The purpose of this study was to summarize an examination of the social interactions of a sample of 370 preschool children and to demonstrate from the summary that social settings within the preschool environment differentially affect both the quality and quantity of social interaction. The Social Interaction Observation Procedure was used to obtain direct observational data on children's social interactions in the classroom during indoor, free play periods. All children were observed for a minimum of 90 minutes, over a period of at least 15 days. Recorded were social initiations (verbal and/or nonverbal behaviors directed toward another person or persons) and social interactions (initiations followed by response of another person or persons toward whom the initiation was directed). The activities in which the children were engaged were recorded as one of 11 mutually exclusive and exhaustive classes--Role Play, Blocks, Climbing/Running/Tumbling, or Transportation (associated with social behaviors involving peers); Creative Activity, Science and Routines, Books and Records, Table Games and Other (associated with higher rates of social behavior with adults); and Sand or Water Play and Non-Participation. (Author/ED)