Preschoolers' extension of novel words to animals and artifacts.

We examined whether preschoolers' ontological knowledge would influence lexical extension. In Experiment 1, four-year-olds were presented with a novel label for either an object with eyes described as an animal, or the same object without eyes described as a tool. In the animal condition, children extended the label to similar-shaped objects, whereas in the tool condition, children extended the label to similar-function objects. In Experiment 2, when four-year-olds were presented with objects with eyes described as tools, they extended the label on the basis of shared function. These experiments suggest that preschoolers' conceptual knowledge guides their lexical extension.

Infants' categorization of novel objects with more or less obvious features.

In five experiments, 14- to 15-month-old infants' categorization of objects on the basis of more or less obvious features was investigated. Using an object examining paradigm, a total of 200 infants were familiarized with novel objects that shared either more obvious features (i.e., easily visible) or less obvious features (i.e., accessible by lifting a flap), followed by an in-category object and an out-of-category object. When only perceptual information was available, infants formed a category on the basis of the more obvious features but not on the basis of the less obvious features (Experiments 1 and 3). When infants were provided with animacy cues and/or object names, they formed categories on the basis of either more or less obvious features (Experiments 2, 4, and 5). The results of these studies delineate the role of animacy cues and object names in establishing categories on the basis of less obvious features.

Preschoolers' extension of familiar adjectives.

In two experiments, we examined the role of labels in guiding preschoolers' extension of three types of familiar adjectives: emotional state adjectives, physiological state adjectives, and trait adjectives. On each trial, we labeled a target animal with one of the three different types of adjectives and asked whether these terms could apply to a subordinate-level match, a basic-level match, a superordinate-level match, or an inanimate object. In Experiment 1, participants extended trait adjectives, but not emotional or physiological adjectives, to members of the same basic-level category, regardless of whether an explicit basic-level label was provided for the target animal. Similarly, children in Experiment 2 also extended trait adjectives to the members of the same basic-level category, even when explicit superordinate- and subordinate-level labels were provided for the target animals. Together, these results demonstrate that children appreciate that emotional and physiological adjectives cannot be generalized to the same extent as can trait adjectives, and the results document the privileged status of basic-level categories in preschoolers' extension of trait adjectives.

Thirteen-month-olds rely on shared labels and shape similarity for inductive inferences.

This study examined the influence of shape similarity and labels on 13-month-olds' inductive inferences. In 3 experiments, 123 infants were presented with novel target objects with or without a nonvisible property, followed by test objects that varied in shape similarity. When objects were not labeled, infants generalized the nonvisible property to high-similarity objects (Experiment 1). When objects were labeled with the same noun, infants generalized the nonvisible property to high- and low-similarity objects (Experiment 2). Finally, when objects were labeled with different nouns, infants generalized the nonvisible property to high-similarity objects (Experiment 3). Thus, infants who are beginning to acquire productive language rely on shared shape similarity and shared names to guide their inductive inferences.

Hot dogs and zavy cats: preschoolers' and adults' expectations about familiar and novel adjectives.

In recent years, a growing body of research has begun to examine the processes that underlie young children's acquisition of adjectival meanings. In the present studies, we examined whether preschoolers' willingness to extend adjectives was influenced by the type of property labeled by familiar adjectives (Experiment 1) and by semantic information conveyed in the sentence used to introduce novel adjectives (Experiment 2). In Experiment 1, we examined preschoolers' and adults' expectations about the generalizability of familiar adjectives of three different types: emotional state terms, physiological state terms, and stable trait terms. On each trial, we labeled a target animal with one of the three different types of adjectives and asked whether these terms could apply to a subordinate-level match, a basic-level match, a superordinate-level match, or an inanimate object. Results indicated that 4-year-olds and adults extended the trait terms, but not the emotional or physiological terms, to members of the same basic-level category. In Experiment 2, we presented 4-year-olds and adults with novel adjectives in one of two verb frames: stable ("This X is very daxy") or transient ("This X feels very daxy"). Participants were more likely to extend the novel adjective to subordinate matches if they were in the Stable frame group than if they were in the Transient frame group. These findings are discussed in terms of implications for young children's expectations about familiar and novel adjectives.