Effects of knowledge and development on subordinate level categorization

Children and adults with high, moderate, and low levels of dinosaur knowledge were provided with a series of tasks to determine the relative effects of knowledge and development on subordinate category extension, differentiation, and subsequent revision. As knowledge increased, individuals generated higher proportions of category underextensions and lower proportions of overextensions. Adults, but not children, who were highly knowledgeable about dinosaurs demonstrated similar patterns of extension for unfamiliar categories, suggesting that knowledge transfer is mediated by age-related strategies. Adults at all levels of knowledge were more likely to revise their category extensions than children were. The relation between intelligence and expertise in object domains is considered and a preliminary model of the effects of knowledge and development on skill at categorization is presented.