How children know the relevant properties for generalizing object names

Young children’s novel word extensions indicate that their animal categories, like those of adults, are characterized by multiple similarities among instances; whereas their artifact categories, again like those of adults, are characterized more simply by commonalities among instances in shape. Three experiments shed light on the nature and development of a mechanism that enables children to organize novel lexical categories differently for different kinds of objects. Experiment 1 shows that, by adult judgments, animals and artifacts present different category organizations. Experiment 2 shows relations between both age and the number of nouns young children have acquired, and children’s kind-specific generalizations of newly learned nouns. Experiment 3 is a training study in which even younger children show an ability to learn and then generalize highly abstract relations between different contextual cues and different category structures; and importantly, to learn more than one set of such relations at a time. Together, these three findings indicate one way in which children are able to rapidly and accurately form lexical categories that parallel those of adults in their language community.