Understanding Categorical Hierarchies: The Earliest Levels of Skill

Abstract

2 categorization skills necessary for understanding hierarchies are the ability to form categories at different levels of generality and the ability to include the same objects into multiple categories. 2-year-olds appear to have the first skill, but some theoretical and empirical work suggests that the second may be a later acquisition. Yet, in 3 studies, 2- and 3-year-olds applied familiar basic level and superordinate labels to the same objects, even when reminded of basic labels before being tested with superordinates. They did not reserve superordinates for objects with unfamiliar basic level names (Study 2), and they were willing to apply superordinates to objects presented singly rather than in groups (Study 3). Thus, contrary to the implications of some previous work, 2- and 3-year-olds appear to have both of the categorization skills necessary for forming categorical hierarchies.