Five-year-olds' beliefs about the discreteness of category boundaries for animals and artifacts.

Research on adult concepts indicates that category structure varies by domain; adults view membership in animal categories as absolute but membership in artifact categories as graded. In this study, we examined domain differences in beliefs about category boundaries among young children (5-year-olds). The results indicated that young children, like adults, were less likely to endorse graded category membership for animal than for artifact categories. These domain differences could not be attributed to domain differences in typicality. Implications for conceptual development and for models of domain specificity in adult cognition are discussed.