Object properties and knowledge in early lexical learning.

The ease with which young children learn object nouns suggests that they possess strategies to identify properties critical to lexical category membership. In previous work, young children used a same-shape criterion to extend new count nouns. The present research tested the generality of this shape bias. 2- and 3-year-olds were asked either to extend a novel count noun to new instances, or to choose unnamed objects to go together. The objects varied in shape, size, and texture. For half of the subjects, the objects had eyes--a property strongly associated with certain material kinds. If young children know this association, they should attend to texture as well as shape in classifying objects with eyes. With named objects only, both 2- and 3-year-old children classified eyeless objects by shape and objects with eyes by both shape and texture. The results suggest that very young children possess considerable knowledge about conditional relations between kinds of perceptual properties. Knowledge of such conditional relations may aid children in forming new categories and thus in discovering new word meanings.