.973

SUM 5 .699 1902 3.279 32942 4.518 1828 3.262 3450 3.538 4 53 2.656 536 2.729 16 1.204 285 2.455 7 .845 672 2.827 28 1.447 226 2.354 2366 3.374 69 1.839 415 2.618 5 .699 160 2.204 86 1.934 17 1.230 655 2.816

A P P E N D I X 5.2 BIGRAM F R E Q U E N C I E S F O R W O R D S OF LETTER L E N G T H 4 BIGRAM P O S I T I O N 1ST 2ND 3RD UM

0 0.000

UN

SUM

19 1.279

108 2.033

122 2.086

89 1.949 447 2.650

16 1.204

585 2.767

UP

495 2.695

14 1.146

20 1.301

529 2.723

UR

21 1.322

801 2.904

1497 3.175

2319 3.365

US

675 2.829

2147 3.332

387 2.588

3209 3.506

UT

6 .778

212 2.326

61 1.785

279 2.446

0 0.000

0 0.000

30 1.477

30 1.477

0 0.000

31 1.491

0 0.000

31 1.491

0 0.000 109 2.037 0 0.000

16 1.204 12 1.079

0 0.000 4 .602

16 1.204 125 2.097

0 0.000

4 .602

4 .602

VE

857 2.933

2759 3.441

5661 3.753

9277 3.967

VI

252 2.401

72 1.857

0 0.000

324 2.511

90 1.954

0 0.000

0 0.000

90 1.954

0 0.000 1117 3.048

0 0.000 470 2.672

54 1.732 4 .602

54 1.732 1591 3.202

WD

0 9.000

0 0.000

3 .477

3 .477

WE

5289 3.723

50 1.699

12 1.079

5351 3.728

WH

4407 3.644 10328 4.014 0 0.000

0 0.000 22 1.342 0 0.000

0 0.000 0 0.000 14 1.146

4407 3.644 10350 4.015 14 1.146

ux UY

uz VA VD

vo VY WA

WI WK

185

CHAPTER 5

186

BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 4

BIGRAM P O S I T I O N 1ST 2ND 3RD

WL WN WO

WR

ws XE

XI XT YA

YD

YE YM YN YO

YP YR

YS YT

YU ZE 21

0 0 000 0 0 000 214 3 084 12 1.079 0 0.000 0 0.000 0 0.000 0 0.000 69 1.839 0 0.000 694 2.841 0 0.000 0 0.000 1227 3.089 0 0.000 0 0.000 0 0.000 0 0.000 6

.I78

37 1.568 16 1.204

0 0.000 13 1.114 0 0.000 0 0.000 0 0.000 17 1.230 45 1.653 0 0.000 0 0.000 0 0.000 415 2.618 9 .954 5 .699 0 0.000 200 2.301 9 ,954 0 0.000 35 1.544 0 0.000 0 0.000 0 0.000

27 1.431 1169 3.068 0 0.000 0 0.000 297 2.473 0 0.000 16 1.204 4 54 2.657 0 0.000 5 .699 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 989 2.995 4 .602 0 0.000 163 2.212 13 1.114

SUM 27 1.431 1182 3.073 1214 3.084 12 1.079 297 2.473 17 1.230 61 1.785 454 2.657 69 1.839 5 .699 1109 3.045 9 .954 5 .699 1227 3.089 200 2.301 9 ,954 989 2.995 39 1.591 6 ,778 200 2.301 29 1.462

A P P E N D I X 5.2 BIGRAM F R E Q U E N C I E S F O R W O R D S OF LETTER LENGTH 4 BIGRAM P O S I T I O N 1ST 2ND 3RD ZO

ZY

zz

11 1.041 0 0.000 0 0.000

0 0.000 0 0.000 0 0.000

0 0.000 14 1.146 115 2.061

SUM 11 1.041 14 1.146 115 2.061

187

188

CHAPTER 5

BIGRAM F R E Q U E N C I E S FOR WORDS OF L E T T E R LENGTH 5 BIGRAM P O S I T I O N 1ST 2ND 3 RD

4TH

SUM

0 0.000

17 1.230

0 0.000

2592 3.414

AA

7 .845

0 0.000

AB

2151 3.333

438 2.641

10 1.000 3 .477

AC

109 2.037

309 2.490

1625 3.211

14 1.146

2057 3.313

AD

308 2.489

2 37 2.375

541 2.733

285 2.455

1371 3.137

AF

1070 3.029 686 2.836

5 .699 241 2.382

171 2.233

3 .477

1249 3.097

315 2.498

0 0.000

1242 3.094

AH

109 2.037

4 .602

0 0.000

26 1.415

139 2.143

A1

45 1.653

581 2.764

1088 3.037

7 .845

1721 3.236

AJ

0 0.000

0 0.000

0 0.000

247 2.393

AK

0 0.000

247 2.393 644 2.809

120 2.079

225 2.352

989 2.995

AL

875 2.942

810 2.908

1066 3.028

1616 3.208

4367 3.640

AM

396 2.598

362 2.559

305 2.484

111 2.045

1174 3.070

AN

176 2.246

994 2.997

1312 3.118

1228 3.089

3710 3.569

A0

0 0.000

0 0.000

17 1.230

0 0.000

17 1.230

AP

204 2.310

384 2.584

122 2.086

32 1.505

742 2.870

AR

410 2.613

1934 3.286

2670 3.427

394 2.595

5408 3.733

AS

489 2.689

884 2.946

1041 3.017

468 2.670

2882 3.460

AT

69 1.839

1449 3.161

1260 3.100

736 2.867

3514 3.546

AU

8 .903

274 2.438

8 .903

0 0.000

290 2.462

AV

62 1.792 185 2.267

332 2.521

416 2.619 98 1.991

0 0.000

810 2.908

15 1.176

310 2.491

AG

AW

12 1.079

APPENDIX 5.2

189

BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 5 BIGRAM POSITION 1ST 2ND 3RD

AX AY A2

BA BB

BE BI BL BO

BR BS BT

BU BY CA

cc CE CH CI CK CL

0 0.000 0 0.000 0 0.000 745 2.872 0 0.000 1556 3.192 269 2.430 654 2.816 668 2.825 984 2.993 0 0.000 0 0.000 372 2.571 16 1.204 731 2.864 0 0.000 121 2.083 925 2.966 161 2.207 0 0.000 1097 3.040

65 1.813 211 2.324 38 1.580 0 0.000 7 .845 0 0.000 7

.845 0 0.000 2115 3.325 0 0.000 0 0.000 b7

0.000 18 1.255 4 .602 86 1.934 43 1.633 146 2.164 3 .477 7 .845 0 0.000 0 0.000

0 0.000 74 1.869 44 1.643 61 1.785 60 1.778 144 2.158 77 1.886 287 2.458 162 2.210 3 .477 0 0.000 12 1.079 20 1.301 0 0.000 337 2.528 0 0.000 187 2.272 3 .477 12 1.079 112 2.049 81 1.908

4TH

SUM

19 1.279 384 2.584 0 0.000 0 0.000 0 0.000 161 2.207 21 1.322 0 0.d00 4 .602 0 0.000 80 1.903 114 2.057 0 0.000 58 1.763 0 0.c100 0 0.000 2712 3.433 4479 3.651 0 0.000 1000 3.000 0 0.000

84 1.924 669 2.825 82 1.914 806 2.906 67 1.826 1861 3.270 374 2.573 941 2.974 2949 3.470 987 2.994 80 1.903 126 2.100 410 2.613 78 1.892 1154 3.062 43 1.633 3166 3.501 5410 3.733 180 2.255 1112 3.046 1178 3.071

190

CHAPTER 5

BIGRAM F R E Q U E N C I E S F O R WORDS OF L E T T E R L E N G T H 5 BIGRAM P O S I T I O N 1ST 2ND 3RD

4TH

SUM

2783 3.445 457 2.660

134 2.127 82 1.914

18 1.255 0 0.000

0 0.000 0 0.000

2935 3.468

cs

0 0.000

0 0.000

0 0.000

7 .845

7 .845

CT

0 0.000

42 1.623

100 2.000

87 1.940

2 29 2.360

CU

113 2.053

13 1.114

88 1.944

0 0.000

214 2.330

CY

28 1.447

0 0.000

0 0.000

47 1.672

75 1.875

DA

412 2.615

50 1.699

321 2.507

5 .699

788 2.897

DD

0 0.000

211 2.324

34 1.531

0 0.000

245 2.389

DE

522 2.718

208 2.318

1814 3.259

5 58 2.747

3102 3.492

DG

0 0.000

44 1.643

143 2.155

0 0.000

187 2.272

DI

112 2.049

11 1.041

225 2.352

0 0.000

348 2.542

DL

0 0.000

7 .845

59 1.771

0 0.000

66 1.820

DM

0 0.000

37 1.568

0 0.000

0 0.000

37 1.568

DO

450 2.653 775 2.889

21 1.322

30 1.477

0 0.000

9 .954

11 1.041 0 0.000

512 2.709 7 84 2.894

DS

0 0.000

0 0.000

19 1.279

1736 3.240

1755 3.244

DT

0 0.000

0 0.000

14 1.146

0 0.000

14 1.146

DU

52 1.716

25 1.398

13 1.114

3 .477

DW

11 1.041 45 1.653

11 1.041 0 0.000 3865 3.587

0

0 0.000

0 0.000 547 2.738

93 1.968 22 1.342 592 2.772

2082 3.318

12 1.079

6532 3.815

CO CR

OR

DY EA

573 2.758

FI. 0 0 0

539 2.732

191

APPENDIX 5 . 2 B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 5

EB EC

ED EE

EF EG

EH EI

EK EL EM

EN EO

EP EQ ER

ES ET EU EV

EW

B I G R A M POSITION 3RD 1ST 2ND

4TH

SUM

0 0.000 0 0.000 89 1.949 0 0.000 0 0.000 14 1.146 0 0.000 104 2.017 0 0.000 77 1.886 64 1.806 303 2.481

44 1.643 18 1.255 41 1.613 883 2.946 27 1.431 628 2.798 5 .699 763 2.883 0 0.000 474 2.676 31 1.491 685 2.836

4 .602 261 2.417 237 2.375 930 2.968 10 1.000 18 1.255 0 0.000 2688 3.429 151 2.179 490 2.690 589 2.770 486 2.687

0 0.000 0 0.000 2825 3.451 665 2.823 210 2.322 0 0.000 0 0.000 0 0.000 95 978 752 876 19 279 686 227

48 1.681 279 2.446 3192 3.504 2478 3.394 247 2.393 660 2.820 5 .699 3555 3.551 246 2.391 1793 3.254 703 2.847 3160 3.500

0 0.000 6 .778 90 1.954 79 1.898 31 1.491

0 0.000 123 2.090 0 0.000 494 2.694 166 2.220 128 2.107 0 0.000 1088 3.031 151 2.179

0 0.000 216 2.334 0 0.000 4347 3.638 2095 3.321 178 2.250 9 .954 3 .477 51 1.708

3 .477 126 2.100 0 0.000 7346 3.866 3937 3.595 297 2.473 0 0.000 0 0.000 71 1.851

3 .477 471 2.673 90 1.954 12266 4.089 6229 3.794 614 2.788 9 . 9 54 1688 3.227 273 2.436

11 1.041 0 0.000 597 2.776 0 0.000

192

CHAPTER 5


BIGRAM POSITION 1ST 2N D 3RD

151 2.179 0 0.000 628 2.798 245 2.389 0 0.000 2400 3.380 395 2.597 1171 3.069 541 2.733 0 0.000 0 0.000 234 2.369

89 1.949 6 .778 0 0.000 0 0.000 80 1.903 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 1438 3.158 0 0.000

GA

160 2.204

578 2.762

GE

3 .477 0 0.000 15 1.176 665 2.823 201 2.303 0 0.000 0 0.000 521 2.717

44 1.643 0 0.000 0 0.000

EX EY

FA FE FF FI FL FO FR FS FT FU

GG GH

GI GL GM

GN GO

4 .602 0 0.000 0 0.000 0 0.000 9 .954

0 0.000 0 0.000 0 0.000 112 2.049 0 0.000 0 0.000 63 1.799 0 0.000 El

0.000 0 0.000 122 2.086 17 1.230 4 56 2.659 290 2.462 18 1.255 2413 3.383 162 2.210 56 1.748 4 .602 68 1.833 69 1.839

4TH

SUM

93 1.968 342 2.534 0 0.000 84 1.924 189 2.276 0 0.000 0 0.000 0 0.000 0 0.000 12 1.079 162 2.210 0 0.000 0 0.000 1040 3.017 3 .477 138 2.140 0 0.000 0 0.000 0 0.000 7 .845 72 1.857

333 2.522 348 2.542 628 2.798 441 2.644 269 2.430 2400 3.380 458 2.661 1171 3.069 541 2.733 12 1.079 1722 3.236 251 2.400 1194 3.077 1377 3.139 21 1.322 2566 3.409 831 2.920 2 57 2.410 4 .602 75 1.875 671 2.827

APPENDIX 5 . 2

193

B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 5 B I G R A M POSITION GR

GS GU

GY HA

HE HI HN

HO HR

HS HT HU HY IA

IB

IC ID IE

IF IG

1ST

2ND

3RD

4TH

SUM

1763 3.246 0 0.000 233 2.367

51 1.708 0 0.000 0 0.000

0 0.000 192 2.283 0 0.000

4 .602 611 2.786 823 2.915 105 2.021 0 0.000 1404 3.147 0 0.000 0 0.000 0 0.000

14 1.146 924 2.966 8507 3.930 6209 3.793 0 0.000 2421 3.384 713 2.853 0 0.000 0 0.000

149 2.173 0 0.000 111 2.045 0 0.000 0 0.000 1717 3.235 4 .602 6 .778 8 .903 5 .699 0 0.000 0 0.000

1963 3.293 192 2.283 344 2.537 41 1.613 1535 3.186 11058 4.044 6323 3.801 6 .778 3837 3.584 718 2.856 28 1.447 2413 3.383

399 2.601 6 .778 0 0.000 0 0.000 0 0.000 211 2.324

27 1.431 7 ,845 87 1.940 93 1.968 19 1.279 2 57 2.410 534 2.728 180 2.255 2468 3.392

0 0.000 0 0.000 0 0.000

0 0.000 0 0.000 144 2.158 12 1.079 4245 3.628 229 2.360 594 2.774 199 2.299 26 1.415

23 1.362 0 0.000 11 1.041 5 .699 0 0.000 4 .602 0 0.000 28 1.447 2413 3.383 0 0.000 4 .602 123 2.090 0 0.000 555 2.752 333 2.522 112 2.049 27 1.431 0 0.000

426 2.629 17 1.230 3 54 2.549 105 2.021 4829 3.684 1030 3.013 1240 3.093 4 06 2.609 2494 3.397

CHAPTER 5

194

BIGRAM FREQUENCIES F O R WORDS OF LETTER L E N G T H 5

I1 IK IL IM IN I0 IP IR IS IT IV IX I2

JA JE JI JO

JU KA KE KI

BIGRAM POSITION 3RD 2N D 1ST

4TH

SUM

0 0.000 20 1.301 2279 3.358 91 1.959 3331 3.523 255 2.407 92 1.964 325 2.512 305 2.484 1217 3.085 174 2.241 0 0.000 34 1.531 0 0.000 0 0.000 0 0.000 291 2.464 0 0.000 0 0.000 1151 3.061 5 .699

4

.602 0 0.000 722 2.859 98 1.991 1090 3.037 156 2.193 34 1.531 2752 3.440 447 2.650 339 2.530 0 0.000 30 1.477 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 358 2.554 0 0.000

4 .602 102 2.009 3536 3.549 758 2.880 6050 3.782 443 2.646 152 2.182 5038 3.702 1147 3.060 1926 3.285 1244 3.095 226 2.354 58 1.763 142 2.152 86 1.934 11 1.041 446 2.649 131 2.117 27 1.431 1530 3.185 155 2.190

0 0.000 0 0.000 0 0.000 131 2.117 228 2.358 8 .903 0 0.000 47 1.672 169 2.228 106 2.025 17 1.230 0 0.000 0 0.000 142 2.152 86 1.934 11 1.041 155 2.190 131 2.117 27 1.431 21

1.322 68 1.833

0 0.000 82 1.914 535 2.728 438 2.641 1401 3.146 24 1.380 26 1.415 1914 3.282 2 26 2.354 264 2.422 1053 3.022 196 2.292 24 1.380 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 82 1.914

APPENDIX 5 . 2

195


KL KN KO

KS KU KY LA LB

B I G R A M POSITION 3RD 1ST 2N D

4TH

SUM

8 .903 0 0.000 0 0.000 0 0.000 0 0.000 18 1.255 113 2.053 3 .477

0 0.000 0 0.000 0 0.000 812 2.910 0 0.000 72 1.857 28 1.447 0 0.000

8 .903 490 2.690 12 1.079 812 2.910 3 .477 90 1.954 3235 3.510 19 1.279

0 0.000 49 1.690 731 2.864 8 .903 5 .699 5 .699 232 2.365 65 1.813 789 2.897 39 1.591 405 2.607 53 1.724 38 1.580

0 0.000 5715 3.757 1837 3.264 12 1.079 0 0.000 0 0.000 0 0.000 3 .477 1806 3.257 19 1.279 10 1.000 4 .602 1006 3.003

5 .699 5872 3.769 4205 3.624 20 1.301 5 .699 5 .699 1478 3.170 68 1.833 2726 3.436 64 1.806 2754 3.440 57 1.756 1048 3.020

0 0.000 490 2.690 12 1.079 0 0.000 0 0.000 0 0.000 1119 3.049 0 0.000

LC

0 0.000

LD

0 0.000 1063 3.027 0 0.000

LE

LF LG

LH LI

LK LL LM

LO

LP LS

0 0.000 0 0.000 958 2.981 0 0.0063 10 1.000 0 0.000 878 2.943 0 0 * 000 0 0.000

0 0.000 0 0.000 0 0.000 0 0.000 3 .477 0 0.000 1975 3.296 16 1.204 5 .699 108 2.033 574 2.759 0 0.000 0 0.000 0 0.6300 288 2.459 0 0.000 121 2.083 6 -778 1461 3.165 0 0.000 4 .602

CHAPTER 5

196

BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 5 BIGRAM POSITION

LT LU LV

LY MA MB ME

MI ML MM MN

MO

MP YS

MU

MY NA NC

ND NE NG

1ST

2ND

3RD

4TH

SUM

0 0.000 111 2.045 0 0.000 48 1.681 978 2.990 0 0.000 650 2.813 1109 3.045

24 1.380 191 2.281 6 .778 4 .602 693 2.841 0 0.000 34 1.531 115 2.061

40 1.602 200 2.301 26 1.415 0 0.000 581 2.764 44 1.643 1162 3.065 105 2.021

213 2.328 0 0.000 0 0.000 1055 3.023 67 1.826 27 1.431 283 2.452 22 1.342

271 2.442 502 2.701 32 1.505 1107 3.044 2319 3.365 71 1.851 2129 3.328 1351 3.131

0 0.000 0 0.000 0 0.000 1236 3.092 0 0.000

0 0.000 0 0.000 0 0.000 416 2.619 96 1.982

12 1.079 46 1.663 6 .778 107 2.029

0 0.000 241 2.382 6 .778 281 2.449 0 0.000 0 0.000 1025 3.011 0 0.000

0 0.000 3 .477 0 0.000 61 1.785 62 1.792 922 2.965 144 2.158 162 2.210

0 0.000 0 0.000 0 0.000 0 0.000 27 1.431 1098 3.041 0 0.000 117 2.068 101 2.004 0 0.000 1331 3.124 607 2.783 3346 3.525

12 1.079 46 1.663 6 .778 1759 3.245 159 2.201 1098 3.041 248 2.394 123 2.090 621 2.793 1028 3.012 3004 3.478 2637 3.421 3878 3.589

36 1.556 0 0.000 4 .602 0 0.000 178 2.250 966 2.985 751 2.876 861 2.935 370 2.568

APPENDIX 5.2

197

BIGRAM FREQUENCIES F O R WORDS OF L E T T E R LENGTH 5 BIGRAM POSITION 1ST

2ND

3RD

4TH

SUM

467 2.669 0 0.000

441 2.644 44 1.643

53 1.724 0 0.000

0 0.000 0 0.000

961 2.983 44 1.643

NK

0 0.000

8 .903

113 2.053

711 2.852

832 2.920

NL

0 0.000

4 .602

0 0.000

0 0.000

4 .602

NN

0 0.000 546 2.737 0 0.000

58 1.763

113 2.053

6 .7ia

177 2.248

370 2.568

38 1.580

20 1.301

152 2.182 0 0.000

1106 3.044 20 1.301

0 0.000

0 0.000

99 1.996

0.000

99 1.996

NS

0 0.000

38 1.580

34fJ 2.531

819 2.913

1197 3.078

NT

0 0.000

565 2.752

313 2.496

1403 3.147

2281 3.358

NU

17 1.230

0 0.000

22 1.342

0 0.000

39 1.591

NX

0 0.000

0 0.000

0 0.000

9 .954

9 .9 54

NY

0 0.000

0 0.000

0 0.000

142 2.152

142 2.152

OA

3 .477

573 2.758

105 2 . fJ21

0 0.000

681 2.833

0 0.000 77 1.886

108 2.033

23 1.362

0 0.000

400 2.602

295 2.470

3 .477

131 2.117 775 2.889

OD

17 1.230

419 2.622

259 2.413

361 2.558

1056 3.024

OE

0 0.000

114 2.057

44 1.643

11 1.041

169 2.228

OF

448 2.651 0 0.000 0 0.000

5 .599 61 1.785

1.176 0 0.000

45 1.653 0 0.000

513 2.710 61 1.785

9 .954

0 0.000

0 0.000

9 .954

NI NJ

NO NP NR

OB

oc

OG OH

15

0 0.000 0

198

CHAPTER 5


BIGRAM POSITION 3 RD 2ND 1ST 01

OK OL

OM ON

00 OP OR

0s OT OU

ov OW

ox OY 02

PA PE PH PI PL

3 .477 0 0.000 98 1.991 0 0.000 53 1.724 0 0.000 63 1.799 404 2.606 9 .954 1702 3.231 105 2.021 11 1.041 71 1.851 0 0.000 0 0.000 0 0.000 838 2.923 318 2.502 143 2.155 297 2.473 1117 3.048

1306 3.116 50 1.699 489 2.689 775 2.889 820 2.914 663 2.822 109 2.037 2726 3.436 279 2.446 663 2.822 7649 3.884 500 2.699 581 2.764 14 1.146 94 1.973 57 1.756 301 2.479 446 2.649 0 0.000 71 1.851 30 1.477

4TH

SUM

69 1.839 411 2.614 373 2.572 99 1.996 1475 3.169 724 2.860 129 2.111 7 59 2.880 1619 3.209 4 29 2.632 2342 3.370 449 2.652 972 2.988 7 .845 10 1.000 4 .602 52 1.716

0 0.000 63 1.799 8 .903 46 1.663 396 2.598 3 .477 25 1.398 1243 3.094 28 1.447 88 1.944 0 0.000 9 .954 309 2.490 0 0.000 44 1.643 0 0.000 5 .699

1378 3.139 524 2.719 968 2.986 920 2.964 2744 3.438 1390 3.143 326 2.513 5132 3.710 1935 3.287 2882 3.460 10096 4.004 969 2.986 1933 3.286 21 1.322 148 2.170 61 1.785 1196 3.078

501 2.700 0 0.000 72 1.857 146 2.164

134 2.127 39 1.591 0 0.000 0 0.000

1399 3.146 182 2.260 440 2.643 1293 3.112

APPENDIX 5.2

199

B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 5 B I G R A M POSITION

PO

1ST

2ND

3RD

4TH

SUM

1028 3.012 0 0.000 615 2.789 0 0.000 0 0.000 62 1.792 0 0.000 515 2.712

25 1.398 103 2.013 0 0.000 10 1.000 117 2.068 20 1.301 0 0.000 0 0.000 292 2.465 17 1.230 419 2.622 482 2.683 1058 3.024 0 0.000 404 2.606 0 0.000 255 2.407 199 2.299

4 .602 0 0.000 0 0.000 491 2.691 108 2.033 0 0.000 98 1.991 0 0.000 123 2.090 0 0.000 0 0.000 824 2.916 4157 3.619 7 .845 0 0.000 0 0.000 16 1.204 91 1.959

1208 3.082 240 2.380 713 2.853 515 2.712 229 2.360 85 1.929 98 1.991 630 2.799 2418 3.383 75 1.875 419 2.622 1682 3.226 7607 3.881 7 .845 488 2.688 108 2.033 2748 3.439 290 2.462

1319 3.120 408 2.611 90 1.954

12 1.079 71 1.851 116 2.064

1331 3.124 543 2.735 2 29 2.360

RK

0 0.000

151 2.179 137 2.137 98 1.991 14 1.146 4 .602 3 .477 0 0.000 115 2.061 1278 3.107 58 1.763 0 0.000 376 2.575 1906 3.280 0 0.000 84 1.924 0 0.000 1508 3.178 0 0.000

RL

0 0.000 0 0.000 0 0.000

0 0.000 64 1.806 23 1.362

PP PR PS PT PU PY

QU RA RB RC

RD RE

RF RG RH RI

RM RN

725 2.860 0 0.000 0 0.000 0 0.000 486 2.687 0 0.000 0 0.000 108 2.033 969 2.986

200

CHAPTER 5

BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 5 B I G R A M POSITION

1ST

2ND

3RD

4TH

SUM

548 2.739 0 0.000 0 0.000 0 0.000 0 0.000 200 2.301 0 0.000 0 0.000 375 2.574 370 2.568 943 2.975 1655 3.219

1926 3.285 0 0.000 64 1.806 0 0.000 0 0.000 512 2.709 0 0.000 19 1.279 24 1.380 9 .954 6 .778 6 .778

131 2.117 109 2.037 362 2.559 1718 3.235 1028 3.012 61 1.785 171 2.233 0 0.000 55 1.740 7 .845 519 2.715 0 0.000

115 2.061 72 1.857 0 0.000 1416 3.151 997 2.999 5 .699 0 0.000 1254 3.098 6 .778 0 0.000 4720 3.674 289 2.461

2720 3.435 181 2.258 4 26 2.629 3134 3.496 2025 3.306 778 2.891 171 2.233 1273 3.105 460 2.663 386 2.587 6188 3.792

SI

1025 3.011

SK

85 1.929 254 2.405 766 2.884 61 1.785

222 2.346 398 2.600 7 .845 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 191 2.281

700 2.845 51 1.708 6 .778 0 0.000 0 0.000 31 1.491 5 .699 0 0.000 17 1.230

0 0.000 7 .845 0 0.000 3 .477 0 0.000 7 .845 25 1.398 0 0.000 787 2.896

1947 3.289 541 2.733 267 2.427

RO RP RR RS

RT RU

RV RY SA SC SE SH

SL SM SN

SO

750 2.875

SP

896 2.952 25 1.398 0 0.000

SQ SS

1950 3.290

769 2.886 61 1.785 788 2.897 926 2.967 25 1.398 995 2.998

A P P E N D I X 5.2

201

B I G R A M F R E Q U E N C I E S F O R WORDS O F L E T T E R LENGTH 5 BIGRAM P O S I T I O N 1ST 2ND 3RD

4TH

SUM

3855 3.586 156 2.193

0 0.000 96 1.982

499 2.698 216 2.334

2236 3.349 0 0.000

6590 3.819 468 2.670

sw

306 2.486

0 0.000

0 0.000

0 0.000

306 2.486

SY

4 .602

0 0.000

0 0.000

28 1.447

32 1.505

TA

809 2.908 0 0.000 0 0.000

1551 3.191 0 0.000

362 2.559 2 68 2.428

50 1.699 0 0.000

2772 3.443 268 2.428

0 0.000

3 .477

0 0.000

3 -477

TE

624 2.795

372 2.571

3129 3.495

2104 3.323

6229 3.794

TH

9669 3.985

1713 3.234

44 1.643

2068 3.316

13494 4.130

TI

517 2.713

8 56 2.932

591 2.772

0 0.000

1964 3.293

TL

0 0.000

12 1.079

81 1.908

0 0.000

93 1.968

TO

870 2.940

764 2.883

98 1.991

36 1.556

1768 3.247

TR

1212 3.084

60 1.778

85 1.929

0 0.000

1357 3.133

TS

0 0.080

0 0.000

0 0.000

1173 3.069

1173 3.069

TT

0 0.000

29 1.462

58 1.763

29 1.462

116 2.064

TU

109 2.037

301 2.479

8 .903

0 0.000

418 2.621

TW

109 2.037

0 0.000

0 0.000

0 0.0Q0

109 2.037

TY

124 2.093

98 1.991

0 0.00B

591 2.772

813 2.910

TZ

0 0.000 0 0.000 0 0.000

0 0.000 51 1.708 62 1.792

0 0.000 211 2.324 138 2.140

3 .477

3 .477

0 0.000

262 2.418

9 .954

209 2.320

ST

su

TC TD

UA UB

202

CHAPTER 5

BIGRAM F R E Q U E N C I E S F O R WORDS OF L E T T E R LENGTH 5 BIGRAM P O S I T I O N 2N D 1ST 3RD

uc

0 0.000

UD

4TH

SUM

225 2.352

0 0.000

49 1.690 110 2.041

268 2.428

0 0.000 108 2.033

UE

0 0.000

161 2.207

66 1.820

425 2.628

274 2.438 486 2.687 652 2.814

UF

0 0.000 0 0.000

0 0.000

44 1.643

0 0.000

44 1.643

108 2.033

176 2.246

0 0.000

284 2.453

U I

0 0.000

773 2.888

129 2.111

0 0.000

902 2.955

UL

5 .699

301 2.479

4442 3.648

17 1.230

4765 3.678

UM

0 0.000

384 2.584

57 1.756

37 1.568

478 2.679

UN

1588 3.201

283 2.452

1541 3.188

51 1.708

3463 3.539

00

0 0.000

21 1.322

0 0.000

0 0.000

21 1.322

UP

86 1.934

28 1.447

0 0.000

402 2.604

516 2.713

UR

85 1.929

351 2.545

463 2.666

56 1.748

955 2.980

US

261 2.417

304 2.483

902 2.955

150 2.176

1617 3.209

UT

13 1.114

65 1.813

616 2.790

1876 3.273

2570 3.410

ux

0 0.000 0 0.000

0 0.000

8 .903 7 .845

51 1.708

8 .903 0 0.000 0 0.000

327 2.515

UG

VA

'262 2.418

0 0.000 7 .845 14 1.146

VE

70 1.845

583 2.766

2570 3.410

1125 3.051

4348 3.638

VI

294 2.468

9 .954

2 77 2.442

0 0.000

580 2.763

VO

309 2.490

81 1.908

3 .477

0 0.000

81 1.908 0 0.000

0 0.000 114 2.057

2.673 117 2.068

uz

VY

0 0.000

4ii

203

APPENDIX 5 . 2 B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 5 B I G R A M POSITION WA

WD

WE WF WH WI WL

WN

WO WR

ws wu

1ST

2ND

3RD

4TH

SUM

961 2.983 0 0.000 201 2.303 0 0.000 6184 3.791 207 2.316 0 0.000 0 0.000 4632 3.666 446 2.649 0 0.000 0 0.000

165 2.217 0 0.000 172 2.236 17 1.230 0 0.000 178 2.250 0 0.000 67 1.826 35 1.544 0 0.000 0 0.000 48 1.681 0 0.000 27 1.431 11 1.041 63 1.799 0 0.000 50 1.699 0 0.000 3 .477 0 0,000

0 0.000 7 .845 569 2.755 0 0.000 0 0.000 68 1.833 38 1.580 73 1.863 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 74 1.869 211 2.324 3 .477 25 1.398 51 1.708 0 0.000 78 1.892 134 2.127

0 0.000 53 1.724 0 0.000 0 0.000 0 0.000 0 0.000 15 1.176 738 2.868 0 0.000 0 0.000 311 2.493 0 0.000 4 .602

1126 3.052 60 1.778 942 2.974 17 1.230 6184 3.791 453 2.656 53 1.724 878 2.943 4667 3.669 446 2.649 311 2.493 48 1.681 7 .845

0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 7 .845 0 0.000 0 0.000

101 2.004 222 2.346 66 1.820 25 1.398 101 2.004 7 .845 149 2.173 134 2.127

WY

3 .477

XA

0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 68 1.833 0 0.000

XE

XI

xo XT XY YA

YB

204

CHAPTER 5


YC

YD YE YI

YL YM

YN YO

YP YR

YS YT ZA

ZE ZI ZO

ZY ZZ

B I G R A M POSITION 1ST 2N D 3RD

4TH

SUM

21 1.322 0 0.000 35 1.544 5 .699 113 2.053 3 .477 12 1.079 38 1.580 14 1.146 0 0.000 4 .602 0 0.000 0 0.000 84 1.924 12 1.079 15 1.176 0 0.000 15 1.176

0 0.000 10 1.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 18 1.255 0 0.000 0 0.000 74 1.869 0 0.000 3 .477 48 1.681 0 0.008 0 0.000 46 1.663 0 0.000

45 1.653 10 1.000 987 2.994 118 2.012 124 2.093 9 .954 12 1.079 548 2.739 137 2.137 36 1.556 78 1.892 6 .778 3 .417 132 2.121 12 1.079 18 1.255 46 1.663 15 1.176

0 0.000 0 0.000 952 2.979 35 1.544 0 0.000 0 0.000 0 0.000 492 2.692 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 3 .477 0 0.000 0 0.000

24 1.380 0 0.000 0 0.000 18 1.892 11 1.041 6 .778 0 0.000 0 0.000 123 2.090 36 1.556 0 0.000 6 .778 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

205


B I G R A M POSITION 3RD 2N D 1ST AA

AB AC AD

AE

AF AG AH

A1 AJ AK

AL AM AN

AP AQ AR

AS AT AU AV

0 0.000 170 2.230 967 2.985

141 2.149 8 .903 232 2.365 192 2.283 0 0.000 12 1.079 0 0.000 0 0.000 1094 3.039 202 2.305 604 2.781 185 2.267 0 0.000 906 2.957 344 2.537 253 2.403 139 2.143 49 1.690

0 0.000 122 2.086 406 2.609 131 2.117 6 .778 64 1.806 102 2.009 0 0.000 494 2.694 3 .477 470 2.672 1430 3.155

0 0.000 140 2.146 332 2.521 363 2.560 0 0.000 11 1.041 221 2.344 22 1.342 324 2.511 0 0.000 103 2.013 472 2.674

743 2.871 1377 3.139 160 2.204 0 0.000 1830 3.262 715 2.854 1950 3.290 368 2.566 388 2.589

85 1.929 895 2.952 148 2.170 6 .778 865 2.937 4 37 2,640 9 67 2.985 96 1.982 257 2.410

4TH

5TH

SUM

7 .845 0 0.000 277 2.442 167 2.223 15 1.176 0 0.000 156 2.193 0 0.000 462 2.665 0 0.000 46 1.663 270 2.431 316 2.500 491 2.691 71 1.851 0 0.000 933 2.970 151 2.179

0 0.000 0 0.000 4 .602 185 2.267 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 10 1.000 1558 3.193 83 1.919 310 2.491 4 .602 0 0.000 278 2.444 220 2.342

7 .845 432 2.635 1986 3.298

370 2.568 0 0.000 13 1.114

193 2.286 57 1.756 0 fl.000

3733 3.572 660 2.820 707 2.849

987 2.994 29 1.462 3 07 2.487 671 2.827 22 1.342 1292 3.111 3 .477 629 2.799 4824 3.683 1429 3.155 3677 3.565 568 2.754 6 .778 4812 3.682 1867 3.271

2 06

CHAPTER 5

B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 6 B I G R A M POSITION 2N D 3RD 1ST AW

AX AY AZ

BA BB

BE

31 1.491 0 0.000 0 0.000 0 0.000 376 2.575 0 0.000 3022 3.480

BI

121 2.083

BJ

0 0.000 101 2.004 0 0.000 535 2.728 533 2.727 0 0.000 0 0.000 425 2.628 0 0.000 3 .477 1468 3.157 0 0.000 320 2.505

BL

BM BO

BR BS

BT BU BW

BY CA

cc CE

62 1.792 9 .954 200 2.301 27 1.431 0 0.000 0 0.000 7 .845 0 0.000 68 1.833 3 .477 0 0.000 25 1.398 69 1.839 58 1.763 42 1.623 12 1.079 0 0.000 0 0.000 36 1.556 167 2.223 44 1.643

11 1.041 3 .477 282 2.450 41 1.613 53 1.724 85 1.929 155 2.190 106 2.025

0 0.000 490 2.690 18 1.255 92 1.964 33 1.519 8 .903 31 1.491 24 1.380 7 .845 0 0.000 436 2.639 0 0.000 567 2.754

4TH

5TH

SUM

3 .477 3 .477 472 2.674 3 .477 58 1.763 8 .903 755 2.884 21 1.322 0 0.000 266 2.425 0 0.000 152 2.182 0 0.000 0 0.000 16 1.204 0 0.000 0 0.000 0 0.000 115 2.064 4 .602 929 2.968

10 1.000 20 1.301 325 2.512 0 0.000 0 0.000 0 0.000 3 .477 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 16 1.204 0 0.000 0 0.000 0 0.000 60 1.778 45 1.653 0 0.000 1267 3.103

117 2.068 35 1.544 1279 3.107 71 1.851 4 87 2.688 93 1.968 3952 3.597 248 2.394 68 1.833 860 2.934 18 1.255 804 2.905 635 2.803 82 1.914 89 1.949 461 2.664 7 .845 53 1.799 2101 3.322 171 2.233 3127 3.495

APPENDIX 5.2

207

BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 6 BIGRAM POSITION 3RD 2N D 1ST CH CI CK CL CN CO CR

cs CT

cu CY DA DD DE DF DG DH DI DJ DL DM

1371 3.137 177 2.248 0 0.000 438 2.641 0 0.000 2059 3.314 311 2.493 0 0.000 0 0.000 83 1.919 10 1.000 329 2.517 0 0.000 1235 3.092 0 0.000 0 0.000 0 0.000 392 2.593 0 0.000 0 0.000 0 0.000

546 2.737 0 0.000 0 0.000 0 0.000 0 0.000 35 1.544 370 2.568 0 0.000 555 2.144 0 0.000 0 0.000 0 0.000 22 1.342 16 1.204 0 0.000 5 .699 4 .602 87 1.940 16 1.204 0 0.000 10 1.000

174 2.241 538 2.731 468 2.670 23 1.362 15 1.176 998 2.999 119 2.076 0 0.000 297 2.473 130 2.114 0 0.000 19 1.279 310 2.491 604 2.781 3 .477 123 2.090 0 0.000 379 2.579 0 0.000 0 0.000 3 .477

4TH

5TH

SUM

13 1.114 46 1.663 186 2.270 102 2.009 0 0.000 60 1.778 0 0.000 0 0.000 5 .699 33 1.519 0 0.000 2 54 2.405 0 0.000 1285 3.109 0 0.000 105 2.021 8 .903 101 2.004 0 0.000 469 2.671 0 0.000

779 2.892 0 0.000 167 2.223 0 0.000 0 0.000 27 1.431 0 0.000 51 1.708 761 2.881 0 0.000 287 2.458 45 1.653 0 0.000 460 2.663 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

2883 3.460 761 2.881 821 2.914 563 2.751 15 1.176 3179 3.502 800 2.903 51 1.708 1618 3.209 246 2.391 297 2.473 647 2.811 332 2.521 3600 3.556 3 .477 233 2.367 12 1.079 959 2.982 16 1.204 469 2.671 13 1.114

CHAPTER 5

208

BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 6 B I G R A M POSITION DN

DO DR

DS

DT

DU DV

DW DY EA

EB EC ED

EE

EF EG EH EI

EJ EK

EL

1ST

2N D

0 0.000 293 2.467 236 2.373 0 0.000 0 0.000 649 2.812 0 0.000 12 1.079 0 0.000 231 2.364 0 0.000

0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 23 1.362 66 1.820 45 1.653 0 0.000 1875 3.273 74 1.869 1638 3.214 131 2.117 777 2.890 1180 3.072 4 28 2.631 304 2.483 196 2.292 10 1.000 0 0.000 586 2.768

15 1.176 134 2.127 0 0.000 358 2.554 0 0.000 0 0.000 344 2.537 0 0.000 0 0.000 89 1.949

3RD 20 1.301 8 .903 15 1.176 56 1.748 5 .699 a8 1.944 0 0.000 15 1.176 0 0.000 410 2.613 11 1.041 109 2.037 282 2.450 274 2.438 85 1.929 11 1.041 0 0.000 111 2.045 0 0.000 24 1.380 163 2.212

4TH

5TH

SUM

0 0.000 398 2.600 11 1.041 3 .477 0 0.000 4 .602 0 0.000 0 0.000 0 0.000 593 2.773 8 .903 743 2.871

0 0.000 0 0.000 0 0.000 535 2.728 10 1.000 0 0.000 0 0.000 0 0.000 234 2.369 6 .778 0 0.000 0 0.000

20 1.301 699 2.844 262 2.418 594 2.774 15 1.176 764 2.883 66 1.820 72 1.857 234 2.369 3115 3.493 93 1.968 2505 3.399

35 1.929 703 2.847 6 .778 3 .477 0 0.000 3 .477 0 0.000 18 1.255 1509 3.179

8585 3.934 224 2.350 130 2.114 0 0.000 0 0.000 13 1.114 0 0.000 5 .699 325 2.512

9217 3.965 1978 3.296 1759 3.245 442 2.645 304 2.483 657 2.824 10 1.000 47 1.672 2672 3.427

209

APPENDIX 5 . 2 B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 6 B I G R A M POSITION

EM EN

EO

EP EQ ER

ES ET EU

EV EW EX EY

EZ FA FE FF FI FL FO FR

1ST

2ND

3RD

4TH

5TH

SUM

62 1.792 886 2.947 0 0.000 0 0.000 23 1.362 73 1.863 144 2.158 32 1.505 143 2.155 126 2.100 0 0.000 649 2.812

685 2.836 936 2.971 976 2.989 343 2.535 0 0.000 1551 3.191 769 2.886 1071 3.030 9 .954 312 2.494 177 2.248 97 1.987

48 1.681 1274 3.105 3 .477 314 2.497 0 0.000 1461 3.165 601 2.779 130 2.114 32 1.505 28 1.447 24 1.380 0 0.000

4 35 2.638 1099 3.041 12 1.079 35 1.544 0 0.000 6964 3.843 3735 3.572

4 .602 0 0.000 997 2.999 165 2.217 0 0.000 803 2.905 218 2.338 926 2.967 573 2.758

183 2.262 0 0.000 0 0.000 0 0.000 791 2.898 0 0.000 10 1.000 0 0.000 102 2.009

360 2.556 803 2.905 129 2.111 76 1.881 0 0.000 2 52 2.401 82 1.914 2 53 2.403 0 0.000 63 1.799 33 1.519 10 1.000 7 .845

0 0.000 33 1.519 0 0.000 185 2.267 12 1.079 51 1.708 12 1.079 0 0.000 0 0.000

284 2.453

1590 3.201 4998 3.699 1120 3.049 768 2.885 23 1.362 10301 4.013 5331 3.727 2650 3.423 188 2.274 529 2.723 321 2.507 760 2.881 478 2.679

0 0.000 0 0.000 6 .778 9 . 9 54 0 0.000 0 0.000 0 0.000 0 0.000

33 1.519 1054 3.023 790 2.898 974 2.989 1155 3.063 271 2.433 2182 3.339 727 2.862

0 0.000 57 1.756 434 2.637 162 2.210 301 2.479 31 1.491 1256 3.099 52 1.716

1164 3.066 4 .602 0 0.000 87 1.940 4 .602

210

CHAPTER 5


FS FT FU FY GA

GE GG GH GI GL

GM GN GO GR

GS GT GU

GY HA HE

HI

1ST

2ND

3RD

4TH

5TH

SUM

0 0.000 0 0.000 271 2.433 0 0.000 196 2.292 322 2.508 0 0.000 16 1.204 138 2.140 88 1.944 0 0.000 0 0.000 119 2.076 661 2.820 0 0.000 0 0.000 172 2.236 0 0.000 834 2.921 493 2.693 316 2.500

0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 100 2.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 19 1.279

9 .954 99 1.996 23 1.362 0 0.000 129 2.111 124 2.093 117 2.068 544 2.736 226 2.354 11 1.041 0 0.000

0 0.000 26 1.415 61 1.785 0 0.000 86 1.934 1851 3.022 0 0.000 722 2.859 150 2.176 205 2.312 4 .602 0 0.000 33 1.519 23 1.362 0 0.000 116 2.064 110 2.041 0 0.000 29 1.462 1739 3.240 370 2.568

23 1.362 0 0.000 0 0.000 19 1.279 0 0.000 844 2.926 0 0.000 872 2.941

32 1.505 125 2.097 355 2.550 19 1.279 411 2.614 2441 3.388 117 2.068 2154 3.333 514 2.711 304 2.483 4 .602 275 2.439 191 2.281 910 2.959 462 2.665 116 2.064 583 2.766 112 2.049 1763 3.246 2976 3.474 1559 3.193

0 0.000 92 1.964 0 0.000 0 0.000 0 0.000 0 0.000 848 2.928 328 2.516 586 2.768

124 2.093 36 1.556 134 2.127 0 0.000 0 0.000 301 2.479 0 0.000 34 1.531 399 2.601 287 2.458

0 0.000 0 0.000 0 0.000 132 2.121 3 .477 0 0.000 462 2.665 0 0.000 0 0.000 112 2.049 18 1.255 17 1.230 0 0.000

APPENDIX 5.2

211

BIGRAM F R E Q U E N C I E S F O R WORDS OF LETTER L E N G T H 6 BIGRAM P O S I T I O N HL HM HN HO HR HS HT

HU HW HY IA IB IC ID IE IF IG I1 IK IL IM

1ST

2ND

3RD

4TH

5TH

SUM

0 0.000 0 0.000 0 0.000 463 2.666 0 0.000 0 0.000 0 0.000 204 2.310 0 0.000 0 0.000 0 0.000 0 0.000

0 0.000 0 0.000 0 0.000 1991 3.299 361 2.558 0 0.000 0 0.000 359 2.555 3 .477 22 1.342 56 1.748 43 1.633

0 0.000 0 0.000 43 1.633 524 2.719 5 .699 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 43 1.633 25 1.398

99 1.996 7 .845 0 0.000

0 0.000 22 1.342 0 0.000 0 0.000 0 0.000 273 2.436 703 2.847 0 0.000 0 0.000 63 1.799 99 1.996 0 0.000

99 1.996 29 1.462 43 1.633 3219 3.508 366 2.563 273 2.436 947 2.976 618 2.791 3 .477 85 1.929 733 2.865 68 1.833

3 .477 16 1.204 0 0.000 0 0.000 19 1.279 0 0.000 0 0.000 0 0.000 138 2.140

284 2.453 322 2.508 253 2.403 100 2.000 870 2.940 0 0.000

169 2.228 195 2.290 203 2.307 32 1.505 452 2.665 7 .845

739 2.869 168 2.225 46 1.663 0 0.000 8 .903 16 1.204

2255 3.353 1049 3.021 1549 3.190 167 2.223 1491 3.173 23 1.362

169 2.228 548 2.739 421 2.624

0 0.000 346 2.539 107 2.029

0 0.000 142 2.152 27 1.431

261 2.417 1606 3.206 790 2.898

241 2.382 0 0.000 0 0.000 244 2.387 55 1.740 0 0.000 0 0.000 535 2.728 0 0.000 1060 3.025 348 2.542 1047 3.020 35 1.544 132 2.121 0 0.000 92 1.964 570 2.756 97 1.987

212

CHAPTER 5

BIGRAM F R E Q U E N C I E S F O R WORDS O F L E T T E R LENGTH 6 BIGRAM P O S I T I O N 3 RD 1ST 2ND

4TH

5TH

SUM.

873 2.941 0 0.000

828 2.918 18 1.255

916 2.962 36 1.556

4190 3.622 1100 3.041

9 15 2.961 31 1.491

7722 3.888 1185 3.074

IP

0 0.000

29 1.462

5 .699

33 1.519

34 1.531

101 2.004

IQ

0 0.000

91 1.959

58 1.763

0 0.000

0 0.000

149 2.173

IR

17 1.230

IS

298 2.474

389 2.590 800 2.903

325 2.512 392 2.593

406 2.609 480 2.681

73 1.863 167 2.223

1210 3.083 2137 3.330

IT

304 2.483

1757 3.245

901 2.955

235 2.371

444 2.647

3641 3.561

IU

0 0.000

0 0.000

0 0.000

108 2.033

0 0.000

108 2.033

IV

0 0.000 0 0.000

394 2.595 21 1.322

122 2.086 0 0.000

208 2.318

724 2.860

0 0.000

0 0.000 0 0.000

I2

0 0.00Q

3 .477

30 1.477

0 0.000

0 0.000

33 1.519

JA

50 1.699

0 0.000

0 0.000

0 0.000

0 0.000

50 1.699

JE

119 2.076

0 0.000

84 1.924

0 0.000

0 0.000

203 2.307

JO

176 2.246 196 2.292 31 1.491

0 0.000 0 0.000 0 0.000

13 1.114 43 1.633 0 0.000

0 0.000 0 0.000 22 1.342

189 2.276 239 2.378

KE

6 .778

16 1.204

176 2.246

0 0.000 0 0.000 0 0.000 1927 3.285

127 2.104

2252 3.353

KI

152 2.182

57 1.756

543 2.735

12

1.079

0 0.000

764 2.883

0 0.000 25 1.398 11 1.041

0 0.000 0 0.000

7 .845 0 0.000 6 .778

42 1.623 0 0.000 7 .845

Q 0.000 0 0.000 0 0.000

49 1.690 25 1.398 24 1.380

IN I0

IX

JU KA

KL KN KO

0

0.000

21 1.322

53 1.724

213

APPENDIX 5.2 B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 6 B I G R A M POSITION 2ND 1ST 3RD

KS KU KY

LA LB

LD LE

LF LG LI LK LL LM LN

LO

LP LS LT LU

LV LW

0 0.000 0 0.000 0 0.000 518 2.714 0 0.000 0 0.000 718 2.856

0 0.000 0 0.000 0 0.000 914 2.961 47 1.672 28 1.447 210 2.322

0 0.000 0 0.000 0 0.000 321 2.507 0 0.000 189 2.276

0 0 * 000 0 0.000 1605 3.205 0 0.000 0 0.000

52 1.716 0 0.000 173 2.238 0 0.000 78 1.892

0 0.000

0 0.000 0 0.000 978 2.990 0 0.000

432 2.635 0 0.000 536 2.729 0 0.000

0 0.000 0 0.000 81 1.908 0 0.000 0 0.000

0 0.000 0 0.000 57 1.756 0 0.000 4 58 2.661

316 2.500

10 1.000 773 2.888 234 2.369 1471 3.168 117 2.068

11 1.041 193 2.286 79 1.898 78 1.892 144 2.158 413 2.616 68 1.833 0 0.000

4TH

5TH

SUM

0 0.000 14 1.146 0 0.000 155 2.190 0 0.000 93 1.968 1635 3.214 0 0.000 0 0.000 577 2.761 0 0.000

360 2.556 0 0.000 32 1.505 19 1.279 0 0.000 1004 3.002 3499 3.544 4 54 2.657

360 2.556 14 1.146 32 1.505 1927 3.285 47 1.672 1314 3.119 6378 3.805

0 0.000 0 0.000 0 0.000

10 1.000 3128 3.495 234 2.369

391 2.592

81 1.908

2021 3.306

0 0.000 0 0.000 342 2.534 0 0.000

0 0.000 0 0.000 13 1.114 0 0.000 500 2.699

549 2.740 11 1.041 2062 3.314 79 1.898 578 2.762 597 2.176 555 2.744 121 2.083 458 2.661

0 0.000 194 2.288 4 .602 53 1.724 0 0.000

259 2.413 0 0.000 0 0.000 0 0.000

506 2.704

214

CHAPTER 5


B I G R A M POSITION ~~~

LY MA

MB ME MI

ML MM MN

MO

MP MS MT MU

MY NA

NB NC

ND

NE

NF

NG

1ST

2ND

3RD

4TH

5TH

SUM

18 1.255 1493 3.174 0 0.000 801 2.904 436 2.639 0 0.000 0 0.000 0 0.000 1637 3.214 0 0.000 0 0.000 0 0.000

43 1.633 48 1.681 12 1.079 27 1.431 85 1.929 0 0.000 5 .699 0 0.000 223 2.348 135 2.130 0 0.000 0 0.000

0 0.000 346 2.539 788 2.897 420 2.623 613 2.787 7 .845 433 2.636

4 .602 540 2.732 12 1.079 988 2.995 194 2.288 79 1.898 0 0.000

2892 3.461 28 1.447 0 0.000 1022 3.009 7 .845 0 0.000 0 0.000

2957 3.471 2455 3.390 812 2.910 3258 3.513 1335 3.125 86 1.934 4 38 2.641

105 2.021

133 2.124

0 0.000 0 0.000 120 2.079 0 0.000

2815 3.449 699 2.844 136 2.134 28 1.447

215 2.332 136 2.134 512 2.709 0 0.000 0 0.000 0 0.000 519 2.715 0 0.000

9 .954

37 1.568 0 0.000 193 2.286 0 0.000 157 2.196 717 2.856 236 2.373 6 .778 773 2.888

0 0.000 15 1.176 51 1.708 0 0.000 0 0.000 2237 3.350

268 2.428 155 2.190 935 2.971

0 0.000

4 .602 113 2.053

4 .602 216 2.334 297 2.473 128 2.107 35

1.544

107 2.029

19 1.279 7 07 2.849 532 2.726 10 1.000 0 0.000

9 .954 248 2.394 32 1.505 6 .778 28 1.447 7 .845 0 0.000 66 1.820 0 0.000 544 2.736 284 2.453 1362 3.134 0 0.000 765 2.884

447 2.650 0 0.000 3776 3.577

4 .602 917 2.962 3535 3.548 2692 3.430 41 1.613 5421 3.734

APPENDIX 5.2

215

BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 6 BIGRAM POSITION 1ST 2N D 3RD NI NJ NK NL NM NN NO NP NR NS

NT NU NV NW NY NZ OA

OB

oc OD OE

68 1.833 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 450 2.653 0 0.000 0 0.000 0 0.000 0 0.000 494 2.694 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 114 2.057 46 1.663 3 .477 0 0.000

673 2.828 43 1.633 10 1.000 165 2.217 0 0.000 113 2.053 430 2.633 9 .954 25 1.398 445 2.648 231 2.364 3 .477 35 1.544 12 1.079 206 2.314 6 .778 131 2.117 214 2.330 624 2.795 4 36 2.639 119 2.076

380 2.580 0 0.000 72 1.857 6 .778 3 .477 582 2.765 72 1.857 0 0.000 22 1.342 118 2.072 955 2.980 176 2.246 51 1.708 4 .602 12 1.079 0 0.000 28 1.447 7 .845 67 1.826 71 1.851 0 0.000

4TH

5TH

SUM

71 1.851 0 0.000 100 2.000 75 1.875 0 0.000 67 1.826 286 2.456 0 0.000 0 0.000 0 0.000 7 51 2.876 63 1.799 0 0.000 0 0.000 0 0.000 17 1.230 116 2.064 0 0.000 3 .477 123 2.090 32 1.505

9 .954 0 0.000

1201 3.080 43 1.633 187 2.272 246 2.391 3 .477 762 2.882 1238 3.093 9 .954 47 1.672 870 2.940 3023 3.480 736 2.867 86 1.934 16 1.204 305 2.484 23 1.362 275 2.439 335 2.525 740 2.869 1040 3.017 163 2.212

5

.699 0 0.000 0 Q.OOO 0 0.000 0 0.000 0 0.000 0 0.000 3 07 2.487 1086 3.036 0 0.000 0 0.000 0 0.000 87 1.940 0 0.000 0 0.000 0 0.000 0 0.000 4 07 2.610 12 1.079

216

CHAPTER 5

BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 6 BIGRAM POSITION 2ND 1ST 3 RD

OF OG

OH 01 OK OL OM ON 00

OP OR 0s

OT

ou ov OW

ox OY 02

PA PE

313 2.496 0 0.000 0 0.000 0 0.000 0 0.000 21 1.322 0 0.000 8 .903 0 0.000 197 2.294 178 2.250 0 0.000 323 2.509

125 2.097 9 .954 30 1.477 314 2.497 10 1.000 1189 3.075 781 2.893

82 1.914 8 .903 38 1.580 61 1.785 6 .778 0 0.000 849 2.929 1450 3.161

4TH

STH

SUM

0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 598 2.777 223 2.348 2267 3.355 0 0.000 22 1.342 762 2.882 35 1.544 288 2.459

466 2.668 16 1.204 30 1.477 460 2.663 580 2.763 2007 3.303 1664 3.221 4259 3.629 1311 3.118 1501 3.176 4956 3.695 1534 3.186 1643 3.216

0 0.000 0 0.000 573 2.758 3 .477 31 1.491 0 0.000 0 0.000 197 2.294

849 2.929

28 1.447 7 .845 0 0.000 116 2.064 531 2.725 114 2.057 179 2.253 105 2.021

592 2.772 104 2.017 1523 3.183 428 2.631 853 2.931

193 2.286 1007 3.003 392 2.593 268 2.428 72 1.857

0 0.000 0 0.000 0 0.000 30 1.477 39 1.591 85 1.929 481 2.682 1030 3.013 526 2.721 171 2.233 2101 3.322 803 2.905 107 2.029

1606 3.206 407 2.610 598 2.777 0 0.000 26 1.415 18 1.255 44 1.643 278 2.444

2869 3.458 130 2.114 504 2.702 0 0.000 0 0.000 27 1.431 127 2.104 511 2.708

123 2.090 62 1.792 83 1.919 0 0.000 10 1.000 0 0.000 0 0.000 639 2.806

4680 3.670 607 2.783 1796 3.254 64 1.806 73 1.863 45 1.653 1020 3.009 3075 3.488

APPENDIX 5 . 2

217


PH PI PK PL PO PP PR PS

PT PU PW PY

Qu RA RB RC

RD RE

RG

RH RI

1ST

2ND

3RD

4TH

5TH

SUM

108 2.033 313 2.496 0 0.000 688 2.838 1075 3.031 0 0.000 610 2.785

35 1.544 193 2.286 6 .778 3 .477 101 2.004 195 2.290 239 2.378

222 2.346 714 2.854 9 .954 2 267 3.355 1455 3.163 496 2.695 855 2.932

11 1.041 22 1.342 0 0.000 27 1.431 0 0.000 166 2.220

15 1.176 52 1.716 0 0.000 1564 3.194 46 1.663 3 .471 0 0.000 7 .845 0 0.000 75 1.875 0 0.000 0 0.000 64 1.806

55 1.740 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

7 .845 0 0.000 727 2.862 0 0.000 0 0.000

9 .954 156 2.193 3 .477 12 1.079 233 2.367 298 2.474 6 .778 7 .845 19 1.279 17 1.230 0 0.000 0 0.000 91 1.959

211 2.324 298 2.474 0 0.000 0 0.000 25 1.398 0 0.000

269 2.430 132 2.121 404 2.606 360 2.556 1436 3.157 417 2.620 0 0.000 1756 3.245

41 1.613 44 1.643 528 2.723 118 2.072 909 2.959 381 2.581 0 0.000 268 2.428

40 1.602 40 1.602 0 0.000 875 2.942 2364 3.374 0 0.000 0 0.000 0 0.000

243 2.386 3 39 2.530 819 2.913 27 1.431 25 1.398 391 2.592 1841 3.265 225 2.352 953 2.979 1426 3.154 8061 3.906 889 2.949 30 1.477 3567 3.552

70 1.845 817 2.912 0 0.000 0 0.000 0 0.000 2643 3.422 47

0.000 30 1.477 312 2.494

674 2.829 9 .954 21 1.322 73 1.863 709 2.851 91 1.959 0 0.000 1231 3.090

218

CHAPTER 5


RK RL RM RN RO

RP RR

RS RT RU RV

RY SA SC SD SE SH SI SK

SL SM

1ST

2ND

3RD

4TH

5TH

SUM

0 0.000 0 0.000 0 0.000 0 0.000 254 2.405 0 0.000 0 0.000 0 0.000 0 0.000 220 2.342 0 0.000 0 0.000 530 2.724 722 2.859 0 0.000 1846 3.266 1464 3.166 836 2.922

0 0.000 0 0.000 15 1.176 30 1.477 1520 3.182 0 0.000 100 2.000 0 0.000 154 2.188 85 1.929 4 .602 207 2.316 11 1.041 74 1.869 0 0.000 58 1.763 6 .778 0 0.000 67 1.826 196 2.292 0 0.000

542 2.734 140 2.146 745 2.872 561 2.749 953 2.979 50 1.699 311 2.493 340 2.531 286 2.456 124 2.093 293 2.467 0 0.000 35 1.544 220 2.342 44 1.643 677 2.831 276 2.441 897 2.953

15 1.176 237 2.375 14 1.146 10 1.000 199 2.299 0 0.000 42 1.623 489 2.689 363 2.560 22 1.342 0 0.000 0 0.000 61 1.785 4 .602 0 0.000 1384 3.141 3 .477 228 2.358

44 1.643 0 0.000 49 1.690 399 2.601 32 1.505 0 0.000 0 0.000 1200 3.079 602 2.780 0 0.000 0 0.000 543 2.735 0 0.000 0 0.000 0 0.000 819 2.913 188 2.274 0 0.000

601 2.779 377 2.576 823 2.915 1000 3.000 2958 3.471 50 1.699 453 2.656 2029 3.307 1405 3.148 451 2.654 297 2.473 750 2.875 637 2.804 1020 3.009 44 1.643 4784 3.680 1937 3.287 1961 3.292

25 1.398 3 .477 34 1.531

45 1.653 0 0.000 13 1.114

0 0.000 0 0.000 13 1.114

210 2.322 490 2.690 206 2.314

73 1.863 291 2.464 146 2.164

219

APPENDIX 5.2 BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 6 BIGRAM POSITION 3RD 1ST 2ND

SN SO

SP SQ

SR

ss ST SU

sw SY

TA TC TE TF TH TI TL

TM

TO TP

TR

36 1.556 886 2.947 698 2.844 143 2.155 0 0.000 0 0.000 2484 3.395 704 2.848 83 1.919 481 2.682 519 2.715 0 0.000 203 2.307 0 0.000 1419 3.152 145 2.161 0 0.000 0 0.000 508 2.706 0 0.000 614 2.788

0 0.000 0 0.000 56 1.748 0 0.000 15 1.176 313 2.496 59 1.771 0 0.000 0 0.000 7 .845 1251 3.097 0 0.000 57 1.756 0 0.000 363 2.560 31 1.491 0 0.0011 7 .845 202 2.305 0 0.000 807 2.948

0 0.000 25 1.398 21 1.322 0 0.000 0 0.000 562 2.750 1132 3.054 607 2.783 152 2.182 0 0.000 416 2.619 0 0.000 505 2.703 16 1.204 1739 3.240 1352 3.131 50 1.699 0 0.000 74 1.869 35 1.544 63 1.799

4TH

5TH

SUM

0 0.000 817 2.912 0 0.000 0 0.000

0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 565 2.752 1104 3.043 0 0.000 0 0.000 28 1.447 38 1.580 0 0.000 380 2.580 0 0.000 637 2.804 0 0.000 0 0.000 0 0.000 54 1.732 0 0.000 0 0.000

36 1.556 1728 3.238 775 2.889 143 2.155 18 1.255 1440 3.158 4921 3.692 1395 3.145 235 2.371 516 2.713 2366 3.374 76 1.881 5502 3.741 16 1.204 4493 3.653 1725 3.237 1512 3.180 7 .a45 1523 3.183 35 1.544 1694 3.229

3

.477 0 0.000 142 2.152 84 1.924 0 0.000 0 0.000 142 2.152 76 1.881 4357 3.639 0 0.000 335 2.525 197 2.294 1462 3.165 0 B.000 685 2.836 0 0.000 130 2.114

220

CHAPTER 5


BIGRAM POSITION 2ND 1ST 3RD

TS TT TU TW TY UA

UB

uc UD

UE UF UG

UI UL UM ON

uo UP UR

us UT

0 0.000 0 0.000 370 2.568 144 2.158 7 .845 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 874 2.942 0 0.000 74 1.869 31 1.491 69 1.839 31 1.491

304 2.483 199 2.299 183 2.013 0 0.000 23 1.362 44 1.643 577 2.761 52 1.716 203 2.307 96 1.982 59 1.771 134 2.127 133 2.124 209 2.320 7 59 2.880 333 2.522 31 1.491 188 2.274 1544 3.189 316 2.500 492 2.692

58 1.763 2414 3.383 809 2.908 0 0.000 0 0.000 175 2.243 82 1.914 29 1.462 73 1.863 5 .699 4 .602 316 2.500 44 1.643 47 1.672 40 1.602 352 2.547 0 0.000 150 2.176 1086 3.036 356 2.551 41 1.613

4TH

5TH

SUM

0 0.000 118 2.072 148 2.170 0 0.000 8 .903 374 2.573 7 .845 145 2.161

1618 3.209 2736 3.437 1430 3.155 144 2.158 817 2.912 597 2.776 666 2.823 226 2.354

54 1.732 394 2.595 4 .602 883 2.946

1256 3.099 5 .699 0 0.000 0 0.000 779 2.892 4 .602 0 0.000 0 0.000 4 .602 343 2.535 0 0.000 0 0.000

48 1.681 1145 3.059 311 2.493 934 2.970 43 1.633 162 2.210 1078 3.033 177 2.248 149 2.173

0 0.000 64 1.806 128 2.107 4 .602 0 0.000 14 1.146 62 1.792 338 2.529 62 1.792

334 2.524 838 2.923 67 1.826 1333 3.125 225 2.352 1465 3.166 1238 3.093 2497 3.397 74 1.869 588 2.769 3801 3.580 1256 3.099 775 2.889

APPENDIX 5 . 2

221

BI G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 6 B I G R A M POSITION

uu

ux UY

uz VA

VE VI VO

vu WA

WB WD

WE

WH WI WL WM WN

WO WR

ws

1ST

2ND

3RD

4TH

5TH

SUM

0 0.000 0 0.000 0 0.000 0 0.000

0 0.000 27 1.431 35 1.544 20 1.301 0 0.000 163 2.212 0 0.000 20 1.301 0 0.000 36 1.556 0 0.000 0 0.000 147 2.167 4 .602 79 1.898 0 0.000 0 0.000 38 1.580 4 .602 0 0.000 0 0.000

0 0.000 0 0.000 0 0.000 0 0.000 48 1.681 322 2.508 1185 3.074

20 1.301 0 0.000 0 0.000 0 0.000

0 0.000 4 .602 0 0.000 0 0.000 17 1.230 347 2.540 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 8 .903 0 0.000 0 0.000 0 0.000 3 .477 0 0.000

20 1.301 31 1.491 35 544 20 301 467 669 884 3.275 1507 3.178 345 2.538 7 ,845 2038 3.309 16 1.204 48 1.681

383 2.583 123 2.090 309 2.490 251 2.400 7 .845 898 2.953 0 0.000 0 0.000 226 2.354 90 1.954 910 2.959 0 0.000 0 0.000 0 0.000 341 2.533 180 2.255 0 0.000

51 1.708 0 0.000 1039 3.017 16 1.204 28 1.447 145 2.161 0 0.000 87 1.940 0 0.000 10 1.000 5 .699 0 0.000 0 0.000 3 .477

19 1.279 929 2.968 13 1.114 23 1.362 0 0.000

65 1.813 0 0.000 12 1.079 418 2.621 0 0.000 7 .845 115 2.061 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

51 1.708 0 0.000 0 0.000 48 1.681

936 2.971 94 1.973 1083 3.035 118 2.072 10 1.000 94 1.973 345 2.538 180 2.255 51 1.708

222

CHAPTER 5


WT WY XA

xc XE

XF XI XL

xo XP XT

xu

1ST

2ND

3RD

4TH

5TH

SUM

0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

0 0.000 0 0.000 0 0.000 276 2.441 5 .699 18 1.255 42 1.623

161 2.207 43 1.633 9 .954 276 2.441

0 0.000 11 1.041 169 2.228 146 2.164 0 0.000 43 1.633 0 0.000 7 .845 5 .699 4 .602 0 0.000 0 0.000 0 0.000 0 0.000

17 1.230 7 .845 6 -778 15 1.176 43 1.633 20 1.301 435 2.638 49 1.690

155 2.190 0 0.000 0 0.000 0 0.000 13 1.114 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 332 2.521 0 0.000 0 0.000 0 0.000 0 0.000

0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

6 .778 43 1.633 9 .954 0 0.000 0 0.000 0 0.000 49 1.690 6 .778 0 0.000 0 0.000 10 1.000 80 1.903 0 0.000

XY

0 0.000

YA

26 1.415 0 0.000 0 a.OOO 89 1.949

YC YD YE

YG YH

YI YL

0 0.000 0 0.000 7 .845 0 0.000

0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 3 .477 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

18 1.255 18 1.255 91 1.959 6 .778 11 1.041 169 2.228 156 2.193 80 1.903 46 1.663 43 1.633 14 1.146 11 1.041 440 2.643 43 1.633 20 1.301 442 2.645 49 1.690

APPENDIX 5 . 2

223


B I G R A M POSITION 1ST 3RD 2N D ~~

YM YN

YO

YP YR

YS YT YW ZA

ZE ZI ZL

0 0.000 0 0.000 18 1.255 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

20

6 .778

ZY

0 0.000 0 0.000

zz

54 1.732 12 1.079 0 0.000 10 1.000 22 1.342 551 2.741 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

9 .954 0 0.000 326 2.513 0 0.000 0 0.000 0 0.000 26 1.415 46 1.663 22 1.342 11 1.041 11 1.041 0 0.000 0 0.000 6 .778 24 1.380

4TH

5TH

SUM

6 .778 0 0.000 12 1.079 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

0 0.000 4 .602 0 0.000 0 0.000 8 .903 482 2.683 0 0.000 0 0.000 17 1.230 47 1.672 0 0.000 0 0.000 0 0.000 6 .778 0 0.000

69 1.839 16 1.204 3 56 2.551 10 1.000 30 1.477 1033 3.014 26 1.415 46 1.663

0 0.000 73 1.863 8 .903 24 1.380 0 0.000 0 0.000 17 1.230

39 1.591 131 2.117 19 1.279 24 1.380 6 .778 12 1.079 41 1.613

224

CHAPTER 5

B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 7 B I G R A M POSITION ~~~

AB

AC AD

AE

AF AG AH A1 AJ AK

AL AM AN

A0 AP AQ AR

AS AT AU

AV

1ST

2ND

3 RD

4TH

5TH

6TH

SUM

178 2.250 356 2.551 285 2.455 0 0.000 150 2.176 629 2.799 0 0.000 34 1.531 0 0.000

101 2.004 521 2.717 87 1.940 4 .602 5 .699 66 1.820 0 0.000 433 2.636

64 1.806 543 2.735 593 2.773 0 0.000 81 1.908 175 2.243 0 0.000 838 2.923

166 2.220 65 1.813 180 2.000 0 0.000 0 0.000 200 2.301 6 .778 270 2.431

5 .699 432 2.635 328 2.516 11 1.041 0 0.000 635 2.803 0 0.000 661 2.820

0 0.000 5 .699 180 2.255 0 0.000 0 0.000 3 .477 0 0.000 0 0.000

514 2.711 1922 3.284 1573 3.197 15 1.176 236 2.373 1708 3.232 6 .778 2236 3.349

0 0.000

0 0.000 40 1.602 185 2.267 40 1.602 1086 3.036 0 0.000 319 2.504 0 0.000 953 2.979 138 2.140

0 0.000 0 0.000 3015 3.479 561 2.749 352 2.547 0 0.000 4 .602 0 0.000 547 2.738 82 1.914

189 2.276 44 1.643 157 2.196

972 2.988 125 2.097 80 1.903

0 0.000 67 1.826 650 2.813 89 1.949 582 2.765 0 0.000 67 1.826 0 0.000 365 2.562 111 2.045 853 2.931 908 2.958 21 1.322

3 .477

1162 3.065 0 0.800 253 2.403 14 1.146 304 2.483 238 2.377

3 .477 4 .602 574 2.759 78 1.892 740 2.869 4 .602 465 2.667 0 0.000 1936 3.287 480 2.681

393 2.594 5 .699 4 .602

32 1.505 3 .477 0 0.000

0 0.000 439 2.642 315 2.498

40 1.602 652 2.814 4 59 2.662 894 2.951 5 .699 232 2.365 4 .602 1160 3.064 555 2.744 477 2.679 3 .477 2 58 2.412

151 2.179 5515 3.742 1542 3.188 4816 3.683 9 .954 1340 3.127 18 1.255 5265 3.721 1604 3.205 2916 3.465 1088 3.037 520 2.716

APPENDIX 5.2

225

BIGRAM F R E Q U E N C I E S F O R W O R D S OF L E T T E R L E N G T H 7 BIGRAM P O S I T I O N 1ST 2N D 3RD AW AX AY A2 BA BB BD BE BI BJ BL BO BR BS BT BU BV BY CA

cc CE

49 1.690 0 0.000 0 0.000 0 0.000 308 2.489 0 0.000 0 0.000 2413 3.383 150 2.176 0 0.000 182 2.260 195 2.290 702 2.846 0 0.000 0 0.000 197 2.294 0 0.000 0 0.000 813 2.910 0 0.000 782 2.893

26 1.415 101 2.004 154 2.188 20 1.301 17 1.230 0 0.000 6 .778 13 1.114 79 1.898 65 1.813 21 1.322 8 .903 11 1.041 95 1.978 0 0.000 0 0.000 92 1.964 0 0.000 45 1.653 157 2.196 26 1.415

85 1.929 0 0.000 202 2.305 33 1.519 50 1.699 63 1.799 8 .903 177 2.248 43 1.633 161 2.207 8 .903 14 1.146 127 2.104 8 .903 0 0.000 31 1.491 0 0.000 0 0 * 000 1059 3.025 108 2.033 153 2.185

4TH

5TH

6TH

SUM

10 1.000 17 1.230 35 1.544 0 0.000 175 2.243 23 1.362 0 0.000 502 2.701 73 1.863 0 0.000 397 2.599 98 1.991 4 .602 0 0.000 9 .954 76 1.881 0 0.000 0 0.000 119 2.076

0 0.000 0 0.000 18 1.255 0 0.000 3 .477 0 0.000 0 0.000 188 2.274 33 1.519 0 0.000 364 2.561 17 1.230

0 0.000 0 0.000 252 2.401 0 0.000 0 0.000 0 0.000 0 0.000 7 .845 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 18 1.255 0 0.000 0 0.000 0 0.000 60 1.778 194 2.288 0 0.000 1291 3.111

170 2.230 118 2.072 661 2.820 53 1.724 553 2.743 86 1.934 14 1.146 3300 3.519 378 2.577 226 2.354 972 2.988 332 2.521 844 2.926 121 2.083 9 .954 304 2.483 92 1.964 66 1.820 2746 3.439 289 2.461 3498 3.544

Q 0.000 711 2.852

0 0.000 0 0.000 0 0.000 0 0.000

Q 0.000 6 .778 516 2.713 24 1.380 535 2.728

226

CHAPTER 5

B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 7 B I G R A M POSITION 1ST 2N D 3RD CH

CI CK

CL CN CO

CQ CR

CS CT

cu CY DA DB DC DD DE

DF DG DH

DI

1075 3.031 94 1.973 0 0.000 748 2.874 0 0.000 2983 3.475 0 0.000 413 2.616 0 0.000 0 0.000 344 2.537 16 1.204 140 2.146 0 0.000 0 0.000 0 0.000 1546 3.189 0 0.000 0 0.000 0 0.000 517 2.713

267 2.427 131 2.117 0 0.000 0 0.000 0 0.000 101 2.004 27 1.431 56 1.748 6 .778 125 2.097 5 .699 0 0.000 18 1.255 0 0.000 0 0.000 81 1.908 10 1.000 0 0.000 0 0.000 5 .699 63 1.799

202 2.305 554 2.744 307 2.487 293 2.467 3 .477 372 2.571 8 .903 49 1.690 0 0.000 719 2.857 145 2.161

5 .699 3 .477 0 0.000 0 0.000 98 1.991 385 2.585 0 0.000 37 1.568 7 .845 285 2.455

4TH

5TH

6TH

SUM

718 2.856 513 2.710 304 2.483 72 1.857 0 0.800 156 2.193 0 0.000 0 0.000 0 0.000 2 34 2.369 94 1.973 0 0.000 40 1.602 9 .954 4 .602 13 1.114 502 2.701 18 1.255 41 1.613 0 0.000 1004 3.002

32 1.505 139 2.143 22 1.342 127 2.104

78 1.892 0 0.000 32 1.505 0 0.000 0 0.000 27 1.431

2372 3.375 1431 3.156 665 2.823 1240 3.093 3 .477 3639 3.561 35 1.544 518 2.714

0

0.000 0 0.000 0 0.000 0 0.000 0 0.000 340 2.531 0 0.000 0 0.000 96 1.982 3 .477 0 0.000 0 0.000 727 2.862 0 0.000 0 0.000 0 0.000 5 .699

(1

0.000 0 0.000 103 2.013 911 2.960 0 0.000 71 1.851 46 1.663 0 0.000 0 0.000 0 0.000 629 2.799 0 0.000 0 0.000 0 0.000 0 0.000

109 2.037 2329 3.367 588 2.769 92 1.964 343 2.535 12 1.079 4 .602 192 2.283 3799 3.580 18 1.255 78 1.892 12 1.079 1874 3.273

227

APPENDIX 5 . 2 B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 7 B I G R A M POSITION 2ND 1ST 3RD

DJ DL

DM DN

DO DR

DS DT

DU DV

DW DY

0 0.000 0 0.000 0 0.000 0 0.000 218 2.338 372 2.571 0 0.000 0 0.000 32 1.505 0 0.000 0 0.000 21 1.322

EA

231 2.364

EB

0 0.000 85 1.929 70 1.845 0 0.000 236 2.373 0 0.000 0 0.000 0 0.000

EC ED EE

EF EG EH EI

6 .778 0 0.000 20 1.301 0 0.000 45 1.653 0 0.000 0 0.000 0 0.000 7 .845 110 2.041 3 .477 4 .602 2239 3.350 28 1.447 1753 3.244 614 2.788 560 2.748 386 2.587 261 2.417 48 1.681 243 2.386

0 0.000 20 1.301 0 0.000 11 1.041 35 1.544 129 2.111 5 .699 4 .602 138 2.140 0 0.000 11 1.041 0 0.000 934 2.970 4 .602 4 54 2.657 6B 1.778 226 2.354 8 .903 18 1.255 0 0.000 28 1.447

4TH

5TH

6TH

SUM

0 0.000 78 1.892 0 0.000 4 .602 116 2.064 178 2.250 0 0.000 0 0.000 251 2.400 0 0.000 5 .699 0 0.000

0 0.000 136 2.134 13 1.114 0 0.000 199 2.299 5 .699 0 (jl. 0 0 0 7 .845

0 0.000 0 0.000 0 0.000 0 0.000 7 .845 0 0.000 8 67 2.938 0 0.000 0 0.000 0 0.000 0 0.000 510 2.708 0 0.000 0 0.000 0 0.000 7760 3.890 28 1.447 0 0.000 0 0.000 0 0.000 0 0.000

6 .778 234 2.369 33 1.519 15 1.176 620 2.792 684 2.835 872 2.941 11 1.041

683 2.834 0 0.000 336 2.526 159 2.201 105 2.821 203 2.307 32 1.505 72 1.857 251 2.400

11 1.041 0 0.000 0 0.000 0 0.000 364 2.561 52 1.716 6 40 2.806 210 2.322 919 2.963 23 1.362 267 2.427 0 0.000 35 1.544

439 2.642 110 2.041 19 1.279 535 2.728 4451 3.648 84 1.924 3268 3.514 8873 3.948 1838 3.264 8 56 2.932 578 2.762 120 2.079 5 57 2.746

228

CHAPTER 5

BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7 BIGRAM POSITION 2N D 1ST 3 RD

EJ EK EL EM EN

EO

EP EQ ER ES ET EU EV EW EX

EY EZ

FA FE FF FI

0 0.000 0 0.000 139 2.143 168 2.225 747 2.873 0 0.000 12 1.079 70 1.845 37 1.568 45 1.653 . 58 1.763 0 0.000 205 2.312 0 0.000 954 2.980 11 1.041 0 0.000 674 2.829 554 2.744 0 0.000 707 2.849

4TH

5TH

6TH

SUM

11 1.041 74 1.869 2714 3.434 1760 3.246 6658 3.823 2 47 2.393 557 2.746 205 2.312 11577 4.064 5936 3.773 3027 3.481 96 1.982

0 0.000 0 0.000 1007 3.003 270 2.431 1505 3.178 27 1.431 85 1.929 0 0.000 2492 3.397 1100 3.041 693 2.841 36 1.556 264 2.422 9 .954 38 1.580 26 1.415 11 1.041 7 .845

0 0.000 0 0.000 127 2.104

111 2.045 32 1.505 0 0.000 3 .477 0 0.000 95 1.978

0 0.000 0 0.000 200 2.301 146 2.164 1159 3.064 123 2.090 20 1.301 0 0.000 2156 3.334 59 1.771 147 2.167 10 1.000 621 2.793 47 1.672 0 0.000 0 0.000 3 .477 3 18 2.502

403 2.605 59 1.771 231 2.364

94 1.973 101 2.004 98 1.991

17 1.230 0 0.000 166 2.220

0 0.000 20 1.301 0 0.000

11 1.041 0 0.000 869 2.939 696 2.843 1751 3.243 97 1.987 265 2.423 135 2.130 1985 3.298 1214 3.084 1557 3.192 50 1.699

0 0.000 74 1.869 372 2.571 167 2.223 291 2.464 0 0.000 175 2.243 0 0.000 761 2.881 574 2.759 476 2.678 0 0.000

766 2.884 48 1.681 57 1.826 12 1.079 0 0.000 0 0.000 0 0.000 595 2.775 0 0.000

313 2.496 1205 3.081 0 0.000 0 0.000 0 0.000 4146 3.618 2944 3.469 96 1.982 0 0.000 0 0.000 4 .602 91 1.959 121 2.083 0 0.000 0 0.000

1967 3.294 140 2.146 1150 3.061 173 2.238 14 1.146 1094 3.039 1068 3.029 775 2.889 1202 3.080

229


B I G R A M POSITION 3RD 2ND 1ST

FL FO FR FS FT FU FW FY GA GD

GE GG

GR

GS GT

19 1.279 137 2.137 0 0.000 0 0.000 55 1.740

72 1.857 0 0.000 0 0.000 0 0.000 8 .903 188 2.274 0 0.000

0 0.000 0 0.000 0 0.000 23 1.362 0 0.000 0 0.000 0 0.000

326 2.513 966 2.985 459 2.662 23 1.362 139 2.143 623 2.794 18 1.255

89 1.949 21 1.322 0 0.000 927 2.967 0 0.000

89 1.949

974 2.989 0 0.000 0 0.000 0 0.000 158 2.199 106 2.025 0 0.000 102 2.009 0 0.000

2269 3.356 511 2.708 534 2.728 19 1.279 308 2.489 135 2.130 1218 3.086 106 2.025 34 1.531

0 0.000 0 0.000 318 2.502 0 0.000

0 0.000 0 0.000 0 0.000 0 0.000

0 0.000 76 1.881 98 1.991 0 0.000

0 0.000 157 2.196 0 0.000 910 2.959 0 0.000

0 0.000

0 0.000 107 2.029 0 0.000 89 1.949 144 2.158

0 0.000 47 1.672 26 1.415 429 2.632 1.633

0 0.000 18 1.255 0 0.000 7 68 2.885 0 0.000

221 2.344

161 2.207

9 07 2.958

120 2.079 361 2.558 19 1.279 71 1.851 0 0.000 94 1.973 0 0.000 0 0.000

327 2.515 56 1.748 0 0.000 0 0.000 4 .602 416 2.619 0 0.000 34 1.531

46 1.663 0 0.000 0 0.000 41 1.613 0 0.000 0 11.000 4 .602 0 0.000

15 1.176 117 2.068 0 0.000 4 .602 25 1.398 708 2.850 0 0.000 0 0.000

GO

SUM

2.207 10 1.000

GI

GN

6TH

0 0.000 0 0.000 28 1.447

6 .778

GM

5TH

206 2.314 668 2.825 421 2.624

GH

GL

4TH

626 2.797 0 0.000 0 0.000 0 0.000 0 0.000 3 .477 0 0.000 0 0.000 34 1.531 0 0.000 0 0.000 0 0.000 0 0.000

29 1.462

161

19 1.279 18 1.255

43

976 2.989 25 1.415 3123 3.495 187 2.272

CHAPTER 5

230

BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7 BIGRAM POSITION 1ST 2ND 3RD GU

GY HA HE

HF HI HL

HM HN HO

HR HS HT

HU HW HY IA

IB IC

ID IE

4TH

5TH

6TH

SUM

267 2.421 0 0.000 67 1.826 19 1.279 0 0.000 148 2.170 9 .954 0 0.000 34 1.531 217 2.336 0 0.000 0 0.000

21 1.322 0 0.000 397 2.599 155 2.190 9 .954 731 2.864 0 0.000 0 0.000 0 0.000 794 2.900 0 0.000 0 0.000

19 1.279 0 0.000 32 1.505 2568 3.410 0 0.000 56 1.748 58 1.763 12 1.079

0 0.000 35 1.544 0 0.000 32 1.505 0 0.000 0 0.000 0 0.000 0 0.000

347 2.540 35 1.544 1807 3.257 4060 3.609 9 .954 2353 3.372 67 1.826 12 1.079

0 0.000 863 2.936 0 0.000 0 0.000

0 0.000 0 0.000 884 2.946 781 2.893 0 0.000 385 2.585 0 0.000 0 0.000 0 0.000 761 2.881 1053 3.022 0 0.000

0 0.000 85 1.929 0 0.000 0 0.000

0 0.000 0 0.000 0 0.000 26 1.415

34 1.531 2720 3.435 1053 3.022 26 1.415

0 0.000 401 2.603 0 0.000 3 .477 0 0.000 0 0.000 0 0.000 17 1.230 0 0.000

0 0.000 27 1.431 0 0.000 72 1.857 55 1.740 203 2.307 526 2.721 57 1.756 41 1.613

0 0.000 7 .845 0 0.000 0 0.000 0 0.000 40 1.602 288 2.459 108 2.033 446 2.649

117 2.068 0 0.000 40 1.602 0 0.000 79 1.898 85 1.929 888 2.948 432 2.635 853 2.931

60 1.778 3 .477 0 0.000 0 0.000 719 2.857 0 0.000 794 2.900 498 2.697 1323 3.122

907 2.958 0 0.000 0 0.000 70 1.845 76 1.881 0 0.000 350 2.544 49 1.690 69 1.839

1084 3.035

40 1.602 0 0.000 427 2.630 505 2.703 0 0.000 1033 3.014 0 0.000 0 0.000

4 38 2.641 40 1.602 145 2.161 929 2.968 328 2.516 2846 3.454 1161 3.065 2732 3.436

APPENDIX 5.2

231


IF IG IK IL

IM

IN I0

IP IQ IR

IS IT

IU IV

IX I2 JA JE JO

JU KA

1ST

2ND

3RD

4TH

5TH

6TH

SUM

0 0.000 34 1.531 0 0.000 32 1.505 249 2.396 825 2.916 0 0.000 0 0.000

90 1.954 489 2.689 3 .477 791 2.898 899 2.954 1068 3.029 67 1.826 16 1.204

126 2.100 98 1.991 0 0.000 429 2.632 280 2.447 538 2.731 24 1.380 100 2.000

38 1.580 195 2.290 20 1.301 201 2.303 252 2.401 941 2.974 933 2.970 10 1.000

0 0.000 0 0.000 7 .845 126 2.100 19 1.279 582 2.834 6 .778 39 1.591

347 2.540 977 2.990 49 1.690 1972 3.295 1751 3.243 11841 4.073 2381 3.377 169 2.228

0 0.000 18 1.255 42 1.623 51 1.708

6 .778 162 2.210 927 2.967 957 2.981 0 0.000 117 2.068 75 1.875 22 1.342 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

0 0.000 80 1.903 192 2.283 976 2.989

12 1.079 166 2.220 220 2.342 419 2.622

93 1.968 161 2.207 19 1.279 393 2.594 52 1.716 7787 3.891 1351 3.131 4 .602 0 0.000 264 2.422 704 2.848 636 2.803

0 0.000 21 1.322 47 1.672 235 2.371

18 1.255 711 2.852 2132 3.329 3274 3.515

22 1.342 291 2.464 0 0.000 15 1.176 3 .477 76 1.881 62 1.792 26 1.415 4 .602

0 0.000 216 2.334 14 1.146 57 1.756 0 0.000 2 54 2.405 0 0.000

48 1.681 190 2.279 0 0.000 79 1.898 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

0 0.000 0 0.000 9 .954 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

70 1.845 8 14 2.911 98 1.991 173 2.238 114 2.057 349 2.543 192 2.283 237 2.375 45 1.653

0 0.000 0 0.000 0 0.000 0 0.000 111 2.045 19 1.279 130 2.114 211 2.324 21 1.322

0

0.000 20 1.301

CHAPTER 5

232


BIGRAM POSITION 1ST 2ND 3RD

KE KI KL KM KN KO

KP KR

KS KU

KW KY

213 2.328 183 2.262 0 0.000 0 0.000 104 2.017 0 0.000 0 0.000 11 1.041 0 0.000 0 0.000 0 0.000 0 0.000

LA

312 2.494

LB

0 0.000 0 0.000 0 0.000 706 2.849

LC LD

LE LF LG

LH LI

0 0.000 0 0.000 0 0.000 497 2.696

4TH

5TH

6TH

SUM

3 94 2.595 0 0.000 127 2.104 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

56 1.748 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

94 2 2.974 1128 3.052 130 2.114 7 .845 151 2.179 15 1.176 16 1.204

0 0.000

11 1.041

81

120 2.079 3 .477 17 1.230 5 .699 2592 3.414

0 0.000 43 1.633 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

3 .477 4 .602 0 0.000 0 0.000 47 1.672 0 0.000 0 0.000 0 0.000

276 2.441 898 2.953 3 .477 7 .a45 0 0.000 15 1.176 16 1.204 0 0.000

0 0.000 0 0.000 0 0.000 5 .699 890 2.949

0 0.000 0 0.000 11 1.041 0 0.000

39 1.591 0 0.000 6 .778 0 0.000

0 0.000 3 .477 0 0.000 0 0.000

341 2.533

525 2.720

465 2.667

1.908 0 0.000 0 0.000 0 0.000 59 1.771

0 0.000 13 1.114 13 1.114 429 2.632 0 0.000 0 0.000 0 0.000 219 2.340

3 .477 73 1.863 135 2.130 226 2.354 88 1.944 21 1.322 14 1.146 378 2.577

0 0.000 0 0.000 71 1.851 661 2.820 5 .699 0 0.000 0 0.000 2380 3.377

0 0.000 0 0.000 0 0.000 1478 3.170 0 0.000 9 .954 0 0.000 73 1.863

0.000 0 0.000 18 1.255 993 2.997 733 2.865 0 0.000 0 0.000 9 .954

0

3 .477 86 1.934 2 37 2.375 4493 3.653 826 2.917 30 1.477 14 1.146 3556 3.551

APPENDIX 5 . 2

233

B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 7 B I G R A M POSITION 1ST 2ND 3RD

LK LL LM LN LO

LP LR

LS LT LU LV LW

0 0.000 0 0.000 0 0.000 0 0.000 429 2.632 0 0.000 0 0.000 0 0.000 0 0.000 39 1.591 0 0.000 0 0.000

LY

7 .845

MA

901 2.955 0 0.000 1222 3.087 0 0.000

MB

ME

MF MI ML MM MN

833 2.921 0 0.000 0 0.000 0 0.000

0 0.000 133 2.124 0 0.000 0 0.000 425 2.628 0 0.000 273 2.436 0 0.000 22 1.342 87 1.940 4 .602 0 0.000 16 1.204 213 2.328 30 1.477 273 2.436 0 0.000 78 1.892 0 0.000 19 1.279 0 0.000

154 2.188 1528 3.184 4 -602 25 1.398 225 2.352 76 1.881 0 0.000 13 1.114 107 2.029 92 1.964 13 1.114 5 .699 5 .699 235 2.371 561 2.749 251 2.400 43 1.633 306 2.486 5 .699 177 2.248 0 0.000

4TH

5TH

6TH

SUM

7 .845 209 2.320

0 0.000 569 2.755 0 0.000 0 0.000 113 2.053 0 0.000 35 1.544 253 1.301

0 0.000 110 2.041 7 .845 47 1.672 16 1.204 0 0.000 0 0.000 484 2.685

161 2.207 2549 3.406

292 2.465 27 1.431 44 1.643 0 0.000 0 0.000 162 2.210 7 .845 442 2.645 0 0.000

33 1.519 0 0.000 0 0.000 0 0.000 1924 3.284 58 1.763 0 0.000 246 2.391 0 0.000

35 1.544 0 0.000 25 1.398 36 1.556

0 0.000 0 0.000 0 0.000 13 1.114

0 0.000 0 0.000 288 2.459 0 0.000 0 0.000 0 0.000 133 2.124 214 2.330 16 1.204 19 1.279 17 1.230 440 2.643 114 2.057 241 2.382 4 .602 297 2.473 11

1.041 38 1.580 7 .845

11 1.041 72 1.857 1496 3.175 76 1.881 308 2.489 517 2.713 587 2.769 4 59 2.662 77 1.886 24 1.380 1969 3.294 2009 3.303 712 2.852 2675 3.427 47 1.672 1549 3.190 16 1.204 2 59 2.413 56 1.748

234

CHAPTER 5


B I G R A M POSITION

1ST

2ND

3RD

4TH

5TH

6TH

SUM

471 2,673 0 0.000 0 0.000 0 0.000 180 2.255 42 1.623 358 2.554 0 0.000 0 0.000 0 0.000 394 2.595 0 0.000

90 1.954 197 2.294 0 0.000 0 0.000 17 1.230 0 0.000 131 2.117 3 .477 195 2.290 127 2.104 38 1.580 36 1.556

136 2.134 602 2.780 4 .602 603 2.780 0 0.000 0 0.000 476 2.678 0 0.000 448 2.651 596 2.775 718 2.856 55 1.740

0 0.000 117 2.068 0 0.000 0 0.000 159 2.201 0 0.000 92 1.964 0 0.000

0 0.000 0 0.000 0 0.000 227 2.356 0 0.000 112 2.049 38 1.580 0 0.000

842 2.925 1264 3.102 4 .602 838 2.923 433 2.636 154 2.188 1176 3.070 16 1.204

509 2.707 450 2.653 638 2.805 0 0.000

NG

0 0.000

NH

0 0.000 3 .477 0 0.000 0 0.000 0 0.000

498 2.697 50 1.699 220 2.342 77 1.886 47 1.672 7 .845 9 .954 15 1.176 782 2.893

3 29 2.517 6 .778 193 2.286 0 0.000 115 2.061 3 .477

145 2.161 348 2.542 0 0.000 8 .903 77 1.886 0 0.000 81 1.908 13 1.114 228 2.358 244 2.387 4 24 2.627 25 1.398 309 2.490 0 0.000 1231 3.090 0 0.000 73 1.863 35 1.544

230 2.362 0 0.000 87 1.940 0 0.000 0 0.000 21 1.322

0 0.000 530 2.724 502 2.701 0 0.000 7212 3.858 0 0.000 9 .954 0 0.000 0 0.000 0 0.000

1380 3.140 1947 3.289 2714 3.434 116 2.064 8578 3.933 56 1.748 1743 3.241 77 1.886 235 2.371 66 1.820

4 .602 373 2.572 150 2.176

0 0.000 149 2.173 142 2.152

0 0.000 32 1.505 10 1.000

0 0.000 0 0.000 10 1.000

13 1.114 559 2.755 1679 3.225

MO

MP MR MS MU

MY NA NB NC ND NE

NF

NI

NJ NK

NL

NM NN

NO

0 0.000 0 0.000 585 2.767

235

APPENDIX 5 . 2 B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 7 B I G R A M POSITION 3 RD 1ST 2ND

NQ NR

NS NT NU NV

NX

NY NZ OA

OB

oc OD

OE

OF OG OH 01

OJ OK

OL

0 0.000 0 0.000 0 0.000 0 0.000 288 2.459 0 0.000 0 0.000 0 0.000

28 1.447 3 .477 3 57 2.553 242 2.384 69 1.839 88 1.944 71 1.851 46 1.663

0 0.000 0 0.000 229 2.360 51 1.708 0 0.000 0 0.000 237 2.375 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 7 .845

11 1.041 130 2.114 87 1.940 460 2.663 43 1.633 0 0.000 0 0.000 39 1.591 34 1.531 115 2.061 5 .699 0 0.000 888 2.948

10 1.000 10 1.000 2 38 2.377 1110 3.045 293 2.467 29 1.462 0 0.000 10 1.000 0 0.000 47 1.672 318 2.502 295 2.470 185 2.267 22 1.342 48 1.681 399 2.601 0 0.000 37 1.568 93 1.968 230 2.362 162 2.210

4TH

5TH

6T9

SUM

0 0.000 0 0.000 89 1.949 732 2.865 10 1.000 0 0.000 0 0.000 0 0.000 0 0.000 12 1.079 51 1.708 5 .699 14 1.146 0 0.000 7 .845

0 0.000 6 .778 946 2.976 332 2.521 42 1.623 0 0.000 0 0.000 3 .477 3 .477 0 0.000 0 0.000 8 .903 249 2.396 58 1.763 0 0.00a 29 1.462 0 0.000 80 1.903 0 0.000 3 .477 329 2.517

0 0.000 0 0.000 1197 3.078 1653 3.218 0 0.000 0 0.000 5 .699 467 2.669 0 0.000 0 0.000 0 0.000 0 0.000 25 1.398 0 0.000 16 1.204 0 0.000 0 0.000 0 0.000 0 0.000 36 1.556 264 2.422

38 1.580 19 1.279 2827 3.451 4069 3.609 702 2.846 117 2.068 76 1.881 526 2.721 14 1.146 189 2.276 685 2.836 819 2.913 516 2.713 80 1.903 308 2.489 476 2.678 47 1.672 2 59 2.413 98 1 991 293 2 467 720 3 236

9 .954 13 1.114 27 1.431 0 0.000 24 1.380 70 1.845

2 36

CHAPTER 5

BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7 BIGRAM POSITION 1ST 2ND 3RD OM

ON

00

OP

OQ OR 0s

OT

ou

ov

ow

ox OY PA PD PE PF PG PH PI PK

25 1.398 5 .699 0 0.000 331 2.520 0 0.000 200 2.301 0 0.000 0 0.000

942 2.974 1044 3.019 356 2.551 140 2.146 0 0.000 1337 3.126 99 1.996 704 2.848

343 2.535 24 1.380

1348 3.130 164 2.215 681 2.833 0 0.000 51 1.708 59 1.771 3 .477 508 2.706 0 0.000 3 .477 4 .602 160 2.204 0 0.000

0 0.000 0 0.000 8 .903 949 2.977 0 0.000 810 2.908 0 0.000 0 0.000 57 1.756 317 2.501 0 0.000

133 2.124 143 2.155 55 1.740 379 2.579 0 0.000 274 2.438 187 2,272 1023 3.010 1108 3.045 238 2.377 413 2.616 0 0.000 3 .477 79 1.898 0 0.000 3 79 2.579 0 0.000 0 0.000 3 .477 265 2.423 7 .845

4TH

5TH

6TH

SUM

125 2.097 150 2.176 208 2.318 21 1.322 11 1.041 526 2.721 115 2.061 82 1.914

194 2.288 92 5 2.966 153 2.185 6 .778 0 0.000 1105 3.043 278 2.444 57 1.756

229 2.360 1664 3.221 0 0.000 89 1.949 0 0.000 195 2.290 0 0.000 13 1.114

1648 3.217 3931 3.595 772 2.888 966 2.985 11 1.041 3637 3.561 679 2.832 1879 3.274

1101 3.042 2 29 2.360 98 1.991 0 0.000 64 1.806 4 03 2.605 0 0.000 263 2.420 29 1.462 0 0.000 40 1.602 382 2.582 0 0.000

1261 3.101 53 1.724 245 2.389 0 0.000 13 1.114 0 0.000 0 0.000 571 2.757 0 0.000 0 0.000 0 0.000 23 1.362 0 0.000

0 0.000 0 0.000 112 2.049 9 .954 48 1.681 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 22 1.342 0 0.000

5161 3.713 708 2.850 1549 3.190

0 0.000

9 .954 187 2.272 1490 3.173 3 .477 2531 3.403 29 1.462 3 .477 126 2.100 1147 3.060 7 .845

237

APPENDIX 5 . 2 BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7 B I G R A M POSITION 1ST 3RD 2N D

PL PM PO PP PR PS PT PU PW PY QU

RA RB

RC

RD RE

RF RG

RH RI

RK

468 2.670 0 0.000 412 2.615 0 0.000 2730 3.436 3 .477 0 0.000 321 2.507 0 0.000 0 0.000 358 2.554 311 2.493 0 0.000 0 0.000 0 0.000 2781 3.444 0 0.000 0 0.000 12 1.079 118 2.072 0 0.000

0 0.000 0 0.000 51 1.708 294 2.468 51 1.708 3 .477 G3 1.799 6 .778 6 .778 0 0.000 113 2.053 774 2.889 5 .699 8 .903 93 1.968 1463 3.165 0 0.000 63 1.799 0 0.000 1457 3.163 0 0.000

361 2.558 0 0.000 223 2.348 397 2.599 166 2.220 5 .699 141 2.149 128 2.107 0 0.000 0 0.000 199 2.299 280 2.447 50 1.699 173 2.238 102 2.009 870 2.940 340 2.531 212 2.326 307 2.487 858 2.933 350 2.544

4TH

5TH

6TH

SUM

289 2.461 6 .77 8 585 2.767 437 2.640 0 0.000 15 1.176 160 2.204 46 1.663 0 0.000 0 0.000 26 1.415 456 2.659 8 .903 99 1.996 37 1.568 661 2.820 13 1.114 183 2.262 0 0.000 12c15 3.081 7 .845

3 49 2.543 0 0.000 0 0.000 26 1.415 0 0.000 19 1.279 6 .778 0 0.000 0 0.000 0 0.000 23 1.362 2059 3.314 18 1.255 41 1.613 190 2.279 1219 3.086 0 0.000 18 1.255 0 0.000 74 1.869 53 1.724

0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 313 2.496 203 2.307 0 0.000 0 0.000 38 1.580 0 0.000 32 1.505 15 1.176 0 0.000 317 2.501 1087 3.036 0 0.000 0 0.000 0 0.000 0 0.000 39 1.591

1467 3.166 6 .778 1271 3.104 1154 3.062 2947 3.469 358 2.554 573 2.758 501 2.700 6 .778 38 1.580 719 2.857 3912 3.592 96 1.982 321 2.507 739 2.869 8081 3.907 353 2.548 476 2.678 319 2.504 3712 3.570 449 2.652

238

CHAPTER 5


1ST RL RM RN RO

RP RQ RR

RS RT RU

RV RW RY SA

SB

sc SD

0 0.000 0 0.000 0 0.000 247 2.393 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 257 2.410 0 0.000 0 0.000 0 0.000 163 2.212 0 0.000 454 2.657 0 0.000

SE

1655 3.219

SF

0 0.000 554 2.744 569 2.755

SH

SI

2ND 40 1.602 3 .477 0 0.000 2640 3.422 0 0.000 0 0.000 111 2.045 3 .477 123 2.090 182 2.260 0 0.000 0 0.000 26 1.415 0 0.000 0 0.000 22 1.342 0 0.000 17 1.230 0 0.000 23 1.362 0 0.000

3RD

4TH

5TH

6TH

SUM

199 2.299 372 2.571 494 2.694 1047 3.020 207 2.316 4 .602 630 2.799 4 59 2.662 842 2.925 5 .699 502 2.701 142 2.152

183 2.262 90 1.954 222 2.345 289 2.461 41 1.513 0 0.000 52 1.716 86 1.934 373 2.572 23 1.362 3 .477 15 1.176

219 2.340 20 1.301 45 1.653 302 2.480 6 .778 0 0.000 7 .845 53 1.724 388 2.589 5 .699 74 1.869 0 0.000

0 0.000 109 2.037 4 50 2.653 4 .602 0 0.000 0 0.000 0 0.000 2299 3.362

641 2.807 594 2.774 1211 3.083 4529 3.656 254 2.405 4 .602 800 2.903 2900 3.462 2082 3.318 472 2.674 579 2.763 157 2.196

42 1.623

0 0.000 128 2.107 0 0.000 0 0.000 59 1.771 1283 3.108 0 0.000 189 2.276 1154 3.062

0 0.000

1485 3.172 5 .699 0 0.000 0 0.000 0 0.000 1832 3.263 0 0.000 455 2.658 0 0.000

15 1.176 131 2.117 104 2.017 3 .477 241 2.382 0 0.000 204 2.310 416 2.619

18 1.255 0 0.000 0 0.000 0 0.000 777 2.890 16 1.204 0 0.000 58 1.833

3 56 2.551 0 0.000 0 0.000 0 0.000

1553 3.191 329 2.517 131 2.117 580 2.763 62 1.792 5805 3.764 16 1.204 1425 3.154 2207 3.344

APPENDIX 5.2

239

B I G R A M FREQUENCIES F O R WORDS OF LETTER LENGTH 7 B I G R A M POSITION

1ST

2ND

3RD

4TH

5TH

6TH

SUM

48 1.681 186 2.270 160 2.204 56 1.748 665 2.823 586 2.768 29 1.462

0 0.000 30 1.477 0 0.000 0 0.000 8 .903 70 1.845 3 .477

3 .477 14 1.146 5 .699 0 0.000 29 1.462 415 2.618 0 0.000

79 1.898 234 2.369 199 2.299 56 1.748 1179 3.072 1100 3.041 32 1.505

0 0.000 168 2.225 8 .903 206 2.314 0 0.000

5 .699

0 0.000 4 .602 0 0.000 0 0.000 170 2.230 0 0.000 0 0.000 0 0.000

6 .778 0 0.000 30 1.477 0 0.000 17 1.230 0 0.000 0 0.000

0 0.000 0 0.000 1586 3.200 1124 3.051 84 1.924

22 1.342 0 0.000 4 .602 0 0.000 290 2.462 2Y 1.462 0 0.000 0 0.000

0 0.000

.699

6 66 2.823 1550 3.190 317 2.501 44 1.643

326 2.513 338 2.529 2 33 2.367 0 0.000

31 1.491 140 2.146 0 0.000 0 0.000

644 2.809 1204 3.081 0 0.000 0 0.000

1835 3.264 4826 3.684 1880 3.274 128 2.107

SY

173 2.238

3 .477

203 2.307 0 0.000 0 0.000 0 0.000 374 2.573 0 0.000 0 0.000 1813 3.258

584 2.766 0 0.000 4 .602 0 0.000 161 2.207 0 0.000 0 0.000 38 1.580

0 0.000 826 2.917 0 0.000 0 0.000 0 0.000

0 0.000 167 2.223 0 0.000 35 1.544 0 0.000 2777 3.444 0 0.000 0 0.000 96 1.982

40 1.602

TA

0 0.000 214 2.330 3 .477 312 2.494 27 1.431 426 2.629 3 .477 4 .602 1242 3.094

216 2.334 2029 3.307 3 .477 351 2.545 27 1.431 5745 3.759 6 .I78 12 1.079 4979 3.697

SK

SL SM

SN SO

SP

SQ SR SS

ST SU

sw

TB TC TD TE TF TG TH

1412 3.150 3 .477 8 .903 1675 3.224

35 1.544 0 0.000 0 0.000 0 0.000 595 2.775 0 0.000 0 0.000 115 2.061

5

CHAPTER 5

240


B I G R A M POSITION

6TH

SUM

2558 3.408 108 2.033 46 1.663 633 2.801 0 0.000 484 2.685 0 0.000 244 2.387 747 2.873 11 1.041 0 0.000 57 1.756

97 1.987 378 2.577 0 0.000 246 2.391 0 0.000 390 2.591 0 0.000 19 1.279 10 1.000 0 0.000 0 0.000 102 2.009

0 0.000 0 0.000 0 0.000 17 1.230 0 0.000 0 0.000 1678 3.225 16 1.204 0 0.000 0 0.000 1010 3.004 0 0.000

3558 3.551 578 2.762 82 1.914 1540 3.188 8 .903 2021 3.306 1895 3.278 1463 3.165 1483 3.171 812 2.910 1089 3.037 6 57 2.818

29 1.462 112 2.049 3 37 2.528 42 1.623 8 .903 127 2.104

142 2.152 105 2.021 15 1.176 71 1.851 0 0.000 783 2.894

0 0.000 224 2.350 134 2.127 107 2.029 0 0.000 974 2.989

4 .602 0 0.000 5 .699 -77 1.886 0 0.000 0 0.000

408 2.611 710 2.851 535 2.728 380 2.580 48 1.681 1955 3.291

19 1.279 0 0.000 28 1.447

214 2.330 0 0.000 490 2.690

57 1.756 0 0.000 95 1.978

0 0.000 0 0.000 188 2.274

507 2.705 4 .602 939 2.973

2N D

3RD

62 1.792 0 0.000 0 0.000 283 2.452 0 0.000 693 2.841 7 .845 0 0.000 192 2.283 28 1.447 76 1.881 0 0.000

68 1.833 35 1.544 0 0.000 297 2.473 0 0.000 278 2.444 0 0.000 177 2.248

773 2.888 57 1.756 36 1.556 64 1.806 8 .903 176 2.246 210 2.322 1007 3.003 203 2.307 773 2.888 0 0.000 294 2.468

UB

0 0.000

'JC

0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

233 2.367 269 2.430 44 1.643 83 1.919 40 1.602 71 1.851 217 2.336 4 .602 138 2.140

TI TL TN TO TP TR TS TT TU TW TY UA

OD UE UF UG

UI UK

UL

0 0.000 0 0.000 0 0.000

331 2.520 0 0.000 3 .477 204 2.310

4TH

5TH

1ST

241

APPENDIX 5 . 2 B I G R A M FREQUENCIES FOR WORDS OF LETTER LENGTH 7 B I G R A M POSITION 1ST 2ND 3 RD UM UN

uo UP UR

US UT

0 0.000 247 2.393 0 0.000 29 1.462 12 1.079 223 2.348 92 1.964

UZ

0 0.000

VA

374 2.573 196 2.292 409 2.612

VE VI

vo

vu WA

WB WD WE

WF WH WI WK

60 1.778 4 .602 498 2.697 0 0.000 0 0.000 559 2.747 0 0.000 446 2.649 1018 3.008 0 0.000

216 2.334 481 2.682 3 .477 337 2.528 1185 3.074 631 2.800 508 2.706 29 1.462 5 .699 298 2.474 56 1.748 27 1.431 0 0.000 44 1.643 0 0.000 0 0.000 32 1.505 10 1.000 0 0.000 43 1.633 11 1.041

29 1.462 812 2.910 0 0.000 34 1.531 313 2.496 291 2.464 98 1.991 0 0.000 130 2.114 790 2.898 358 2.554 143 2.155 0 0.000 77 1.886 10 1.000 11 1.041 576 2.760 0 0.000 29 1.462 0 0.000 0 0.000

4TH

5TH

6TH

SUM

212 2.326 120 2.079 10 1.000 5 .699 444 2.647 156 2.193 258 2.412 0 0.000 278 2.444 245 2.389 892 2.950 27 1.431 0 0.000 169 2.228 0 0.000 32 1.505 867 2.938 0 0.000 0 0.000 377 2.576 0 0.000

30 1.477 162 2.210 0 0.000 13 1.114 936 2.971 933 2.970 95 1.978

207 2.316 23 1.362 0 0.000 6 .778 39 1.591 664 2.822 627 2.797 0 0.000 0 0.000 629 2.799 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

694 2.841 1845 3.266 13 1.114 4 24 2.627 2929 3.467 2898 3.462 1678 3.225 29 1.462 867 2.938 3184 3.503 1715 3.234 257 2.410 4 .602 924 2.966 10 1.000 43 1.633 2163 3.335 10 1.000 475 2.677 1438 3.158 11 1.041

0 0.000 80 1.903 1026 3.011 0 0.000 0 0.000 0 0.000 136 2.134 0 0.000 0 0.000 129 2.111 0 0.000 0 0.000 0 0.000 0 0.000

242

CHAPTER 5

BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7 B I G R A M POSITION 2ND 1ST 3RD

WL WM

0 0.000 0 0.000

WN

0 0.000

WO

389 2.590 0 0.000 370 2.568 0 0.000 9 .954 0 0.000

WP WR

ws WY XA

xc XE XH XI

XP XT

xw YA YB YC

YE YF

0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 28 1.447 0 0.000 0 0.000 9 .954 0 0.000

4TH

5TH

6TH

SUM

0 0.000 0 0.000 0 0.000 21 1.322 0 0.000 0 0.000 0 0.000 0 0.000

3 .477 0 0.000 0 0.000 0 0.000 27 1.431 4 .602 4 .602 23 1.362

31 1.491 3 .477 21 1.322 44 1.643 0 0.000 0 0.000 0 0.000 0 0.000

0 0.000 0 0.000 4 .602 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

0 0.000 0 0.000 56 1.748 0 0.000 0 0.000 0 0.000 198 2.297 0 0.000

34 1.531 3 .477 81 1.908 4 54 2.657 27 1.431 374 2.573 202 2.305 32 1.505

435 2.638 49 1.690 20 1.301 32 1.505 40 1.602 298 2.474 80 1.903 0 0.000 0 0.000 0 0.000 0 0.000 11 1.041 0 0.000

8 .903 0 0.000 0 0.00(1 0 0.000 177 2.248 0 0.000 118 2.072 11 1.041 32 1.505 81 1.908 11 1.041 4 .602 0 0.000

0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

0 0.000 0 0.000 31 1.491 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 38 1.580 0 0.000 0 0.000 0 0.000

5 .699 64 1.806 3 .477

0 0.000 99 1.996 0 0.000

0 0.000 6 .778 0 0.000

443 2.646 49 1.690 51 1.708 32 1.505 217 2.336 298 2.474 2 36 2.373 11 1.041 60 1.778 81 1.908 16 1.204 193 2.286 3 .477

243

APPENDIX 5 . 2 BIGRAM FREQUENCIES FOR WORDS OF LETTER LENGTH 7

YG YH YI

YL YM YN YO

YP YR

YS YT YW YZ

ZA

ZE Z I

ZL

zo

zu ZY

zz

B I G R A M POSITION 3RD 2ND 1ST

4TH

5TH

6TH

SUM

0 0.000 8 .903 0 0.000 12 1.079 81 1.908 13 1.114 0 0.000 3 .477 54 1.732 45 1.653 31 1.491 17 1.230 0 0.000 32 1.505 10 1.000 0 0.000 0 0.000 0 0.000 0 0.000 11 1.041 29 1.462

0 0.000 0 0.000 194 2.288 0 0.000 11 1.041 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 27 1.431 0 0.000 0 0.000 0 0.000 0 0.000 39 1.591 23 1.362 9 -954 6 .I78 0 0.000 0 0.000

0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 7 .845 0 0.000 0 0.000 10 1.000 0 0.000 33 1.519 0 0.000 0 0.000 27 1.431 0 0.000 0 0.000 0 0.000

0 0.000 0 0.000 0 0.000 0 0.000 3 .477 0 0.000 0 0.000 0 0.000 0 0.000 57 1.756 0 0.000 0 0.000 0 0.000 3 .477 100 2.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

3 .477 8 .903 206 2.314 12 1.079 136 2.134 46 1.663 53 1.724 75 1.875 72 1.857 288 2.459 58 1.763 17 1.230 10 1.000 35 1.544 150 2.176 39 1.591 23 1.362 36 1.556 6 .I18 11 1.041 29 1.462

0 0.000 0 0.000 12 1.079 0 0.000 0 0.000 0 0.000 44 1.643 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 7 .84 5 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000

3 .417 0 0.000 0 0.000 0 0.000 41 1.613 33 1.519 9 .954 72 1.857 18 1.255 179 2.253 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.000 0 0.Q00 0 0.000


6

Summary and Conclusion

T h e g o a l o f t h i s r e s e a r c h p r o j e c t was t o e v a l u a t e how t h e reader's higher-order knowledge a b o u t o r t h o g r a p h i c s t r u c t u r e i n t e r a c t s with f e a t u r a l information during t h e processing of l e t t e r s a n d w o r d s . The r e s e a r c h was c a r r i e d o u t u t i l i z i n g a g e n e r a l i n f o r m a t i o n p r o c e s s i n g model , which provided a formal framework from which hypotheses could be d e r i v e d and tested. The model a l o n g w i t h s u p p o r t i n g e v i d e n c e was d e s c r i b e d i n C h a p t e r 1. S i n c e t h e s t u d y o f v i s u a l p r o c e s s i n g i n r e a d i n g requires a n examination of t h e v i s u a l f e a t u r e s t h a t a r e functional during reading, t h e discussion i n Chapter 2 described those features u t i l i z e d i n t h e r e c o g n i t i o n of lowercase l e t t e r s . Understanding f e a t u r e d e t e c t i o n proved u s e f u l i n a c c o u n t i n g f o r some o f t h e f i n d i n g s i n t h e p e r c e p t u a l The s i g n i f i c a n t recognition tasks described i n Chapter 4. f i n d i n g w a s t h a t t h e s e a r c h f o r a t a r g e t l e t t e r was c r i t i c a l l y dependent o n t h e f e a t u r a l s i m i l a r i t y between t h e t a r g e t l e t t e r and t h e l e t t e r s i n t h e t e s t s t r i n g . The f u n d a m e n t a l p r o p e r t i e s o f t h e o r t h o g r a p h i c s t r u c t u r e of E n g l i s h w e r e d e s c r i b e d i n C h a p t e r 3. We d i s t i n g u i s h e d two b r o a d c a t e g o r i e s o f d e s c r i p t i o n s . T h e f i r s t was d e r i v e d f r o m s t a t i s t i c a l - r e d u n d a n c y measures based on t h e frequency with l e t t e r s e q u e n c e s , and words o c c u r i n natural which l e t t e r s , texts. The s e c o n d c a t e g o r y , r u l e - g o v e r n e d r e g u l a r i t y , was based on p h o n o l o g i c a l c o n s t r a i n t s o f E n g l i s h and s c r i b a l conventions governing t h e s p e l l i n g of English. Also included i n Chapter 3 was a b r i e f r e v i e w o f p r e v i o u s s t u d i e s o f orthography I n Chapter 4 , w e examined t h e p s y c h o l o g i c a l r e a l i t y o f various descriptions of orthographic s t r u c t u r e in perceptual r e c o g n i t i o n t a s k s and o v e r t judgment t a s k s . The r e c o g n i t i o n

.

246

CHAPTER 6

t a s k s a s s e s s e d t h e d e g r e e t o w h i c h k n o w l ed g e o f o r t h o g r a p h i c i n word p e r c e p t i o n , and t h e o v e r t s t r u c t u r e is u t i l i z e d j u d g m e n t t a s k s a s s e s s e d t h e d e g r e e - t o w h i c h t h i s k n o w l e d g e is consciously available. G i v e n o u r p r e v i o u s r e s u l t s ( M a s s a r o e t a l . , 1 9 7 9 ) , we had r e a s o n t o s u s p e c t d i f f e r e n c e s b e t w e e n r e a c t i o n time t a s k s an d of their sensitivities to the a c c u r a c y t a s k s i n terms u t i l i z a t i o n o f o r t h o g r a p h i c s t r u c t u r e . We b e g a n w i t h a d i r e c t c o m p a r i s o n b e t w e e n t h e s e two tasks, while simultaneously c o n t r a s t i n g a ru le-g o v ern ed meas u re and a s t a t i s t i c a l - r e d u n d a n cy measure o f o r t h o g r a p h i c s t r u c t u r e . Rep1 i c a t i n g o u r p r e v i o u s wo r k , w e f o u n d h i g h l y s i g n i f i c a n t e f f e c t s o f o r t h o g r a p h i c s t r u c t u r e i n t h e a c c u r a c y t a s k and r e l a t i v e l y s m a l l , and sometimes n o n s i g n i f i c a n t , effects in the r e a c t i o n time task. The n e x t s i x e x p e r i m e n t s a s s e s s e d w h a t a s p e c t s o f t h e two t a s k s a c c o u n t e d f o r t h e d i f f e r e n c e s t h a t were o b s e r v e d . We evaluated t h e influences of presenting t h e t a r g e t letter before o r a f t e r t h e test d i s p l a y , t h e c o n t r i b u t i o n of a f e a t u r e d e t e c t i o n s t r a t e g y , t h e r o l e of limited stimulus information, and t h e s e n s i t i v i t y o f s p e e d e d r e a c t i o n - t i m e e x p e r i m e n t s . The reason t h a t t h e magnitude of t h e e f f e c t a p p e a r s s m a l l e r f o r a h i g h a c c u r a c y r e a c t i o n - t i m e m e a s u r e is t h a t t h e d i f f e r e n c e s i n v i s u a l p r o c e s s i n g time a r e s m a l l r e l a t i v e t o t h e o v e r a l l In contrast, the stimulus r e a c t i o n time t o c o m p l e t e t h e t a s k . parameters a r e modified i n t h e accuracy t a s k t o keep average performance a t 75% c o r r e c t ; any d i f f e r e n c e s i n accuracy a r e then i n f l u e n c e d a l m o s t c o m p l e t e l y by v i s u a l processing. Supporting this interpretation, t h e p o s t hoc e v a l u a t i o n structure revealed of various measures of orthographic reasonably g o o d c o r r e l a t i o n s w i t h r e a c t i o n t i m e b u t much higher c o r r e l a t i o n s with accuracy. To p r o v i d e a q u a n t i t a t i v e d e s c r i p t i o n o f t a s k a c c u r a c y , we formalized t h e information processing model d e v e l o p e d i n C h a p t e r 1. T h i s model a l l o w s a f o r m a l d e s c r i p t i o n o f t h e f a c i l i t a t i v e e f f e c t of orthographic s t r u c t u r e on both r e a c t i o n time and t a s k a c c u r a c y . The b a s i c a s s u m p t i o n o f t h e model is t h a t k n o wl ed g e o f orthographic structure contributes an independent source of information about the letter string. Consequently, fewer v i s u a l f e a t u r e s a r e n e c e s s a r y t o resolve well-structured s t r i n g s than to resolve poorlystructured strings. The model was a p p l i e d t o t h e t a r g e t s e a r c h t a s k b y f o r m a l i z i n g a d e c i s i o n a l g o r i t h m assu m ed t o b e us ed by t h e s u b j e c t when f a c e d w i t h p a r t i a l information. The model p r o v i d e d a good q u a n t i t a t i v e d e s c r i p t i o n o f t h e r e s u l t s from t h e a c c u r a c y t a s k . The p a r a m e t e r s o f t h e m o d el were

S U M M A R Y AND CONCLUSION

247

psychologically meaningful and the parameter values c o r r e s p o n d i n g t o t h e number o f l e t t e r s s e e n i n t h e t e s t s t r i n g s of t h e c o n t r i b u t i o n of p r o v i d e d a q u a n t i t a t i v e measure orthographic s t r u c t u r e . According t o t h e model, our r e a d e r s were able to recognize two additional letters in we 11-st r u c t u r e d s t r i n g s c o m p a r e d t o poo r l y - s t r uc t u r e d s t r i n g s T h i s i s a s u b s t a n t i a l e f f e c t c o n s i d e r i n g t h a t two l e t t e r s represent one-third of t h e s i x - l e t t e r test s t r i n g . We a l s o c a r r i e d o u t a s e r i e s o f o v e r t j u d g m e n t e x p e r i m e n t s t o assess which d e s c r i p t i o n s o f o r t h o g r a p h i c s t r u c t u r e a r e c o n s c i o u s l y a v a i l a b l e . We asked whether subjects could r e l i a b l y a s s i g n r a t i n g s o f how much a l e t t e r s t r i n g r e s e m b l e s written English on t h e b a s i s of t h e t y p i c a l i t y of t h e l e t t e r sequencing i n t h e test s t r i n g s . In addition, other subjects items on t h e b a s i s of were asked t o d i s c r i m i n a t e t h e rule-governed r e g u l a r i t y o r on t h e b a s i s of s t a t i s t i c a l redundancy. S u b j e c t s ' j u d g m e n t s were more a c c u r a t e l y d e s c r i b e d by rule-governed regularity than by s t a t i s t i c a l redundancy. F i n a l l y , t h e r a t i n g s o f t h e i n d i v i d u a l items c o r r e l a t e d q u i t e s t r o n g l y w i t h t h e i r a c c u r a c i e s and r e a c t i o n times i n t h e target search task. The f a c t o r i a l d e s i g n o f our e x p e r i m e n t s c o n t r a s t e d j u s t one measure of rule-governed r e g u l a r i t y with one measure of s t a t i s t i c a l r e d u n d a n c y . T h e r e f o r e , w e c o n d u c t e d a l a r g e number of post hoc c o r r e l a t i o n a l a n a l y s e s t o e v a l u a t e a wide range of m e a s u r e s o f o r t h o g r a p h i c s t r u c t u r e . The d e p e n d e n t m e a s u r e s were t h e r e a c t i o n t i m e s , a c c u r a c y , a n d r a t i n g r e s p o n s e s t o e a c h of 200 t e s t i t e m s . p o s i t i o n - s e n s i t i v e l o g bigram f r e q u e n c y p r o v i d e d t h e b e s t d e s c r i p t i o n o f p e r f o r m a n c e on t h e i n d i v i d u a l test items. However, o u r r u l e - b a s e d r e g u l a r i t y m e a s u r e a l s o p r o v i d e d a v e r y good d e s c r i p t i o n . In f a c t , our regularity measure c o r r e l a t e d v e r y h i g h l y with t h e b e s t frequency-based measure. T h e r e f o r e , we w e r e n o t s u c c e s s f u l i n c h o o s i n g b e t w e e n rule-governed r e g u l a r i t y and s t a t i s t i c a l redundancy i n t h e s e experiments. We were a l s o a b l e t o e v a l u a t e t h e m o s t a p p r o p r i a t e m e a s u r e s f o r a s t a t i s t i c a l - r e d u n d a n c y d e s c r i p t i o n . We o b t a i n e d information about the u t i l i t y of type versus token counts, t h e appropriate s c a l e f o r describing frequency of occurrence, position-sensitive versus position-insensitive counts of l e t t e r o c c u r r e n c e s , t h e r o l e o f word f r e q u e n c y , a n d t h e r e l a t i v e contributions of various serial positions i n determining t h e o r t h o g r a p h i c s t r u c t u r e o f a n item. What c o n c l u s i o n s c a n b e reached and what a r e t h e implications for future research and classroom

.

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p r a c t i c e ? A l t h o u g h we were n o t s u c c e s s f u l i n c h o o s i n g b e t w e e n rule-governed r e g u l a r i t y and s t a t i s t i c a l redundancy i n t h e s e experiments, a d d i t i o n a l experiments might b e s u c c e s s f u l . Given the b e s t statistical-redundancy measure, i t should be possible t o d e v e l o p a new s e t o f t e s t items t o c o n t r a s t t h i s m e a s u r e w i t h a r u l e - g o v e r n e d r e g u l a r i t y m e a s u r e . We p l a n t o f o l l o w t h e by c o n t r a s t i n g l o g bigram l o g i c of t h e p r e s e n t s t u d i e s f r e q u e n c y an d r e g u l a r i t y m e a s u r e s i n t a r g e t s e a r c h and o v e r t judgment t a s k s . Although t h e s e two measures a r e highly correlated, i t s h o u l d b e p o s s i b l e t o d i s t i n g u i s h b e t w e e n t h em . Given t h e r e s u l t s , i t w i l l still be n e c e s s a r y t o c a r r y o u t p o s t h o c c o r r e l a t i o n s t o d e t e r m i n e i f some o t h e r m e a s u r e m i g h t provide even a b e t t e r d e s c r i p t i o n . This research has the promise of l e a d i n g t o t h e d e s c r i p t i o n t h a t b e s t r e f l e c t s t h e kn o wl ed g e o f o r t h o g r a p h i c s t r u c t u r e u s e d i n t h e c o u r s e o f normal r e a d i n g . A r r i v i n g a t a good d e s c r i p t i o n o f o r t h o g r a p h i c s t r u c t u r e should b e b e n e f i c i a l i n t h e development of reading i n s t r u c t i o n . Given t h a t t h e u t i l i z a t i o n of o r t h o g r a p h i c s t r u c t u r e is a n important co m p o n e n t in letter and word recognition, i n s t r u c t i o n a l m a t e r i a l s should be designed t o f a c i l i t a t e c h i l d r e n ' s understanding of t h i s s t r u c t u r e . Current phonics p r o g r a m s a d d r e s s o n l y t h e c o r r e s p o n d e n c e s b e t w e e n s p e l l i n g and sound, n o t t h e c o n s t r a i n t s i n English orthography. Y a s s a r o and T a y l o r ( 1 9 7 9 ) s k e t c h a s e r i e s o f c l a s s r o o m g am es t h a t m i g h t b e employed t o t e a c h c h i l d r e n common l e t t e r p a t t e r n s a n d t h e l o c a t i o n s i n words t h e s e l e t t e r p a t t e r n s a r e most l i k e l y t o b e found. D e l i n e a t i n g t h e b e s t description of orthographic s t r u c t u r e m i g h t f a c i l i t a t e t h e t e a c h i n g an d l e a r n i n g o f t h i s structure

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Glossary a c c u r a c y t a s k : a t a s k i n which accuracy is t h e primary dependent measure; i n the target search task, average p e r f o r m a n c e i s m a i n t a i n e d a t 7 5 % c o r r e c t by a d j u s t i n g t h e d u r a t i o n of t h e t e s t s t r i n g and/or t h e p r o c e s s i n g time available. a n ag r am : a p e r m u t a t i o n o f t h e l e t t e r s c o m p r i s i n g a word. bigram: a t w o - l e t t e r

cluster.

catch t r i a l : --

a t r i a l d u r i n g which t h e t a r g e t l e t t e r d o e s appear in t h e test s t r i n g .

not

feature detection: a p r o c e s s which answers t h e q u e s t i o n of w h e t h e r o r n o t a p a r t i c u l a r f e a t u r e is p r e s e n t a n d / o r p r o v i d e s i n f o r m a t i o n a b o u t t h e d e g r e e t o which t h e f e a t u r e is present. fourier analysis: t h e d e s c r i p t i o n of a v i s u a l d i s p l a y i n terms o f i n t e n s i t y a n d f r e q u e n c y o f c o m po n en t s i n e w av es. f u l l report: g i v e n a d i s p l a y o f items, s u b j e c t s a r e asked r e p o r t a l l o f t h e items i n t h e d i s p l a y . g e n e r a t e d a b s t r a c t memory: modality-free a n a l o g o u s t o s h o r t - t e r m memory.

(abstract)

graphemic c o n s t r a i n t s : see s c r i b a l c o n s t r a i n t s .

263

to

storage,

264

GLOSSARY

high s p a t i a l f r e q u e n c i e s : t h e h i g h f r e q u e n c i e s o f analyses of a visual display. homophones: d i f f e r e n t w o r d s such as right/write.

t h a t a r e pronounced

a

fourier

identically,

i n f o r m a t i o n : s o u r c e o f knowledge a v a i l a b l e t o t h e r e a d e r ; for example, t h e f e a t u r a l information i n p r e p e r c e p t u a l s t o r a g e o r t h e r e a d e r ' s memory o f l e t t e r p a t t e r n s i n t h e l a n g u a g e . l e x i c o n : s t o r a g e o f p e r c e p t u a l and c o n c e p t u a l c o d e s o f w o r d s i n l o n g - t e r m memory; e a c h word h a s p e r c e p t u a l c o d e s s u c h a s t h e s o u n d and v i s u a l p a t t e r n o f t h e word and c o n c e p t u a l codes such a s its meaning. l o n g - t e r m memory: r e l a t i v e l y permanent s t o r e of knowledge t e r m o f c o d e s , r u l e s , and p r o c e d u r e s ( s c h e m a t a ) .

low s p a t i a l

f r e q u e n c i e s : t h e low f r e q u e n c i e s a n a l y s i s of a v i s u a l display.

of

a

in

fourier

morpheme i d e n t i t y : r e t e n t i o n of spelling similarity s e m a n t i c a l l y - r e l a t e d words, such a s cone/conic.

of

nonword: a l e t t e r s t r i n g t h a t d o e s n o t s p e l l a word; s o m e t i m e s u s e d t o mean t h a t t h e l e t t e r s t r i n g a l s o d o e s not c o n f o r m t o s t a n d a r d English s p e l l i n g , i.e., i t v i o l a t e s English orthography. orthographic regularity: d e s c r i p t i o n of orthographic s t r u c t u r e b a s e d upon r u l e s and g e n e r a l i z a t i o n s a b o u t t h e o b s e r v e d p a t t e r n s of English orthography; a l s o referred t o a s rule-based description. orthographic structure: the spelling constraints i n a written language; i n E n g l i s h , f o r example, g i v e n i n an i n i t i a l p o s i t i o n , r i s more l i k e l y t o f o l l o w t h a n 2. o v e r t judgments: judgments about the s p e l l i n g of l e t t e r s t r i n g s ; s t u d i e d t o a s s e s s what knowledge of o r t h o g r a p h y is c o n s c i o u s l y a v a i l a b l e a n d c a p a b l e o f r e p o r t . p a r a l l e l processing: when i n f o r m a t i o n a b o u t two o r m o r e is processed simultaneously.

items

GLOSSARY

265

perceptual recognition: see primary recognition. phonological constraints: the constraints on English orthography that derive from the allowable sequences of sounds in English words. positional frequency: see position-sensitive measure. position-dependent measure: see position-sensitive measure. position-independent measure: see position-insensitive measure. position-insensitive measure: a statistical-redundancy description of orthographic structure which counts letter sequences on the bases of occurrence in words of specific lengths without regard to position of occurrence; also referred to a s position-independent measure. position-sensitive measure: a statistical-redundancy description of orthographic structure which counts letter sequences on the basis of occurrence in specific positions in words of specific lengths; also referred to as position-dependent measure or positional-frequency. postcue: when a target letter follows a test string. precue: when a target letter precedes a test string. preperceptual visual storage: holds features passed on feature detection for roughly one quarter of a second.

by

primary recognition: joint evaluation and integration of the features in preperceptual storage and knowledge of orthographic structure in long-term memory; the outcome is a synthesized percept; also referred to as perceptual recog n i t ion. probabilistic description: see statistical redundancy. pseudoword: a nonword that conforms to English spelling. reaction time (RT) task: task in which reaction time is the primary dependent measure; in the high-accuracy target search task, for example, accuracy is kept near perfect by

266

GLOSSARY

keeping t h e interval.

test

string

present

r e g u l a r it y : see o rthog r a p h i c r e g u l a r i t y

during

the

response

.

r u l e-based d e s c r i p t ion: see o r thog r a p h ic r e g u l a r it y

.

scribal constraints: the constraints in the selection of letters for either representing sounds o r marking graphemic, graphotactic , o r morphological functions; a l s o referred t o a s graphemic c o n s t r a i n t s . secondary recognition: transforms v i s u a l percept held in s y n t h e s i z e d memory i n t o meaning h e l d i n g e n e r a t e d a b s t r a c t memory. single-letter positional frequency: t h e frequency w i t h which a l e t t e r o c c u r s i n a s p e c i f i c p o s i t i o n i n words o f a s p e c i f i c l e n g t h i n a sample of t e x t . s p e e d e d fl task: s u b j e c t s a r e i n s t r u c t e d t o r e s p o n d m o r e in the q u i c k l y t h a n t h e time n e e d e d f o r h i g h a c c u r a c y ; t a r g e t s e a r c h t a s k , s u b j e c t s l e a r n t o respond i n synchrony w i t h a n e x t e r n a l s i g n a l whose r e l a t i v e o n s e t i s a d j u s t e d t o k e e p p e r f o r m a n c e a t 7 5 % c o r r e c t ; b o t h a c c u r a c y an d RT a r e evaluated a s dependent measures. of s t a t i s t i c a l redundancy: category of descriptions o r t h o g r a p h i c s t r u c t u r e d e r i v e d from c o u n t s o f l e t t e r s o r l e t t e r sequences occurring in t h e w r i t t e n language; a l s o called probabilistic description. ~ summed_c o u n_ t s : t h_ e sum o f i n d i v i d u a l f r e q u e n c i e s o f t h e l e t t e r s o r letter clusters i n a l e t t e r string.

s y n t h e s i z e d v i s u a l memory: h o l d s p e r c e p t u a l o u t c o m e s o f p r i m a r y recognition process. target letter: i n t h e t a r g e t s e a r c h t a s k , t h e l e t t e r whose presence o r absence i n t h e t e s t s t r i n g of l e t t e r s must b e reported

.

target -

s e a r c h~ task: t h e s u bj e c t i s g i v e n a t a r g e t l e t t e r and t h e t a s k is t o i n d i c a t e whether o r n o t t h e t a r g e t l e t t e r is contained i n a t e s t s t r i n g of l e t t e r s .

GLOSSARY

267

test string: i n the t a r g e t search task, the l e t t e r s t h a t m u s t be e v a l u a t e d i n t e r m s o f p r e s e n c e o r a b s e n c e o f t h e t a r g e t letter. t o k e n c o u n t : a c o u n t b a s e d on t h e number of t o t a l o c c u r r e n c e s -o f an i t e m ; f o r e x a m p l e , t h e t o t a l number o f o c c u r r e n c e s o f a l l words c o n t a i n i n g a p a r t i c u l a r l e t t e r . trigram: *e

a three-letter

cluster.

count: a c o u n t b a s e d on t h e number o f u n i q u e o c c u r r e n c e s o f an item; f o r e x a m p l e , t h e number o f u n i q u e words containing a particular l e t t e r .


Author Index A

Adams, N., 5 8 , 67 A l l p o r t , A., viii A n d e r s o n , I . H., 1 1 - 1 2 A n i s f e l d , M. A . , 25 A t k i n s o n , R. C . , 56 B

B a d d e l e y , A . D . , 7 , 64 B a r b u t o , P . F . , 27 B a r o n , J , , viii, 6 2 B e a l , A. L . , 2 4 B j o r k , E. L . , 62 Bouma, H., 1 2 , 1 5 - 1 6 , 43-45, B o u w h u i s , D . , G . 26 B r e i t m e y e r , B . G., 1 9 B r o a d b e n t , D. E . , 1 9 , 1 4 1 , B r o w n e l l , H . , 58, 67 B r u n e r , J. S., 6 , 2 4 Byrnes, J., 24

52-53

C

C a r r , T. H . , i x C a t t e l l , J . M., 1 1 - 1 2 C h a n d l e r , J . P . , 59 Chomsky, N . , 35 C l a r k , H . H . , 51 269

270

AUTHOR I N D E X

C o n g e r , B. , 1 3 2 Creelman, C. D.,

93

D D e a r b o r n , W.

F.,

11-12

E

E g e t h , H. E s t e s , W.

25 v i i i , 5, 62

E., R.,

F F a n t , C. G . M . , F r a n c i s , W. N.,

14 26-27,

126-127,

149

G

Ganz, L., 1 9 G e o f f r i o n , L. D . , 5 G i b s o n , E . J . , v i i i , 1, 1 5 , 2 5 , 29-38, G i l m o r e , G. C., 25 Green, D. M . , 1 7

H Halle, M., 14 Hammond, M., 2 5 , 29-30 H a v i l a n d , S . E . , 58, 67 Henderson, L., v i i i Huey, E . B . , 1, 1 3 Hung, D. L . , 2 9 J

,

J a k o b s o n , ' R. 14 J o h n s o n , N. F., v i i i J o h n s t o n , J. C . , 2 6 , 1 0 1 , 1 3 2 J o n e s , R. D . , 7 4 , 77-18 J u e l , C. L.r 27 J u o l a , J. F., 56, 68

32

AUTHOR INDEX

K

Kallrnan, H. J . , 5 8 K a u s l e r , D. H., 3 3 K i n g , J. F . , 2 7 Klitzke, D., 105 Kleiman, G. M . , 2 9 K o l e r s , P . A., 1 0 8 K r u e g e r , L. E . , v i i i , 7, 4 7 K u c e r a , H., 2 6 - 2 7 , 1 2 6 - 1 2 7 , 1 4 9 K u r a t h , H., 3 5 L

L a n d a u e r , T. K . , 2 7 - 2 8 L e f t o n , L. A., 2 4 L e v i n , H., viii, 1 Levy, B. A . , 2 9 L e w i s , S. S., 2 9 - 3 0 Lipscomb, c . , 7 4 , 7 7 - 7 8 Lorge, I . , 2 5 M

Macey, W. H., 2 7 Mason, M . , 2 6 , 3 7 - 3 8 , M a s s a r o , D. W.,ix, 2,

132 5-8, 56-58, 62,

1 7 , 19, 2 1 , 2 6 , 2 9 , 38-47, 43, 74, 77-78, 96, 105, 246, 248 Mayzner, M . S . , 26, 4 8 , 9 1 McClelland, J . L . , 26, 1 0 1 , 1 3 2 Newhort, D, J . , 2 4 Meyer, D. E . , 7 4 , M i l l e r , G. A., 6 , 2 4 M i l l e r , T. J . , 6 8

N Neisser, U.,

14,

43

0

Oden, G . C . , 2 1 , O l i v i e r , D. G . , 1 2 7 - 1 2 8 , O l s e n , G. A . , 3 3

131

271

AUTHOR INDEX

272

Osser, H . ,

1 5 , 2 5 , 29-30

P P i c k , A . , 2 5 , 29-30 P o d g o r n y , P., 1 3 1 P o l l a t s e k , A . , ix P o s t m a n , L . , 6 , 2 4 , 27-28, P y l e s , T., 32

131-132

R

R e d e r , L. M . , 5 8 , 6 7 R e e d , A. V., 7 5 , 1 0 5 R e i c h e r , G. M., 6 , 6 2 R u b e n s t e i n , H . , 29-30 R u b e n s t e i n , M . A . , 29-30 Ruddy, M. G., 74 S

S a v i n , H. B . , 27-28 S c h i f f , W., 15 S c h m u l l e r , J., 7 , 1 7 , 1 9 , 4 3 S c h o l z , R. , 7 4 , 77-78 S c h u l z , R. W., 25-26 S c h v a n d e v e l d t , R. W., 7 4 S e l f r i d g e , 0. G., 1 4 S h a n n o n , C. E., 6 , 24 S h a p i r o , R . G., 7, 47 S h e b i l s k e , W. , 3 S h e p a r d , R. N., 1 3 1 S h u r c l i f f , A . , 25-26, 29-30, 1 3 2 S i d m a n , M., 47 S k a a r , E., 6 2 S m i t h , E. E., 4 , 29-30, 5 8 , 6 7 , 1 3 2 S m i t h , J., 15 S o l o m o n , R. L . , 27-28, 1 3 1 S o l s o , R. L., 27 S p e n c e r , H . , 11-13 S p o e h r , R. T., 1 3 2 S p r a g i n s , A. B., 2 4 S p r e e n , O., 26 S t r e e t e r , L. A . , 27-28 S w e t s , J. A . , 1 7

AUTHOR I N D E X

27 3

T T a y l o r , G . A . , 26, 3 8 - 4 7 , 5 7 - 5 8 , 1 3 1 , 248 T h o m p s o n , M. C . , 6, 5 7 - 5 8 , 6 2 T h o r n d i k e , L. L . , 2 5 T h u r s t o n , I . , 62 T i n k e r , M. A . , 11 T o w n s e n d , J . T . , 15 T o p p e r , G. E . , 27 T r a v e r s , J. R . , 127-128, 1 3 1 T r e s s e l t , M. E . , 2 6 , 48, 9 1 T u l v i n g , E., 6 T u r v e y , M. T . , 56 T z e n g , 0. J . L . , 2 9

68,

93,

105,

U

U n d e r w o o d , 8. J . ,

25-26

V

Vachek, J., V e n e z k y , R.

33 L.,

26,

29,

31,

W

W a l l a c h , M. A . , 24 Wang, W. S-Y., 29 W h e e l e r , D. D . , 6, 6 2 W h o r f , B. L . , 35 W o l i n , B. R . , 2 6 W o o d w o r t h , R. S., 3

Y

Y onas, A . ,

25-26,

29-30,

132

33,

35,

38-47,

57-58,

96


Subject Index A

a c c u r a c y t a s k , 40,47-48, anagram, 38 a w a r e n e s s , 81

56-61,

246-247

B b i g r a m , 25-29 bigram c o u n t s ,

60-244

c c a t c h t r i a l , 39 c l a s s r o o m p r a c t c e , 779 c o n f u s i o n m a t r i c e s , 14-15 c o n s o n a n t s p e l l i n g , 31-32

D d e c i s i o n , 1 7 - 1 8 , 5 6 , 57 d ' m e a s u r e , 17-18

E E n g l i s h n e s s , 127-128 e n v e l o p e , 15-16, 1 9

275

276

SUBJECT INDEX

F f e a t u r e a n a l y s i s , 2 , 13-14 f e a t u r e d e t e c t i o n , 3-4, 19-21 f e a t u r e d e t e c t i o n s t r a t e g y , 43-46, f e a t u r e s , 3 , 5 , 1 4 , 14-21 fourier analysis, 19 f r e q u e n c y s c a l e , 130-132 f u l l r e p o r t , 6 , 24-25

6 8 , 71-73

G

g e n e r a t e d a b s t r a c t memory, 8

H high s p a t i a l f r e q u e n c i e s , 19 homophones, 33

i n f o r m a t i o n , 2 , 73-74 i n f o r m a t i o n p r o c e s s i n g m o d e l , 1-8, 55-62,

K k n o w l e d g e , 2 , 74

L l e g i b i l i t y of t e x t , 11-13 l e t t e r - s o u n d c o r r e s p o n d e n c e s , 29-30 lexicon, 8 l i n g i u s t , 34 l o n g - t e r m memory, 3 , 8 low s p a t i a l f r e q u e n c i e s , 1 9

M m a s k i n g s t i m u l u s , 6 , 1 5 , 1 7 , 40 memory, 2-3 morpheme i d e n t i t y , 32 m o r p h e m i c f e a t u r e s , 32-33

66-67

S U B J E C T INDEX N n o n w o r d , 25

o r d e r e d a p p r o x i m a t i o n s t o E n g l i s h , 24-25 o r t h o g r a p h i c r e g u l a r i t y , 38 o r t h o g r a p h i c s t r u c t u r e , 2 , 4-9, 2 3 - 3 6 , 245 o v e r t j u d g m e n t s , 8 1 - 9 0 , 247

P p a r a l l e l p r o c e s s i n g , 5 , 56 p a i r e d j u d g m e n t s , 81, 87-89, 120-123 perceptual recognition, 8 perceptual unit, 5 p e r i p h e r a l v i s i o n , 13, 15, 19 p h o n o l o g i c a l c o n s t r a i n t s , 30-31 p h o n o l o g i c a l l y - b a s e d d e s c r i p t i o n s , 29-30 p o s i t i o n - i n s e n s i t i v e measure, 132 p o s i t i o n - s e n s i t i v e measure, 132 p o s t c u e , 47-48, 62-66 p r e c u e , 4 7 - 4 8 , 62-66 p r e p e r c e p t u a l v i s u a l s t o r a g e , 3-4, 56 p r i m a r y r e c o g n i t i o n , 4-5, 7 - 8 , 5 6 p r i m i n g , 74 p r o c e s s , 2-3 p r o c e s s i n g time, 1 4 p s e u d o w o r d s , 2 4 , 8 2 - 8 5 , 115 p s y c h o l o g i s t s , 34

R r a t i n g s , 8 1 , 8 1 - 8 7 , 113-119 r e a c t i o n - t i m e t a s k , 3 7 - 3 8 , 4 7 - 4 8 , 6 8 - 6 1 , 246-247 r e a d i n g , 1-2 r e a d i n g i n s t r u c t i o n , 1 - 2 , 247-248 recoding, 8 redundancy, 6 rehearsal, 8 R e i c h e r - W h e e l e r p a r a d i g m , 6 - 7 , 40 r u l e - b a s e d d e s c r i p t i o n , 2 3 - 2 4 , 30-36, 3 8 , 9 6 , 1 2 9 , 247 r u l e - g o v e r n e d r e g u l a r i t y , 23-24, 30-36, 3 8 , 9 6 , 1 2 9 , 247

277

SUBJECT INDEX

278

S saccades, 3 s c r i b a l c o n s t r a i n t s , 31-32 secondary recognition, 4 , 8 s h o r t- t e rm memo r y , 7-8 s i m i l a r i t y , 4 3 - 4 6 , 5 1 - 5 4 , 64-65, 72-73 s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y , 3 7 , 48 s i n g l e - l e t t e r p o s i t i o n a l f r e q u e n c y c o u n t s , 149-159 speed-accuracy paradigm, 75 s p e e d e d RT t a s k , 75-82 s t a g e o f p r o c e s s i n g , 2-3 s t a t i s t i c a l r e d u n d a n c y , 23-29, 247 s t i m u l u s items, 97-98, 143-148 summed c o u n t s , 37 s y n t h e s i z e d v i s u a l memory, 8 , 56

T t a r g e t l e t t e r , 37-39 t a r g e t s e a r c h t a s k , 3 7 , 37-81 t a r g e t t r i a l , 39 template, 14 t e s t s t r i n g , 37-39 t o k e n c o u n t , 27-28, 128-130 t r i g ram , 2 7 t y p e c o u n t , 27-28, 128-130

V v o w e l s p e l l i n g s , 31-32

w word f r e q u e n c y , 1 4 1 word r e c o g n i t i o n , 1 - 2 ,

4

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