Encoding Action Roles in Meaningful Social Interaction in the First Year of Life.

Previous research has shown that 6- to 9-month-old infants detect role reversals in dyadic interaction involving 2-argument relations. These studies extend this line of research to a 3-argument structure: An agent gives an object to a recipient. We conducted 4 experiments in a novelty-preference paradigm. Infants were habituated to videotaped sequences of a puppet giving a flower to another puppet. In the test phase, the puppets' spatial positions were switched, and infants alternately saw role-reversal and direction-reversal trials. Results indicate that 10.5- and 12-month-olds but not 9-month-olds selectively encoded the change of action role (agent-recipient) over a change in the spatiotemporal properties of the interaction and that action role encoding was specific to intentional relations in a 3-argument structure. Thus, infants at the end of their 1st year seem to be sensitive to movement cues that specify intentional relations between an agent and a recipient.