Words as invitations to form categories: evidence from 12- to 13-month-old infants.

Recent research has documented specific linkages between language and conceptual organization in the developing child. However, most of the evidence for these linkages derives from children who have made significant linguistic and conceptual advances. We therefore focus on the emergence of one particular linkage--the noun-category linkage--in infants at the early stages of lexical acquisition. We propose that when infants embark upon the process of lexical acquisition, they are initially biased to interpret a word applied to an object as referring to that object and to other members of its kind. We further propose that this initial expectation will become increasingly specific over development, as infants begin to distinguish among the grammatical categories as they are marked in their native language and assign them more specific types of meaning. To test this hypothesis, we conducted three experiments using a modified novelty-preference paradigm to reveal whether and how novel words influence object categorization in 12- to 13-month old infants. The data reveal that a linkage between words and object categories emerges early enough to serve as a guide in infants' efforts to map words to meanings. Both nouns and adjectives focused infants' attention on object categories, particularly at the superordinate level. Further, infants' progress in early word learning was associated with their appreciation of this linkage between words and object categories. These results are interpreted within a developmental and cross-linguistic account of the emergence of linkages between linguistic and conceptual organization.