The Development of Categorization in the Second Year and Its Relation to Other Cognitive and Linguistic Developments.

GOPNIK, ALISON, and MELTZOFF, ANDREW. The Development of Categorization in the Second Year and Its Relation to Other Cognitive and Linguistic Developments. CHILD DEVELOPMENT, 1987, 58, 1523-1531. We report changes in children's categorization behavior between 15 and 21 months of age and relate them to developments in language, object permanence, and means-end understanding. 12 children were studied longitudinally from 15 to 20 months. The children received 3 tasks involving the spontaneous categorization of a mixed array of objects and also received object-permanence and means-ends tasks. Their language development was also recorded. There was an invariant developmental sequence of 3 kinds of active categorization behavior. There were strong relations between the development of the highest-level categorization behavior, 2-category grouping, and the onset of the naming explosion. The highest-level categorization behavior was not strongly related to the attainment of the highest-level object-permanence and means-ends behaviors, though all 3 of these behaviors emerged at about the same age, 18 months. The findings support "the specificity hypothesis," according to which there are certain very specific relations between semantic developments and conceptual developments. Children acquire early words that are relevant to the specific cognitive problems that interest them.