|Institution:||University of British Columbia|
|Full text PDF:||http://hdl.handle.net/2429/50096|
An inherent difficulty for infants learning their first language is that when a caregiver presents a name for an object there are many possible referents of the label. For example, the new word could refer to an individual (proper name), a category (count noun), or a property (adjective). Here I explored how infants might identify a novel word’s lexical category and limit its possible meaning. Research has revealed that infants appear to possess an early expectation that a consistent word applied to multiple objects labels a category, in the manner of count nouns (see Waxman & Gelman, 2010). At the same time, studies suggest that hearing distinct labels for a set of objects can serve to highlight contrasts among the objects (Xu, 1999). Labels can contrast objects from one another in a number of different ways (e.g., contrastive count nouns, adjectives, proper names). Yet some types of contrasts may be more salient for some kinds of objects than for others. Although distinct labels might pick out subordinate categories (i.e., count nouns) or distinguishing properties (i.e., adjectives) for objects of any kind, only in the case of people are distinct labels likely to pick out individuals (i.e., proper names) (see Hall, 2009; Macnamara, 1982). We propose that hearing distinct words highlights contrasts between people more so than contrasts between artifacts or other animals. Fourteen-month-old infants viewed images of emus paired with images of female faces. Infants who heard the same label for every pair behaved like infants who heard no labels, and did not preferentially select a new face or new emu for the referent of the same word. In contrast, when infants heard a different label for each face-emu pair, they selected a new face as the referent of a novel word. These findings are consistent with the possibility that infants inferred that distinct labels function to pick out contrasts between people as opposed to contrasts between nonhuman animals. We will discuss how these results bear on the issue of how infants learn the way in which words from different lexical classes are marked in their language.