To assess the social interactions between unfamiliar peers, 30 pairs of home-reared children-10 pairs in each of three age groups, 10-12, 16-18, and 22-24 months of age-were observed in an unfamiliar play setting with their mothers. The children contacted their mothers little and interacted more with toys and one another, exchanging smiles, vocalizations, and toys and imitating each other's actions. Contact of the same objects and involvement in the peer's activities with objects increased reliably with age. By 2 years of age, social play exceeded solitary play and the social partner was most often the peer. The results suggested that children generalize to peers behaviors developed through child-adult interaction, but that peers provide stimulation differing from that of familiar adults.Scant attention has been paid to the social interactions between children under two years of age, despite the importance attached to early peer interactions by students of nonhuman primates (e.g., Harlow, 1969;Hinde, 1971) and despite repeated observations of human infants exchanging glances, sounds, smiles, and even toys (e.g., Bridges, 1933; Biihler, 1930;Vincze, 1971). Our knowledge of early human sociability remains limited in large measure to child-mother interactions and to children's initial reactions to unfamiliar adults (e.g., Rheingold & Eckerman, 1973;Schaffer, 1971). Yet the interactions between infant peers may mirror the social development occurring through child-adult interaction; and even more important, interactions with peers may contribute in their own right to early social development.The most comprehensive prior study of interactions between children under 2 years of age is that of Maudry and Nekula (1939), conducted in a foundling home over 30 years This research was supported in part by a Duke University Research Council Grant. We thank Deborah Hotch for her services as an observer and Gregory E.
