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JOURNAL OF SEMANTICS AN INTERNATIONAL JOURNAL FOR THE INTERDISCIPLINARY STUDY OF THE SEMANTICS OF NATURAL LANGUAGE MANAGING EDITOR:

Peter Bosch

EDITORIAL BOARD:

Simon C. Garrod Leo G.M. Noordman Pieter A.M. Seuren

REVIEW EDITOR:

Rob A. van der Sandt

ASSISTANT EDITOR:

Bart Geurts

CONSULTING EDITORS:

W. Levell (Max Planck Inst. Nijmegen),

J. Allwood (Univ. Goteborg),

J. Lyons (Trinity Hall, Cambridge),

R. Bartsch (Amsterdam Univ.),

W. Marslen-Wilson (Max Planck Inst. Nijmegen),

J. van Benthem (Groningen Univ.),

J. McCawley (Univ. Chicago),

H.E. Brekle (Univ. Regensburg), G. Brown (Univ. of Es�x),

B. Richards (Edinburgh Univ.),

H.H. Oark (Stanford Univ.),

R. Rommetveit (Oslo Univ.),

H.-J. Eikmeyer (Univ. Bielefeld),

H. Schnelle (Ruhr Univ. Bochum),

G. Fauconnier (Univ. de Vincennes),

J. Searle (Univ. Cal. Berkeley),

P. Gochet (Univ. de Liege),

A. von Stechow (Univ. Konstanz),

J. Hintikka {Florida State Univ.),

M. Steedman (Edinburgh Univ.),

St. lsard (Sussex Univ.),

G. Sundholm (Nijmegen Univ.),

D. Israel (SRI, Stanford)

Ch. Travis (Tilburg Univ.),

P.N. Johnson-Laird (MRC Appl. Psych.

B. van Fraassen (Princeton Univ.),

Umt, Cambridge),

Z. Vendler (UCSD),

E. Keenan (UCLA),

Y. Wilks (New Mexico State Univ.),

S. Kuno (Harvard Univ.),

D. Wilson (UCL).

EDITORIAL ADDRESS:

Journal of Semantics, P.O. Box 1454, 6501 BL Nijmegen, The Netherlands

Published by Faris Publications,

P.O. Box () N.I.S.

ISSN

509, 3300 AM

Foundation 0167·5133

Printed In the Netherlands by ICG

Dordrecht, The Netherlands.

Printing

FORIS BOOKS the expert-system type of lexicographic facilities

WORD EXPERT SEMANTICS

used lor building up the knowledge base The

An lnterllngual Knowledge-88Hd

languag�reontrastive nature of the system de­

Approach

scribed Is underlined by the ex1enslve use of en 1986

Bart C. Papegaa1j

Bnd. 011.120,­ Pap. on. 57,-

X+ 254 pp.

ISBN 90 6765 262

ISBN 90 6765 261

3 X

In computational linguistics, stud1es of semantics are usually directed at the interpretation of func­ tion words, notably quantifiers and connectives. Typically, the problems dealt with in current lor­ mal or logical semantics are grosso modo invar­

Intermediate language based on Esperanto. A final chapter provldas an outlook on future de­ velopments In computerized lexicography, sell­ learning sy1ems and other aspects of language technology. The general approach is in line with a trend in the field of machine translation to shift the locus of attention from the grammar formalism to the dic­ tionary, and beyond, to systems increasingly based on artificial Intelligence.

Iant with respect to language translation. The present work addresses the semantics of

Contents:

content words, in particular the relation between

Introduction

lexical and conceptual fields and how this relation

Part

varies among languages. From a background of

Ambiguity

machine translation and contrastive lexicology,

Chapter 1: Natural Language Processing/Chapter 2: Lexical Ambiguity/Chapter 3: A Concise His to­

the author presents a framework lor contextual

1:

Machine Translation and the Problem of

neal Survey/Chapter

resolution of lexical ambiguities. This framework relies on a knowledge base of

4:

MT

&

Understanding -

Contemporary Techniquas/Chapter 5 The Im­

lexical universes or word experts: clusters of non­

portance of the Dictionary/Chapter 6: The Need

linguistic

lor Integration

information

such

as

hyperonyms,

exemplary slot fillers lor thematic roles, and other

Part II: The Semantic Word Expert System

word associations. The general set-up of these

Chapter 1: General Lay-out of the DLT System/

word experts has partially been derived from the

Chapter 2: The Structure of the Lexical Know­ ledge Bank/Chapter 3: Disambiguation with

definition-with-examples formula of conventional

SWESIUChapter 4·

diction arias. A central element in the book is the notion of

The Disambiguation Dia­

logue

dependency pairs, atomic chunks of ontological

Part Ill: The Semantic Work Bench- A Develop­

or contextual knowledge. These are grouped into

ment Tool

lexical universes, which in turn make up a seman­

Chapter

tic network of taxonomic relations. The depen­ dency pair arrangement constitutes a basis lor

1:

Developing SWESIL and the LKB/

Chapter 2: The Semantic Work Bench/Chapter 3: Tests and Results/Chapter 4: Melby Test Results.

IV:

relined pattern matching of alternative interpreta­

Part

tions, consecutive to the strictly syntactic parae

Chapter 1: Computer-Lexicography/Chapter 2:

of a sourca language text fragment. The result is a mechanism lor word sense compu­

Future Developments

Macrocontext and Discourse Analys1s!Chapter 3: The Self-Improving System/References

tation which is probabilistic and complementary to interactive disambiguation in a semi-automatic

" ... instructive reading lor system designers and

translation system.

students of computational linguistics... "

The book discusses the design philosophy and

functioning of the word expert system, as well as

F. E. Knowles, MA, MSc, Professor Aston University, Birmingham.

FORIS PUBLICATIONS HOLLAND/USA Available at your bookstore or direct from: FOAlS PUBLICATIONS HOLLAND 509 - 3300 AM Dordrecht - tel. (0)78-510454

P.O. Box

P.O. Box

FORIS PUBLICATIONS USA. Inc. 5904 - Providence Rl 02903 tel. (401 )232-2722 -

or

of Langu•ge,

FORIS BOOKS FORTHCOMING

STUDIES IN DISCOURSE REPRESENTATION THEORY AND THE THEORY OF GENERALIZED QUANTIFIERS Jeroen Groenendljk and Martin Stokhof, (eds.)

FOUNDATION S OF PRAGMATICS ANDLEXCIAL SEMANTICS Jeroen GroenendijkandMartin Stokhof(eds) 1986

Bnd. Pap.

±170 pp.

ISBN90 67652644 ISBN 90 67652652

The papers collected In this volume center around two themes: lexical semantics. and pragmatics

1986

Bnd. Pap.

±200pp.

ISBN 90 67652660 ISBN 90 67652679

The papers collected In this volume are contribu­ tions to the theory of generalized quantifiers and discourse representation theory, two major Inno­ vative theories In natural language semantics of recent origin. Topics treated Include: a procedural view on generalized quantifiers; expresalblllty and

They deal with theoretical Issues as well as with

constraints on lexical meaning; 'phase' quantifica­

descriptive topics. Including contextual dimen­

tion; the analysis of aspectual oppositions; the

sions In lexical meaning; the location

relation between referential and quantifier mean­ Ings of descriptions and Indefinite NPs; type-free

of

events;

composltlonallty In morphology; the eplstemlc meaning of Japanese particles; the status of the

theories for natural language semantics; VP-Inter­

meaning postulates; the projection problem of pre­

pretatlon In a compositional discourserepresenta­

supposition; Informational paradoxesandtheorles

tion theory; and dlscourserepresentatlontheory as

of Information representation In possible world

part of a phenomenological theory of belief.

semantics This book will be of interest to scholars and ad­

This book will be of Interest to scholars and ad­ vanced students in theoretlcal linguistiC/1, philoso­

vancsd students in theoretical lingulatics,phlloso­

phy of language, and phliosophical loglc.

phy ollanguage, and philosophical logic. Contents: Preface/Johan van Benthem: Semantic Automa­

Contents: Preface/Renate Bartsch: Context-dependent In­

ta/Edward Keenan: Lexical Freedom and Large

terpretation of Lexical Items/ A/Ice tar Meulen: Lo­

Categorles/Sebest/an L6bner: Quantification 8!1 a

cating

Composltio­

Major Module of Natural Language Semantics/

nallty and the Syntax of Words/ Ken-lchlro Shirai:

Hank Verkuyl: Non- (Ia A:::::> I a B) I a(A AB) = (Ia A Ala B) I aT, if T is a tautology

While (II) and ( 12) seem quite natural, (13) is clearly problematic. Is it really true to say of each agent a that he or she imagines that Bacon is Shakespeare or Bacon is not Shakespeare? Perhaps our agent a has not ever even heard about these two remarkable historical characters. How could they then play any role in his or her imagination? These questions are related to the famous problem of 'logical omniscience' in epistemic logic: K aT holds for every tautology T. Hintikka (1975) and Rantala ( 1 982) have shown h ow to avoid this undesirable consequence of(3). Thus, Rantala's technique of impossible worlds could be adapted to the logic of I a, so that we get rid of (13). The problem of logical omniscience is one of the motivations for the situation semantics that Barwise and Perry have developed as an alternative to

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i.e., p is true in all the q>-worlds in A�, I criterion. The second was the interpretability of the factors . InTable 3 some results are presented.The coefficients of congruence indicate the in variance of the factors.Those above .80 may be considered reli­ able, those between .71 and .79 as moderately reliable, and those below .71 as unreliable.

Main Task

Subjects and Procedure: In this task 150 subjects took part. Most of them were students from the Social Science departments. The subjects sorted the 226 factors according to the Miller Procedure. The mean number of categories was 24.7 with a standard deviation of 14.6. The sorting results were subjected to factor-analysis.

Sam pte• Means Sd's Factors•• % of var.

18.7 9. 1 25 63

2

3

4

5

6

7

8

9

10

1 8.4 9.4 25 63

1 7.6 9.2 27 66

1 3. 7 7.5 22 63

24.4 1 2.8 28 62

1 8.4 1 0.0 27

19.5 9.4 25

64

64

1 8.2 1 0.9 23 65

1 9.0 9.0 25 65

23.4 1 2. 2 27 62

Coefficients of Congruence (CC) CC>.79 . &O>CC>.70 . 7 l>CC

16 2 7

14 4 7

12 5 10

10 4 8

14 3 II

7 4 16

II 4 10

12 2 9

13 2 10

10 4 13

Number of Factors used•••

23

25

24

19

25

23

23

17

23

24

(•) (••) (•••)

The number of verbs in the samples I to 6 was 1 00; for the samples 7 to 10 the numbers were 98, 96, 96, 96 respectively. The total number offactors was 254 See "Main Task"

Table 3: Mean number of categories, standard deviations of number of categories, number of principal components with Eigenvalues> I , percentage of variance persubjects,andcoefficientsof congruence

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Not all of the factors obtained in the subtasks were useful for the main task. In the first place only those factors were considered that had at least two verbs with a loading > .40. In the second place, those verbs were deleted that had a higher loading on another factor. After this, factors in which at least two verbs were left with loadings > .40 were retained. These factors were repre­ sented on cards by the 2, 3, or 4 highest loading remaining verbs. The result was that of the 254 original factors, 226 were retained.

23 1

Results: Principal Components Analysis yielded 1 5 factors meeting the eigen­ value criterion of 2.5. These factors were rotated according to Varimax. The total amount of variance explained by these factors was 4 1 %. The 15 factors are to be conceived of as the basis for the required method of data-collecting. Interpretation of the factors based on the loadings which exceeded .40 are provided in Table 4 (in capitals). From each of the 15 factors three groups of verbs were selected, each group consisting of three verbs. The list of 45 groups of three verbs each ( cf. Table 4) constitutes the method for the description of social acts. Only those verbs were incorporated into that list that are both most consistent with and most homogeneous with respect to the central meanings ( interpretations) of the factors.

The 15 Factors that came about on the basis of similarity in meaning can be regarded as a two-way account. On the one hand, they tell us what semantic 'junctions' are encoded in the language system. These semantic junctions represent the meaning potential for encoding in language the 'moves' in discourse situations. On the other hand, these semantic junctions represent a set of options available to the social agent, belonging to the repertoire of human beings. They indicate what agents can do in discourse-situations. Since the verbs were selected on the basis of the two characteristics "social" ( two or more persons presupposed) and "intentionality", the set of options can be called the "dramatist potential" of social agents. It should be noted that the list does not contain verbs denoting 'internal' acts such as hope, desire, think,feel, know, doubt. It is particularly the "social" criterion that causes an important difference between the present structure and other lexicons of verbs or structures ( e.g. Kiesler 1 983; e.g. Ballmer & Brennenstuhl 1 98 1 ). The list reflects fairly well both in number and in substance the array of categories which make up the so-called "interpersonal circle" ( Kiesler 1983; cf. Benjamin 1 974), notwithstanding the fact that this 'circle' reflects a personological orientation. The circle represents a two-dimensional space reflecting the joint action of two basic interpersonal dimensions, namely, Control (Dominance versus Submission) and Affiliation ( Love versus Hate). On the circular continuum 16 categories are located at polar ends represent­ ing semantic opposites. For Dominance and Submission there are synonyms or near-synonyms in the factors III (Authority) and XIII (Docility), respecti­ vely. For Love and Hate there are synonyms or near-synonyms in the factors V and VII ( Love and Protection) and in the factors I and X ( Verbal and Physical Aggression). The other factors can be considered blends of the two dimensions. Sociability (II), Emotional Demand ( IV}, Argumentation ( VI), and Edification ( XI) can be located between Dominance and Love; Obscurity ( VIII), Aloofness ( XII), and Restoration ( IX) between Hate and Submission;

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Discussion

232

VERBAL A GGRESSION

I call a p. nam�s. iflnllt, curs� 2 blow a p. up, snap at a p., abus� 3 sw�ar at, storm and rag�. scold

II

SOCIABJUTY

I grut, �nurtain, agru 2 hav� a chat, g�t into touch wuh, join 3 call on, associate with, mak� acquaintanc�

Ill

A UTHORITY

impau. summon, d�mand 2 send for, prns a p., dicta/� 3 ordain, hold r�sponsibl� for, influ�nce

IV

EMOTIONA L DEMAND

I whine, lament, cha11er 2 brag, whim�r. put on airs 3 complain, sulk, hav� one's way

v

L O VE

I fondle, embrac�. ogle 2 car�ss, coddl�. seduce 3 hug, kiss, make lov� to

VI

ARGUMENTA TION

argu�. pos�. m�ntion 2 matntain, b�ar witnns to, propagatt 3 emphasiu, object, confirm

Vll

PROTECTION

I look afttr, prottct, support 2 comfort, tak� pity on, put heart into a p. 3 assist, help, r�=re

Vlll

OBSC URITY

I obscure, distort, �mbezzl� 2 secr�l�. devise, trifl� 3 disguise, spirit away, kup back

IX

RESTORA TION

I r�stor�. r�dum, pay 2 buy off, fork out, �xcuu 3 do p�nance, ransom, ind�mnify

X

PHYSICAL A G GRESSION

torture, molest, hit 2 kidnap, torment, overpower 3 injure, auack, defy

XI

EDIFICA TION

tnstruct, giv� lessons, advise 2 sketch, tnform, show 3 coach, illustratt, explatn

X/I

ALO OFNESS

I s�c/ude o.s., be non-commiued, escape 2 abandon, dissociate from, keep aloof 3 kup to o.s., stand mutt, pipe down

X/II

DOCILITY

I acquit o.s. wdl, put up with, capitulatt 2 climb down, control o.s., take as one's due 3 comply with, swallow, give a lurch

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I

233 XIV

COMPETITION

I com�ll!. ddi�ra/1!, stand up to 2 play a trump, outbid, bet 3 chall�ng�. disput�. bargain

XV

A PPRAISAL

I �xtol, pralu, back a p. 2 comm�nd, applaud. chur 3 congratulat�. crack up, pay homag� to

� ) Translation by the author

Tab/� 4: Factor Labels and Rating Scales for Social Acts•

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Competition ( XIV) between Hate and Dominance, and Appraisal ( XV) bet­ ween Love and Submission. Interpersonal behaviour can be described by different kinds of terms, at different levels of abstraction, and from different theoretical perspectives. In pursuing a circumplex structure, Wiggins (1979, 1980), for example, restrict­ ed himself to the interpersonal trait domain, thereby choosing for a rather abstract level of categories within the field of person-cognition ( cf. Kiesler 1983). Bochner et a!. (1977) derived a circumplexically ordered taxonomy of interpersonal behaviour, on the basis of self- and other-ratings on Lorr & McNair's (1965) Interpersonal Behavior Inventory. This inventory consists of statements that have a more concrete reference in the situation, such as "making startling remarks that attract attention", or "showing no irritation or anger even when justified". Statements such as these closely resemble the results of Buss & Craik's ( 1 983) act-nomination procedure. The emphasis in the present research on verbs represents an intermediate level of abstraction between the two just mentioned. Subsets of verbs, e.g., those comprised by the factors I and X may on the one hand represent the trait-level of description ( e.g., aggression), and may on the other hand refer to certain contexts. Verbs carry presuppositional aspects that refer to their use or their contextual relevance ( cf. Ballmer & Brennenstuhl 1981). Fillmore {1969) for example, paid attention to the presuppositional aspects of verbs of judging such as accuse, blame, and criticize. He attempted to describe the "role structure" of these verbs. The list obtained can be used to make explicit the purport ( illocutionary force) of the interpersonal activities, or the 'moves' in discourse-situations. In rating tasks judges have to indicate for each group of three verbs, to what extent the verbs together, in their common meaning, are applicable for describing the moves in question. The scores on the three individual scales of a factor should be summed in order to get more reliable measures. The empirical reason for using groups of verbs instead of single verbs to define the individual rating-scales was drawn from Kilkowsky (1976) and Hofstee et a!. (1981).These authors provided indications that, for personality judgments, ratings on groups of adjectives were more consistent than ratings on single adjectives. A theoretical argument is that the use of groups of terms prevents

234

Dept. for Personality PJychology and the Psychology ofPerJonallty UniverJityofGroningen GroteMarkt J/132, 9712 H V Groningen, The Netherlands

REFERENCES

1 980: An analysis of communicative action. I n M. Brenner (ed.) 1 980: The analysis of social situations. I n M . Brenner (ed.). Austin, J.L., 1 962: How to Do ThingJ With Words. Oxford University Press, Oxford. Ballmer, T., 1 983: Semantic structures of texts a n d discourses. Journal of Semantics 2:221 -252. Ballmer, T., 1 984: The position of argumentation i n the framework of a text linguistics, speech act theory, and lexicology. Journal of Pragmatics 8: 9-29. Ballmer, T. and Brennenstuhl, W., 1 98 1 : Speech A ct ClaJsification: A Study in the Lexical analysis of English Activity Verbs. Springer, Berlin. Benjamin, L.S., 1974: Structural analysis of social behavior. Psychological Review 8 1 : 392-425. Bochner, A.P., Kaminski, E.P., and Fitzpatrick, M . A ., 1 977: The conceptual domain of inter­ pe rsonal behavior: A factor-analytic study. Human Communication Research 3:291 -302. Bolinger, D., 1 980: Language - the Laaded Weapon: The Use and Abuse of Language Today. A l l wood, J ., A rgyle, M . ,

Longman, London.

(ed.), 1980: The Structure of A ction. Blackwell . Oxford. 1 945: A Grammar of Motives. Prentice-Hall. Englewood-Oiffs, N.J. Buss, D.M. and Craik, K . H ., 1 983: The act frequency approach to personality. Psychological Review 90: 105- 1 26. Buss, D. M . and Craik, K . H ., 1984: Acts, dispositions, and personality. I n B.A. Maher & W . B . Maher (eds.), ProgresJ in Experimental PerJonality Research, vol. 1 3. Academic Press, New

Brenner, M. Burke, K.,

York.

De Raad, B., 1 985: Person-talk in Everyday Life: Pragmatics of Utterancu about Personality. UnpubliShed doctoral dissenation, Groningen.

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judges from communicating stereotype meanings that are associated with single terms (cf. Bolinger 1980). The judges need not be qualified on their meta-linguistic awareness, since the verbs in question are selected for ordina­ ry language users. Moreover, experience shows that ordinary users have no problem with the meaning of the verbs. The most typical use for which the method of data-collecting was develo­ ped is in the area of act-sequences, involving an agent and an addressee.The participants can describe their actions according to the instruction above. If the sequences are restricted to two-tum interactions the agents-addressee contiguities can, for example, be studied by performing canonical correlation analysis (e.g. De Raad 1986). In cases of two or more turns the sequences can, for example, be analysed by studying the transition probabilities of one move to another, representing so-called Markov chains (e.g. Argyle 1980). Another possible use of the method can be in the personological area. Subjects can be asked to judge the frequency of actions of their own or of others in terms of the verbs. Examples are the fields of dispositional assessment (e.g. Buss & Craik 1 984) and interpersonal assessment (e.g. Wiggins 1980).

235 De Raad, B . , 1986: Pragmatics of utterances about personality: Everyday life scenarios.

Deventer. Hofstee, W . K . B . , Brokken, F.B. and Land, H . , 1 98 1 : Constructie van een standaard-persoon­ lijkheids-eigenschappen-hjst (SPEL). N�derlands Tijdschnft voor de Psychologi� 34: 443-452. Huttenlocher, J . , Smiley, P. and Charney, R . , 1 983: Emergence of action categories in the child: Evidence from verb meanings. Psychological Revi� 90: 72-93. Jessor, R . , 1 98 1 : The perceived environment in psychological theory and research. I n D. Magnusson (ed.). Jones, E. E . and Davis, K . E . , 1 965: From acts to dispositioas: The attribution process in person perception. In L . Berkowitz (ed.), Advances in Experim�ntal Sr;cial Psychology, vol. 2. Academic Press, New York. Kiesler, D. J. , 1 983: The 1 982 mterpersonal circle: A taxonomy for complementarity in human transactions. Psychological R�vt�w 90: 1 85-2 1 4. Kilkowsky, J . M . , 1 976: An �mpirica/ inv�stigation of the consist�ncy ofself-ratings Unpublished doctoral dissertation, University of Minnesota. Koenen, M.J. and Endepols, J., 1 966: V�rk/arend handwoordmboek der n�derlantbe taal. Wolters, Groningen. Kouwer, B.J . , 1973: Exisuntie/� psycho/ogi�: Gronds/agen van h�t psycho/ogisch� g�sprek. Boom, Meppel. Lehrer, A., 1 974: Semantic Fi�lds and Lextca/ Structur�. North-Holland, Amsterdam. Lorr, M. and McNair, D . M . , 1965: Expansion of the interpersonal behavior Circle. Journal of

Personality and Social Psychology 2: 823-830. Magnusson, D. (ed.), 198 1 : Toward a Psychology of Situations: An Jnuractionist P�rspective. N . J. Erlbaum, H illsdale. McHugh, P., 1 968: Defining the Situation: Th� Orgamzation of Meaning in Social Interaction. Bobbs-Merrill, New York. Messinger, H . , Sampson, H . and Towne, R . D . , 1 962: Life as theater: Some notes on the dramaturgical approach to social reality. Sociom�try 25: 98- 1 1 0. Miller, G . A . , 1 969: A psychological method to investigate verbal concepts. Journal of Math�­

matical Psychology 6: 1 69- 1 9 1 . Nowakowska, M . , 1 98 1 : Structure o f situation and action: Some remarks o n formal theory of action. In D . Magnusson (ed.). Osgood, C.E., 1970: I nterpersonal verbs and interpersonal behavior. I n J . L. Cowan (ed.),

Studi�s in Thought and Limguage. University of Arizona Press . Arizona.

Pearce, W . P . , 1 976: The coordinated management of meaning: A rules-based theory of inter­ personal communication. In G . R . Miller (ed.), Explorations in Interpersonal Communication. Sage, Beverly Hills, Calif. Price, R. H. and Bouffard, D.L., 1974: Behavioral appropriateness and situational constraint as di mensions of social behavior. Journal of Personality and Social Psychology 30: 5 1 9-586.

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In A. Angleitner, G . L . M . Van Heck, and A. Fumham (ed.s.), European Personality Psycho­ logy: R�cent Th�or�ttca/ and Empirical D�v�/opm�n/5 II. Swets and Zeitlinger, Lisse. Edmondson, W., 1 98 1 : Spok�n Discourse: A Mod�/ for Analysis. Longman, London. Fillmore, C.J., 1 969: Verbs of judg1ng: An exercise in semantic description. Pap�rs in Linguistics 1 : 9 1 - 1 1 7. Fiske, D . W . , 1 978: Straugt�s for Personality R�uarch: Th� Observation versus Jnurpretation of B�havior Jossey-Bass, San Francisco. Forgas, J . P . , 1 976: The perception of social episodes: Categorical and dimensional represen­ tations in two different social milieus. Journal of Personality and Social Psychology 34: 1 99-209. Goffman, E . , 1 976: Replies and responses. I.Anguag� tn Soci�ty 5: 257-3 1 3. Grimshaw, A . D . , 1 982: Comprehensive discourse analysis: An instance of p rofessional peer interaction. I.Anguag� in Society I I : 1 5-47. Harre, R. and Secord, P.F., 1 972: Th� Explanation of Social B�havior. Blackwell, Oxford. Helwig, P., l958: Dramaturgied�s m�nschlichen Lebens. Klett, Stuttgart. Hofstee, W . K . B . , 1 974: Psycho/ogisch� uitsprak�n over puson�n. Van Loghum Slaterus,

236 Rogers, L.E. and Farace, R . V. 1 975: Analysis of relational communication i n dyads: New measurement procedures. Human Communication R�s�arch I : 222-239. Rommetveit, R., 1 98 1 : On meanings of situation and social control of such meaning in human communication. In D . Magnusson (ed.). Scovel, T. S., 1 97 1 : A look-see at some verbs of perception. Languag� uarning 2 1 : 7 5-84. Searle, J.R., 1 975: A taxonomy of illocutionary acts. I n K. Gunderson (ed.), Languag�. Mind and

Knowl�dg�. University of Minnesota Press, Minneapolis. SjOberg, L., 1 981: Life situations and episodes as a basis for situational influence on action. In D. Magnusson (ed.). Stech, E . L . , 1 979: A grammar of conversation with a quantitative emp1rical test. Human

Communication R�s�arch 5: 1 58- 1 70. Tal my, L . , 1 975: Semantics and syntax of motion. In J.P. Kimball (ed.), Syntax and Semantics, Vol 4. Seminar Press, New York. Ten Berge, J . M .F., 1 977: Optimizing Factorial Invarianc�. Unpublished doctoral dissertation, University of Groningen. Watzlawick, P., Beavin, J . H . and Jackson, D .D . 1967: Pragmatics of Human Communication. Norton , New York. Wiggins, J.S., 1 979: A psychological taxonomy of trait-descriptive terms: The i nterpersonal domai n. Journal of Personality and Soctal Psychology 37: 395-4 1 2. Wiggins, J. S., 1 980: Circumplex models of interpersonal behavior. In L. Wheeler (ed.), Review of

�rsonality and social psychology Vol I. Sage, Beverly Hills, Calif.

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Verschueren, J., 1 98 1 : Problems of lexical semantics. Lingua 53: 3 1 7-35 1 .

Jour/Ul/ of St!mantics

4: 237-246

COMMON SENSE INFERENCE IN A FOCUS-GUIDED ANAPHOR RESOLVER DAVID M . CARTER

ABSTRACT

and local focussing as heavily as possible; it does not rely on the presence of large amounts of world or domain knowledge, which are notoriously hard to process accurately. The ideas reported are implemented in a program called SPAR (Shallow Processing Anaphor Resolver), which resolves a naphoric ambiguities in simple English stories and generates senten­ ce-by-sentence paraphrases that show what interpretations have been selected. To resolve anaphors, SPAR combines and develops several existmg techniques, most notably Sidner's theory of local focussing and Wilks' 'preference semantics' theory of semantics and common sense inference. Consideration of the need to resolve several anaphors in the same sentence results in Sidner's framework being modified and extended to allow focus-based processing to interact more flexibly with processing based on other types of knowledge. Wilks' treatment of common sense inference

is extended to incorporate a Wider range of types of mference without jeopardizing its

uniformity and simplicity. In the absence o f large quantities of world knowledge, successful anaphor resolution is seen to depend on the coordination of predictions made by system components exploiting various knowledge sources. Such coordination normally allows ana­ phors to be resolved correctly even when no single source of predictions

is sufficient on its own.

I . A SHALLOW PROCESSING HYPOTHESIS

A computer system that resolves anaphors in non-specialised texts such as stories must be able to take account of many different kinds of knowledge. Some of the most important are: syntactic knowledge about agreement and configurational constraints on coreference; semantic knowledge, especially of word meanings; local and global focussing; and common sense knowledge of the world. Of these, the last is by far the hardest to represent and apply, because of its complexity, diversity and quantity. Present-day systems capa­ ble of text understanding can therefore normally only cope with a rather limited range of texts: limited in domain, and/or in the type of reasoning required. However, it seems plausible that a considerately written text ( i.e. one that is perspicuous and unambiguous, in accordance with Grice's maxim of man­ ner) will normally be constructed in such a way that constraints on interpreta­ tion derived from different kinds of knowledge will tend not to conflict but

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This paper describes an investigation of the feasibility of resolving anaphors in natural language texts by means of a 'shallow processing' approach which exploits knowledge of syntax, semantics

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A story processing system which exploits linguistic knowledge, particularly knowledge about local focussing, as heavily as possible, and has access only to limited quantities of world knowledge, which it invokes only when absolutely necessary, can usually choose an ap­ propriate antecedent for an anaph or even in cases where the common sense inference mechanism by itself cannot do so. This paper deals with the problems of coordinating the application of syntax , word sense semantics, and especially local focussing and world knowledge, in a shallow processing anaphor resolver. Such coordination turns out to be crucial to accurate performance. The approach adopted is a synthesis of Sidner's (1979) work on local focus and Wilks' ( l975a, l 975b, 1977) prefer­ ence semantics, both of which will now be reviewed.

2. BACKGROUND

In Sidner's theory, pronoun interpretation ( PI) rules are applied to each pronoun in a sentence independently of the others. The rules suggest candi­ date antecedents, normally one at a time, according to the contents of a set of focus registers which have been set during processing of earlier sentences. If a candidate agrees syntactically with the pronoun, it is temporarily bound to it, and inference is invoked using semantic and common sense knowledge. In Sidner's words, "the complexity of the inferencing is constrained to asking for confirmation of the sentence predication, thereby eliminating combina­ torial search for antecedents and non-terminating inferencing." ( Sidner 1979:75). This confirmation consists of "proving that the sentence with the pronoun replaced by the cospecified noun phrase is consistent with other knowledge." (p. 150). In other words, as long as the suggested candidate does not give rise to a contradiction, it is accepted. Sometimes, however, the rules suggest two or more candidates at once.

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rather to confirm one another and work together to guide the reader towards correct interpretations. Moreover, because language has some degree of redundancy, the same information may often be contained in more than one constraint or prediction. For example, when resolving a pronoun, we might expect that the most focussed possible referent will usually also be the one that common sense reasoning suggests is most plausible. If so, it may be possible to resolve most instances of at least some kinds of ambiguity by adopting a 'shallow processing' approach in which linguistic knowledge ( syntactic, semantic and focussing) is exploited as fully as possi­ ble, while world knowledge is present only in very limited quantities and is exploited, by common sense inference ( CS I), only when linguistic knowledge alone is insufficient to resolve an ambiguity. Specifically, this research sets out to test the following Shallow Processing Hypothesis:

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3. COORDINATED A N A PHOR RESOLUTION: THE SPAR SYSTEM

My S PA R ( Shallow Processing Anaphor Resolver) system ( Carter 1984, 1 985) is a Sidnerian anaphor resolver which uses Wilksian semantics and CSI to do the work of Sidner's 'normal mode' and 'special mode' inference respectively. It is applied to initial sentence interpretations produced by Boguraev's (1979) English analyser, a system that employs syntactic knowl­ edge encoded as an augmented transition network and a modified form of Wilksian semantics. This analyser resolves most word sense and structural ambiguities (producing alternative interpretations if any are unresolvable in

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When this happens, inference is invoked in a different mode to decide which candidate ( if any) is most plausible. Although Sidner viewed this mode of inference as 'special', it is in practice required quite often. Full noun phrase anaphors are also resolved using focus-based rules, which however only require 'normal mode' (single-candidate) inference and not 'special mode' . Sidner did not detail the functioning ofeither mode of the inference mechanism, although she viewed doing so as "an important aspect of ongoing research in artificial intelligence" (p. 1 50), and gave a number of examples of what the mechanism should be capable of. Sidner's theory is incomplete in two important respects. Firstly, the PI rules do not specify how or when candidates from the same sentence as the pronoun should be considered. Secondly, no attention is given to any possi­ ble interaction between the applications of the rules to different anaphors in a sentence. Both problems need to be tackled in a practical system. In Wilks' preference semantics theory, focussing was assigned a very minor role. Instead, common sense inference ( CSI) rules were invoked whenever a pronoun could not be resolved by semantic pattern matching alone. Each rule expressed a ( usually causal) relationship in terms of two linked semantic patterns consisting of general semantic primitives. They were used to construct (hopefully consistent) chains connecting the representation of a sentence containing problem pronouns with those of sentences containing candidate antecedents. A completed chain would bind one or more pro­ nouns. Thus in Wilks' framework, semantic matching was used to assess the plausibility of single candidates and therefore roughly corresponded to Sid­ ner's proposed 'normal mode' of inference. CSI, on the other hand, was used to select one candidate out of many for each problem pronoun, as in Sidner's 'special mode' of inference. Wilks' semantics and CSI mechanisms, although more modest in their aims than those Sidner assumed, were specified in . enough detail to allow implementation to be begun. They thus provide a way to get an implementation for non-specialised texts of Sidner's theory off the ground; and they are sufficiently simple, flexible and general to be a suitable basis for a shallow processing system.

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the absenceofextrasententialcontext)butdoesnottackleanaphoricambiguity. The interpretations produced arerelativelyshallowcase-organiseddependency structures with word senses defined by Wilksian 'formulas', trees constructed from a set of a hundred of so semantic primitives. SPA R resolves the anaphors in the dependency structures, in the process resolving any remaining word sense and structural ambiguity. When each sentence has been fully processed, a paraphrase is produced which makes clear what ambiguity resolution decisions have been made. The system acts on the dependency structure( s) for a sentence in a story as follows. In preparation for PI rule application, the semantic formula for each word sense in a dependency structure is matched with the surrounding parts of the structure. This provides a measure of 'semantic density' ( strong agreement is a ground for preferring that reading over others) and also constraints the semantic ranges of pronouns. For example, the formula for drink specifies a liquid object, so in the sentence He drank it, it would be restricted to match only a liquid antecedent. Next, PI rules are applied to each pronoun in a sentence; other focus-based rules are applied to full noun phrase anaphors. Applications to different anaphors are independent except where one anaphor is a constituent of another. Although the PI and full N P rules themselves closely resemble Sidner's, there are important differences in the way they are applied. These differences are a consequence partly of adopting a shallow processing ap­ proach and partly of extending Sidner's theory to consider intrasentential candidate antecedents and interactions between different anaphors in the same sentence. In the PI rule application, if there is only a single candidate antecedent suggested by the PI rules, it is first matched with the pronoun, using their Wilksian semantic formulas and any restrictions imposed in the first stage of processing.This matching corresponds roughly to invoking Sidner's 'normal mode' inference, since most contradictions resulting from temporary bind­ ings take the form of semantic clashes. If the match succeeds, a firm 'predic­ tion' that the pronoun and candidate corefer is returned by the PI rules and put aside until later. Otherwise the rules go on to suggest further candidates. If, instead of a single candidate, the PI rules suggest several candidates at once, each one is matched semantically with the pronoun. If several survive, CSI is not invoked immediately, as in Sidner's original framework; rather, alternative predictions are returned, to be adjudicated later. CSI is postponed for two reasons. Firstly, as we will see below, it is often possible, by compa­ ring predictions for different anaphors, to avoid CSI altogether; and second­ ly, because an inference chain often binds several anaphors at a time. It is therefore both simpler and more efficient to invoke CSI for all unresolved anaphors in a sentence together than for each one as it arises. Consideration of intrasentential candidate antecedents is not achieved in the obvious way by inserting extra PI rules, because the rules are already rather complex and because there seem in any case to be very few reliable

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(i)

I took my dog to the vet on Friday. He bit him in the hand.

(trivially altered from Sidner ( 1979)), the PI rules aided by the semantic matcher, predict that he could be either the dog or the vet, while him can only be the vet (since hand is defined as part of a person, not of a dog). The MGC constraint prevents he and him coreferring; SPAR therefore reasons that since him must be the vet, he cannot be. Thus by not invoking CSI early on when the PI rules suggested two plausible candidates for he, we have managed to avoid CSI altogether. If configurational constraints detect a clash between two firm predictions (i.e. predictions without alternatives), the PI rules are re-applied to the anaphors involved in order to find further plausible candidates. In practice, this is very seldom necessary. CSI is only invoked if some anaphors remain unresolved even after confi­ gurational constraints have been applied. As Sidner recommended, the pre­ dictions of the PI rules for those anaphors are used to constrain both the starting points for inference and the directions in which it proceeds. We are only interested in inference chains which bind anaphors to candidates predicted by the PI rules; other chains represent a clash between focussing and CSI, and when this occurs, the CSI prediction is rejected. If Sidner's theory is correct, this would be the correct course of action even if the CSI mechanism were a powerful one; the fact that it is not makes the focus prediction even more obviously preferable. If the PI rules, configurational constraints and CSI between them finally resolve all anaphors, no more need be done. However, because the CSI mechanism has only limited amounts of knowledge available, it will often not find all the chains that a more powerful mechanism might construct, and so some anaphors may remain unresolved. In such cases, up to three weaker heuristics are applied which, although there are many counterexamples,

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preferences statable in focussing terms either between intrasentential candi­ dates or between intrasentential and contextual candidates. Instead, before the PI rules are applied to each pronoun, the focus registers are temporarily augmented with intrasentential candidates, ordered approximately as speci­ fied by Hobbs' (1976) syntactic algorith m 1 ; the PI rules then pick them up j ust as they do contextual candidates. An important consequence of this is that fewer of the PI rules' suggestions consist of a single candidate; it becomes more common for several candidates to be suggested together. However, as stated above, CSI (i.e. 'special mode' inference) is not invoked immediately when this happens. When the PI rules have been applied to each anaphor in the sentence, configurational constraints (specifically, approximations to Reinhart's (1983) c-