Mapping the similarity space of children and adult's artifact categories

Most theorists agree that people's categorization of artifacts is influenced by two factors: (a) in what respect objects are similar, and (b) to what degree objects are similar. Research with children has identified two respects - physical appearance and function - which are important for the categorization of artifacts. Previous work, however, has not mapped decisively the relative contribution of each of these respects to children's categorization decisions. In the present study, children and adults were shown a novel standard object and were asked to categorize 10 test objects of varying degrees of physical and functional similarity to the standard. We found that while adults included as category members objects of high functional similarity even if of low physical similarity, children accepted as members only objects that were highly similar to the standard both functionally and physically. In other words, children and adults weighted functional similarity comparably, but children gave more weight than adults to physical similarity. These results may help illuminate the conflicting findings and theories on the development of artifact categories.