Differences in simple and complex social behavior were examined between monkeys reared with either animate, though nonconspecific, or inanimate surrogate mothers. In the first experiment, members of each rearing condition were formed into 6-member social groups for ten 5.5-hr trials. In the second experiment, members of each rearing condition were formed into social groups twice daily, one formation comprising all 6 group-members and one comprising 5 group-members, with a different individual excluded each day. Although members of both groups displayed deficient forms of social behavior, individuals reared with animate companions were able to use their limited social repertoires in more sophisticated ways, depending upon the social context. The results are discussed in terms of two "tasks" of social ontogeny, the acquisition of behavioral and social competences.