Abstract not found

It is often asserted that young children’s word learning is guided by constraints or internal biases. Constraints are broadly described as ‘‘any factor that favors some possibilities over others’ ’ (Medin et al., 1990). Researchers have argued that specialized lexical constraints cause children to make some inferences about word meanings before others. An analysis shows that the concept constraint is not informative because it does not differentiate a circumscribed set of word learning behaviors. Defining constraints as innate and domain-specific does not remedy this problem. We cannot separate the effects of so-called constraints or biases from a wide range of cognitive and contextual influences on children’s inferences about novel word meanings. This conclusion is supported by a selective review of these influences. The summary highlights our need for an explanatory framework that is sufficiently rich to capture the flexibility and diversity of children’s word learning. The core of such a framework is summarized as a set of general characteristics of human word learning. These characteristics must serve as a starting point for any viable theory of word learning. Prescriptions for future development of a viable framework are suggested. © 2000 Academic Press Word learning 1 is a complex and intractable problem for which researchers have offered a seemingly simple and powerful solution. The problem is that preschoolers ’ prolific acquisition of new words (averaging a half dozen per day; Carey, 1978) seems impossible given the radical indeterminacy of word meanings. A novel word has an indefinite number of possible meanings, and it is unlikely that children regularly receive information that unambiguously specifies a single meaning. Yet children often infer new words ’ correct or Preparation of the manuscript was supported by a postdoctoral fellowship from the Spencer

The authors asked whether there is evidence to support the existence of the vocabulary spurt, an increase in the rate of word learning that is thought to occur during the 2nd year of life. Using longitudinal data from 38 children, they modeled the rate of word learning with two functions, one with an inflection point (logistic), which would indicate a spurt, and one without an inflection point (quadratic). Comparing the fits of these two functions using likelihood ratios, they found that just 5 children had a better logistic fit, which indicated that these children underwent a spurt. The implications for theories of cognitive and language development are considered. Typically developing children utter their first words between 8 and 14 months of age. At this time, they add words to their repertoire at a slow rate. As they get older and their vocabulary increases, their rate of learning new words also increases—it has to if they are to reach an average vocabulary level of 300 words by 24 months (Fenson, Dale, Reznick, Bates, & Thal, 1994) and 60,000 words by 18 years (Aitchinson, 1994). In addition, it is widely held that children’s rate of vocabulary acquisition does not simply increase but undergoes a discrete transition at approximately 50 words. At this time, children putatively switch from an initial stage of slow vocabulary growth to a subsequent stage of faster growth. This transition has been referred to as the vocabulary spurt, the vocabulary burst, or the naming explosion (L.

Cognitive science is, more than anything else, a pursuit of cognitive mechanisms. To make headway towards a mechanistic account of any particular cognitive phenomenon, a researcher must choose among the many architectures available to guide and constrain the account. It is thus fitting that this volume on contemporary debates in cognitive science includes two issues of architecture, each articulated in the 1980s but still unresolved: • Just how modular is the mind? (section 1) – a debate initially pitting encapsulated mechanisms (Fodorian modules that feed their ultimate outputs to a nonmodular central cognition) against highly interactive ones (e.g., connectionist networks that continuously feed streams of output to one another). • Does the mind process language-like representations according to formal rules? (this section) – a debate initially pitting symbolic architectures (such as Chomsky’s generative grammar or Fodor’s language of thought) against less language-like architectures (such as connectionist or dynamical ones). Our project here is to consider the second issue within the broader context of where cognitive science has been and where it is headed. The notion that cognition in general—not just language

Words, kinds and causal powers: A theory theory perspective on early naming and categorization. For some twenty-five years, the prevailing theories of categorization in philosophy have invoked the idea of “kinds ” (Putnam, 1975; Kripke, 1972). When we look at how adults use words to refer to categories of things we find that they only rarely categorize objects on the basis of their common properties. Instead, adults seem to categorize objects together when they believe that they belong to the same “kind”; that is, that they share some common, abstract “essence.” Psychological investigations of adults have largely confirmed these philosophical intuitions, adults do seem to group objects together based on “kinds ” rather than properties (Murphy &

Developmental trajectories provide the empirical foundation for theories about change processes during development. However, the ability to distinguish among alternative trajectories depends on how frequently observations are sampled. This study used real behavioral data, with real patterns of variability, to examine the effects of sampling at different intervals on characterization of the underlying trajectory. Data were derived from a set of 32 infant motor skills indexed daily during the first 18 months. Larger sampling intervals (2–31 days) were simulated by systematically removing observations from the daily data and interpolating over the gaps. Infrequent sampling caused decreasing sensitivity to fluctuations in the daily data: Variable trajectories erroneously appeared as step functions, and estimates of onset ages were increasingly off target. Sensitivity to variation decreased as an inverse power function of sampling interval, resulting in severe degradation of the trajectory with intervals longer than 7 days. These findings suggest that sampling rates typically used by developmental researchers may be inadequate to accurately depict patterns of variability and the shape of developmental change. Inadequate sampling regimes therefore may seriously compromise theories of development.

Previous studies indicate that English-learning children acquire the distinction between singular and plural nouns between 22 and 24 months of age. Also, their use of the distinction is correlated with the capacity to distinguish nonlinguistically between singular and plural sets in a manual search paradigm (D. Barner, D. Thalwitz, J. Wood, S. Yang, & S. Carey, 2007). The authors used 3 experiments to explore the causal relation between these 2 capacities. Relative to English, Japanese and Mandarin had impoverished singular–plural marking. Using the manual search task, in Experiment 1 the authors found that by around 22 months of age, Japanese children also distinguished between singular and plural sets. Experiments 2 and 3 extended this finding to Mandarin-learning toddlers. Mandarin learners who were 20–24 months of age did not yet comprehend Mandarin singular–plural marking (i.e., yige vs. yixie, or –men), yet they did distinguish between singular and plural sets in manual search. These experiments suggest that knowledge of singular–plural morphology is not necessary for deploying the nonlinguistic distinction between singular and plural sets.

Children can determine the meaning of a new word from hearing it used in a familiar context—an ability often referred to as fast mapping. In this paper, we study fast mapping in the context of a general probabilistic model of word learning. We use our model to simulate fast mapping experiments on children, such as referent selection and retention. The word learning model can perform these tasks through an inductive interpretation of the acquired probabilities. Our results suggest that fast mapping occurs as a natural consequence of learning more words, and provides explanations for the (occasionally contradictory) child experimental data. 1 Fast Mapping An average six-year-old child knows over 14,000 words, most of which s/he has learned from hearing other people use them in ambiguous contexts (Carey, 1978). Children are thus assumed to be equipped with powerful mechanisms for performing such a complex task so efficiently. One interesting ability children as young as two years of age show is that of correctly and immediately mapping a novel word to a novel object in the presence of other familiar objects. The term “fast mapping ” was first used by Carey and Bartlett (1978) to refer to this phenomenon. Carey and Bartlett’s goal was to examine how much children learn about a word when presented in an ambiguous context, as opposed to concentrated teaching. They used an unfamiliar name (chromium) to refer to an unfamiliar color (olive green), and then asked a group of four-year-old children to select an object from among a set, upon hearing a sentence explicitly

One of the deepest and most ancient problems in philosophy is what we might call the problem of knowledge. There seems to be an unbridgeable gap between our abstract, complex, highly structured knowledge of the world, and the concrete, limited and confused information provided by our senses. Since the Meno, there have been two basic ways of approaching this problem, rationalism and empiricism. Each era seems to have its matched pair of advocates of each view, making their way through the centuries like couples in some eternal philosophical gavotte, Plato and Aristotle, Descartes and Locke, Leibniz and Berkeley, Kant and Mill. The rationalist approach says that although it looks as if we learn about the world from our experience, we don’t really. Actually, we knew about it all along. The most important things we know were there to begin with, planted innately in our minds by God or evolution (or chance). The empiricist approach says that although it looks as if our knowledge is far removed from our experience, it isn’t really. If we rearrange the elements of our experience in particular ways, by associating ideas, or putting together stimuli and responses, we’ll end up with our knowledge of the world. There is both a tension and a kind of complementarity between these two ideas,

There is currently rather little agreement about the existence of, and explanation for, a vocabulary spurt in children during the second year. Here we apply a Functional Data Analysisbased technique called Automatic Maxima Detection to the problem of finding vocabulary spurts in a sample of 20 children. Even with considerable smoothing of the data, children were found to exhibit multiple vocabulary spurts of varying intensity and location. These results should provide a clearer target for researchers interested in detecting and explaining these deviations from linear growth.