FORMING CONTEXTUAL CATEGORIES IN INFANCY

The role of context in categorization was examined in four experiments with 3-month-olds. In all experiments infants learned to kick their f eet to activate a mobile on 3 successive days. Infants were trained wi th a different mobile exemplar during each daily session. Categorizati on of a physically dissimilar novel object (Butterfly) was assessed 1 to 14 days later. In Experiments 1A and 1B, infants were trained and t ested in a highly distinctive context. They included Butterfly in the mobile category after 1 and 7, but not after 14, days (Experiment 1A). This latter result was due to a categorization failure because infant s did respond to another novel exemplar of the original training serie s after 14 days (Experiment 1B). In Experiment 2A, infants who were pa ssively exposed to Butterfly for 3 minutes in the distinctive context at the end of category training responded to Butterfly 1 day later whe n it was encountered ''out of context.'' This result was also obtained in Experiment 2B when the distinctive context was present only during the final training session. Taken together, these findings demonstrat e that categorization of a novel object is influenced by the context p resent when the object is initially encountered and by previous encoun ters with that object in the category context. Clearly, infants are ca pable of contextual categorization very early in the first year of lif e.