Two studies investigated the effect of microcomputers on children's social behavior in preschool classrooms. The first study was conducted at a university nursery school; the second took place at a university day care center. Guided by a list of behaviors selected from the Friedrich and Stein Observation Scale, observations were made at both settings during a 1-hour free-play period. Twelve social behaviors were categorized as prosocial, antisocial, or neutral. A microcomputer and age-appropriate software were introduced into each classroom according to the following schedule of treatment weeks: baseline, computer-noninteractive (omitted in the second study), computer-interactive, and computer-interactive/teacher-interactive. Except for level of antisocial behavior, results indicated few differences in social interaction patterns between the microcomputer and other free-play choice areas. Critical factors related to the level of antisocial behaviors within the microcomputer area appeared to be the ratio of children to microcomputers and the amount of structure provided by the teacher. Contrary to the predictions of some, the computer did not diminish children's social interactions. (Author/RH)