Cognition, Vol. 2, No. 2

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Non-linguistic

strategies and the acquisition of word meanings*

EVE ‘J. CLARK Stanford University

Abstract The present study proposes that children’s apparent comprehension of certain words is atjrst dependent on a combination of their linguistic hypotheses about a word’s meaning and certain non-linguistic strategies. Children aged 1;6-5;O were given instructions requiring comprehension of the locative terms in, on and under. The results showed that children go through three stages: At first, they consistently use certain non-linguistic strategies that can be characterized by two ordered rules; next, they apply these rules to only one or two of the locative instructions; and$nally, they exhibit full semantic knowledge of the three word meanings. Because of these non-linguistic strategies, the younger children always appear to understand in correctly, sometimes appear to understand on and never understand under. It is argued, nevertheless, that these non-linguistic strategies determine the order of acquisition of the three locative terms. Recent work on the acquisition of word meanings suggests that children begin by using certain non-linguistic strategies based on their perceptual knowledge. Indeed, they have obvious recourse to perceptual information in the numerous over-extensions that have been observed during the first year or so of language use (between about 1; 0 and 2; 6). For example, the earliest meaning ascribed to a word like apple is often something like ‘[SMALL X] & [ROUND Xl’. The child’s interpretations of these percept-based features, size and shape, are then used criterially in applying the word * This research was supported in part by the National Science Foundation, GS-30040. Deborah Rosenblatt assisted in running the first two experiments, and Carol B. Farwell helped with Experiment 3. I am grateful to the stat7 of Bing Nursery School, the Stanford Child Care Center and the parents of the children for all their cooperation. I would like

to thank Herbert H. Clark for making detailed comments on the manuscript at various stages, and lastly I wish to acknowledge an anonymous reviewer whose remarks substantially improved this paper. Requests for reprints should be sent to the author at Committee on Linguistics, Stanford University, Stanford, California 94305, U.S.A. Cognition Z(2), pp. 161-182

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apple to other

objects such as door-knobs, rubber balls, round light switches and paperweights. These over-extensions, characteristically based on features of shape, size, movement, sound, texture and taste, are well documented in diary studies of the acquisition of a large number of different languages (E. Clark, 1973b). These over-extensions might be best explained as the outcome of the young child’s hypotheses about word meaning. His hypotheses would seem to take the general form of ‘A word refers to some identifiable [perceptual] attribute of the object pointed to’. Thus, the child is relying on the perceptual knowledge that he already has of the things around him when he begins to form hypotheses about the meanings of new words. These linguistic hypotheses then lead him to act on the assumption that the feature or attribute he has picked out is what that particular word designates. Therefore, any other object that matches those features can be ‘named’ by the same word (E. Clark, 1974). It is therefore the child’s interpretations of his percepts, his knowledge about the properties of objects, that provide a basis for some linguistic hypotheses for assigning meaning to ‘new’ words. Children, however, also show certain biases in their treatment of the world around them that bear no direct relation to their linguistic hypotheses. For example, if a young child is shown a piece of chocolate and a pebble and is allowed to choose one, he will probably always choose the chocolate. This choice would then be independent of the meanings of words used in the instructions to choose; his choice is the outcome of a non-linguistic strategy. This form of behavior is traditionally referred to as a preference or a response bias and may be present in the child (or the adult) for a variety of reasons. If the child relies consistently on such preferences, though, it is important to identify them. This is because they could make it appear that the child had understood something when, in fact, his response was simply due to a nonlinguistic strategy. This question is a particularly important one where children’s comprehension of word meanings is concerned. The child might appear to have grasped the adult meaning of some complex word when he was actually only responding on the basis of a non-linguistic strategy. There are therefore two ways of looking at many comprehension studies. First of all, the child’s responses, including his errors, could be treated as if they were the outcome of his linguistic hypotheses about the meanings of particular words. Secondly, the child’s responses could be regarded as the outcome of some non-linguistic strategy. However, these two approaches are often impossible to separate. For example, there have been several studies of the relational terms more and less in which children appeared to interpret the word less as if it meant more. For instance, whenever children were asked to choose from two trees either the one with more apples or the one with less, they always chose the one with the greater number (Donaldson and Balfour, 1968; Donaldson and Wales, 1970; Palermo, 1973). There are two possible explana-

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tions that might be offered for these data, explanations that have not been clearly distinguished in the discussions of what less actually means to the child. The first explanation assumes that the child is relying on his linguistic hypothesis about the meanings of more and less, namely that both words refer to amount or quantity [ +Amount], and to the positive pole, i.e., the greater of two or more amounts [ +Polar]. This is the correct meaning for more, but not for less. This analysis will be called the full semantics hypothesis. An alternative explanation for the same data makes a weaker assumption about the child’s meanings for the two words. Instead of assuming that more and less are synonymous, both with the meaning of more, one could suppose that both word meanings are actually incomplete and that the child’s responses are based on the partial meaning that he has for both more and less, in combination with certain nonlinguistic strategies. Thus, the child might know only that both more and less refer to amount [+Amount]. This tends to be supported by the children who, when asked to show which tree had more apples on it, replied Both of them, That one does an’ that one, Both the trees, They two ones, Each tree, and so on. Other children, asked to make the amount less on one tree (the one with more) objected: But it is less on that tree (Donaldson and Wales, 1970, p. 248). In addition to this partial semantic knowledge, the child at this stage would be assumed to have a non-linguistic strategy of usually choosing the greater of two or more amounts or the more extended object on a dimension such as length or height. H. Clark (1970) appealed implicitly to such a notion in suggesting that the first stage in the acquisition of more and less involves only a nominal sense of the words, i.e., both words refer only to amount, and that one had to assume that the best exemplars of amount for the young child are those objects with greater amount. This assumption has since been tested experimentally by Klatzky, Clark and Macken (1973). They showed that children found it significantly easier to learn the meanings of nonsense syllables that referred to relatively greater extent along several dimensions than to learn their polar opposites. Thus, in the case of more and less, the child would know that both words meant [+Amount], but would not yet have learnt the feature [&Polar]. It only appears that he has [t-Polar as well as [+Amount] because of the strategy of choosing the greater amount. This explanation, based on the combination of partial semantic knowledge and a nonlinguistic strategy, will be called the partial semantics hypothesis. The full semantics hypothesis and the partial semantics hypothesis should be distinguishable if one could find a situation in which the child treated WORD, as if it meant the same as WORD2 in some contexts, while at the same time treating WORD1 as if it meant WORD, in another set of contexts. One would thus be able to demonstrate that the two incompatible senses consistently given to WORD1 were not random but, in fact, could be ascribed to the child’s use of certain non-linguistic

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strategies. This has not actually been shown in the case of more and less, although it has been shown, in effect, by the over-extended uses of early words like apple (E. Clark, 1973b). If the child’s responses to any particular words can be shown to be the outcome of a little semantic knowledge (if that) combined with certain non-linguistic strategies, then it would be clear that the full semantics hypothesis would make too strong a claim about the extent of the child’s semantic knowledge. The partial semantics hypothesis, in contrast, is concerned with precisely that interaction, the way in which the child relies on non-linguistic strategies prior to, and during, the acquisition of word meanings. These two hypotheses are not true or false in general, but they may be contrasted for any particular word or set of words. In the present paper, I shall present some comprehension studies of locative prepositions in an attempt to explore one set of strategies and their relationship to the young child’s semantic knowledge. During the acquisition of the terms in, on and under, children appear to treat the word under as if it means in in some contexts, but as if it means OIZin others. This suggests that this is a case where the partial semantics hypothesis, with its non-linguistic strategies, might provide a better account of the data than an explanation based on the full semantics hypothesis.

Experiment

1

Method Each child was asked to follow instructions containing the words in, on and under in contexts that allowed both correct and incorrect responses. The instructions were of the form Put the x in [on, under] the y, where x was one of eight small toy animals, and y one of six reference point objects (henceforth RPs). The child’s task was to correctly locate one object, X, with respect to the RP, y.l The six RPs, shown in Figure 1, were chosen because each allowed two of the three spatial relations being named in the instructions. Thus, the box on its side and the tunnel each allowed an object to be placed either in or on the RP. The dump truck and the crib each allowed either in or under, and the table and the bridge each allowed either on or under. There were 24 instructions in all, with eight for each of the three prepositions in, on and under. Each preposition occurred twice with each of the four RPs that allowed 1. The children in these experiments always picked up X, rather than y, and then placed it in relation to y. Thus, the RPs were always treated as reference points. Other research has shown that young children find it impossible to

place B when told ‘A is on top of B’; they can always do the task, though, if told to place A (Bern, 1970; Huttenlocher, Eisenberg and Strauss, 1968; Huttenlocher and Strauss, 1968).

Non-linguistic

Figure

1.

strategies

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The reference point objects (RPs) used in Experiment I: Items I and 2 allow the relations IN and ON; items 3 and 4 allow the relations IN and UNDER; items 5 and 6 allow the relations ON and UNDER

the relation, e.g., in occurred twice each with the box, the tunnel, the truck and the crib. The names of the eight animals each occurred three times in all, once each with each preposition. The instructions were divided into two identical blocks of 12, and the order of instructions within each block was randomized separately for each subject. The subjects were 70 children (31 male and 39 female) taking part in a larger study of the acquisition of spatial terms in English. All the children were native speakers of English and had no contact with other languages in the home. The older children (2; 6-5;O) were attending Bing Nursery School, Stanford; the younger ones (I ; 6-2; 5) were contacted through Bing Nursery School and the Stanford Child Care Center. The children were divided into seven age-groups at six-monthly intervals, with ten childrenin each group: 1. 1;6-I;11 (mean age 1;9); II. 2;0-2;5 (mean 2;3); III. 2;62;ll (mean 2;9); IV. 3;0-3;5 (mean 3;3); V. 3;6-3;ll (mean 3;9); VI. 4;0-4;5 (mean 4;2); VII. 4;6-4; 11 (mean 4;8). Each subject was interviewed separately in a small experimental room at the nursery school. (Five subjects from Group II were seen under comparable circumstances at the child care center.) The children in the two youngest groups (aged 1;6-2; 5) generally had one parent present throughout, seated slightly behind the child and out of his line of sight. The parent made no comments during the experimental trials. Each child was first asked to name each of the RPs and the animals. The child’s own names for the objects were used throughout the session wherever these differed from the ones originally assigned. Then the experimenter gave the child the two blocks of

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12 instructions each. Some of the younger subjects had a short break between the two blocks; all completed the task, with no responses omitted, in a single session that lasted between ten and 20 minutes.

Results

The data will be analyzed first in terms of how the children carried out the instructions they were given where a correct response is a response that appears to reflect adultlike knowledge of the word meaning in question. Following this, the kind of errors made will be used as the basis for analyzing the data in terms of possible non-linguistic strategies where a ‘correct’ response is defined as consistent, predictable use of a particular strategy. For the first analysis, the percentage of correct responses to each instruction is shown for all seven age groups in Table 1. Because of the low error rate and absence of any significant differences between age groups for subjects over 3 ;O years (Groups IV-VII), an analysis of variance was performed only on the data from the three youngest groups. These three groups differed from each other significantly overall, F (2,27)= 16.00, p < 0.001. The interaction between age groups and instructions, F (4,54)= 12.66, p