Peer presence and the exploratory behavior of eighteen- and thirty-month-old children.

20 18- and 20 30-month-old children were observed in a situation requiring separation from the mother in order to play with attractive toys. An agemate was present for half the children but not the others. Peer presence facilitated leaving the mother and entering the playroom at both ages. Among 18-month-olds, the presence of the peer also shortened play bouts, increased unoccupied/self-solace behavior, and increased contact maintenance with the mother. Among 30-month-olds, however, the peer's presence did not have these effects. these children engaged in increased coordinate social interaction with the other child. Developmental changes occurring in the second and third year thus include the increased salience of agemates in supporting separation from the mother and exploration of the environment in the context of sustained social interaction.