Object function and categorization in infancy: Two mechanisms of facilitation

Does function facilitate categorization by focusing infants' attention generally on all commonalities among objects or specifically on functionally relevant properties? After familiarization to a novel category, 18-month-olds selected another category member from a pair of previously unseen test objects. In Experiments I and 2, infants chose globally similar over functionally similar and novel test objects. Functionally similar and novel test objects were chosen equally. These data suggest that function facilitates categorization through a general attention-enhancing mechanism. However, when functions were more uniquely and transparently tied to object properties in Experiments 3 and 4, infants chose functionally similar over novel test objects. Globally and functionally similar test objects were chosen equally. Therefore, a specific attention-enhancing mechanism also sometimes supports categorization.