Specifying the role of function in infant categorization.

Research demonstrates that object functions facilitate artifact categorization in infancy. To explicate the nature and magnitude of this effect, 16-month-olds participated in three studies. In Experiment 1, categorization was facilitated more by object functions than by distinctive motions, suggesting that the motion properties of function cannot fully explain its influence. In Experiment 2, infants failed to categorize when each category exemplar performed a different function, thus revealing the importance of shared functionality in facilitating categorization. In Experiment 3, infants were tested after each new exemplar was introduced. When object functions were provided during training, infants were more likely to appropriately extend the novel categories on the very first trial. This suggests that function reduces the need for exposure to multiple exemplars in forming categories. Together, these findings confirm the conceptual nature of the facilitative effect of function on early categorization.