Linda B. Smith

The importance of shape in early lexical learning

Abstract We ask if certain dimensions of perceptual similarity are weighted more heavily than others in determining word extension. The specific dimensions examined were shape, size, and texture. In four experiments, subjects were asked either to extend a novel count noun to new instances or, in a nonword classification task, to put together objects that go together. The subjects were 2-year-olds, 3-year-olds, and adults. The results of all four experiments indicate that 2- and 3-year-olds and adults all weight shape more heavily than they do size or texture. This observed emphasis on shape, however, depends on the age of the subject and the task. First, there is a developmental trend. The shape bias increases in strength and generality from 2 to 3 years of age and more markedly from early childhood to adulthood. Second, in young children, the shape bias is much stronger in word extension than in nonword classification tasks. These results suggest that the development of the shape bias originates in language learning—it reflects a fact about language—and does not stem from general perceptual processes.

Development as a dynamic system.

Development is about creating something more from something less, for example, a walking and talking toddler from a helpless infant. One current theoretical framework views the developmental process as a change within a complex dynamic system. Development is seen as the emergent product of many decentralized and local interactions that occur in real time. We examine how studying the multicausality of real-time processes could be the key to understanding change over developmental time. We specifically consider recent research and theory on perseverative reaching by infants as a case study that demonstrates this approach.

Object name Learning Provides On-the-Job Training for Attention

By the age of 3, children easily learn to name new objects, extending new names for unfamiliar objects by similarity in shape. Two experiments tested the proposal that experience in learning object names tunes childrens attention to the properties relevant for naming—in the present case, to the property of shape—and thus facilitates the learning of more object names. In Experiment 1, a 9-week longitudinal study, 17-month-old children who repeatedly played with and heard names for members of unfamiliar object categories well organized by shape formed the generalization that only objects with similar shapes have the same name. Trained children also showed a dramatic increase in acquisition of new object names outside of the laboratory during the course of the study. Experiment 2 replicated these findings and showed that they depended on childrens learning both a coherent category structure and object names. Thus, children who learn specific names for specific things in categories with a common organizing property—in this case, shape—also learn to attend to just the right property—in this case, shape—for learning more object names.

Rapid Word Learning Under Uncertainty via Cross-Situational Statistics

There are an infinite number of possible word-to-word pairings in naturalistic learning environments. Previous proposals to solve this mapping problem have focused on linguistic, social, representational, and attentional constraints at a single moment. This article discusses a cross-situational learning strategy based on computing distributional statistics across words, across referents, and, most important, across the co-occurrences of words and referents at multiple moments. We briefly exposed adults to a set of trials that each contained multiple spoken words and multiple pictures of individual objects; no information about word-picture correspondences was given within a trial. Nonetheless, over trials, subjects learned the word-picture mappings through cross-trial statistical relations. Different learning conditions varied the degree of within-trial reference uncertainty, the number of trials, and the length of trials. Overall, the remarkable performance of learners in various learning conditions suggests that they calculate cross-trial statistics with sufficient fidelity and by doing so rapidly learn word-referent pairs even in highly ambiguous learning contexts.

The place of perception in children's concepts ☆

Current research on childrens concepts and categories reflects a growing consensus that nonperceptual knowledge is central to concepts and determines category membership, whereas perceptual knowledge is peripheral in concepts and at best a rough guide to category membership. In this article, we assess the theoretical and empirical bases for this view. We examine experiments that seem to support the idea that concepts are principally nonperceptual, and find that the evidence is not compelling. We then turn to research on childrens lexical category formation, which highlights multidirectional interactions between perception, language, and other kinds of knowledge, in specific contexts. This evidence suggests that conceptual knowledge encompasses both perceptual and nonperceptual knowledge as equal and interacting partners. The evidence also suggests a view of concepts, not as mentally represented structures, but as assemblies of knowledge computed on-line in specific task contexts. A view of concepts as primarily nonperceptual is gaining ground. This view is influencing the kinds of experiments being done, and perhaps more importantly, the kinds of experiments not being done. In this article, we argue that there is no compelling basis either in theory or in data for the idea that concepts are principally, centrally, or most importantly nonperceptual. We begin by presenting a composite description of concept structure derived from the proposals of a number of researchers. Although this view may not be held in its precise form by any single theorist, we believe it accurately captures

Early noun vocabularies: do ontology, category structure and syntax correspond?

This paper examines childrens early noun vocabularies and their interpretations of names for solid and non-solid things. Previous research in this area assumes that ontology, category organization and syntax correspond in the nouns children learn early such that categories of solid things are organized by shape similarity and named with count nouns and categories of non-solid things are organized by material similarity and named with mass nouns. In Experiment 1 we examine the validity of this assumption in a corpus of early-learned nouns and conclude that one side of the solidity-syntax-category organization mapping is favored. In our second experiment we examine the relation between early noun vocabulary development and novel word generalization. We find that children between 17 and 33 months of age do not systematically generalize names for solid things by shape similarity until they already know many nouns, and do not systematically generalize names for non-solid substances by material similarity. The implications for childrens acquisition of the ontological distinction, count/mass syntax, and novel nouns are discussed.

The Development of Embodied Cognition: Six Lessons from Babies

The embodiment hypothesis is the idea that intelligence emerges in the interaction of an agent with an environment and as a result of sensorimotor activity. We offer six lessons for developing embodied intelligent agents suggested by research in developmental psychology. We argue that starting as a baby grounded in a physical, social, and linguistic world is crucial to the development of the flexible and inventive intelligence that characterizes humankind.

Letting structure emerge: connectionist and dynamical systems approaches to cognition

Connectionist and dynamical systems approaches explain human thought, language and behavior in terms of the emergent consequences of a large number of simple noncognitive processes. We view the entities that serve as the basis for structured probabilistic approaches as abstractions that are occasionally useful but often misleading: they have no real basis in the actual processes that give rise to linguistic and cognitive abilities or to the development of these abilities. Although structured probabilistic approaches can be useful in determining what would be optimal under certain assumptions, we propose that connectionist, dynamical systems, and related approaches, which focus on explaining the mechanisms that give rise to cognition, will be essential in achieving a full understanding of cognition and development.

From the lexicon to expectations about kinds: A role for associative learning

In the novel noun generalization task, 2 1/2-year-old children display generalized expectations about how solid and nonsolid things are named, extending names for never-before-encountered solids by shape and for never-before-encountered nonsolids by material. This distinction between solids and nonsolids has been interpreted in terms of an ontological distinction between objects and substances. Nine simulations and behavioral experiments tested the hypothesis that these expectations arise from the correlations characterizing early learned noun categories. In the simulation studies, connectionist networks were trained on noun vocabularies modeled after those of children. These networks formed generalized expectations about solids and nonsolids that match childrens performances in the novel noun generalization task in the very different languages of English and Japanese. The simulations also generate new predictions supported by new experiments with children. Implications are discussed in terms of childrens development of distinctions between kinds of categories and in terms of the nature of this knowledge.

Count Nouns, Adjectives, and Perceptual Properties in Children's Novel Word Interpretations

Three-year-old children were shown a novel exemplar toy and asked to judge test items that differed from the exemplar in shape, coloration, or material substance. In the count noun condition, children judged whether test items had the same novel name as the exemplar. In the adjective condition, children judged whether a test hern could be described by the same novel adjective as the exemplar. The results of 3 experiments indicated that children systematically attend to shape in interpreting novel count nouns, but their interpretation of adjectives is contextually determined. By the age of 6, children have acquired roughly 14,000 words (Templin, 1957). How do they acquire so many words so fast? If one views the childs acquisition of word-referent relations as an instance of unbiased hypothesis testing, then the rate of early word acquisition is difficult to explain. As Quine (1960) pointed out, the use of a word in the context of some scene provides evidence consistent with many hypotheses, only one of which will usually be correct. Chomsky (1986) similarly argued that if language learners were free to form any possible hypotheses about intended meaning from spoken language, then it would be unlikely that they would learn language as rapidly as they do because it would be unlikely that they would test the correct hypotheses early in language learning by happenstance alone. Chomsky argued that the rapid and error-free language learning that we observe in children requires that children be biased to entertain some hypotheses more than others. This idea has motivated much research on childrens early word learning. Developmentalists have shown that childrens novel word extensions are constrained or biased in certain directions. For example, young children appear biased to interpret count nouns as referring to object categories and not individual objects (Katz, Baker, & MacNamara, 1974) or thematic relations between objects (Markman & Hutchinson, 1984; Waxman & Kosowski, 1990). Children are biased to allow only one label for a single referent (mutual exclusivity, e.g., Markman, 1989; Markman & Wachtel, 1988), and they are biased to attend to shape when extending a novel count noun across novel objects (Landau, Smith, & Jones, 1988). The existence of these biases is sometimes cited as an explanation of rapid word growth; the idea is that word learning proceeds as fast as it does precisely because word learning biases exist.