Infants' On-line Segmentation of Dynamic Human Action

Previous research has clarified that infants from 10–11 months segment dynamic human action into units coinciding with actor's goals and intentions (Baldwin, Baird, Saylor, & Clark, 2001 Baldwin, D. A., Baird, J. A., Saylor, M. M. and Clark, M. A. 2002. Infants detect structure in human action: A first step toward understanding others’ intentions?. Child Development, 72: 708–718. Google Scholar). In this study, we explored the scope and robustness of early action segmentation skills by exposing infants to a variety of relatively novel events in the absence of an extensive familiarization period. Infants from 9–11 months viewed two simultaneous displays of live action, each involving a single actor manipulating a different set of objects. While the actors were in continuous motion, tones were presented that corresponded with the completion points of one of the actor's intentions. Infants revealed segmentation skills by looking longer at the action sequence matching the tone presentation than at the other action sequence. Neither repeated presentation nor the salience of the matching actions accounted for the finding. The segmentation skills revealed in this study may lay the foundation for infants’ eventual ability to make sense of others’ actions and intentions.