This study analyzed the effect of (1) teacher priming and (2) the presence of novel gross motor play equipment on peer interaction. The subject was a 2 1/2-year-old boy who seldom interacted with his classmates in a toddler class. In the teacher priming condition, teachers verbally and nonverbally prompted the subject to interact with peers, while witholding praise or approval following interactions. In the play equipment condition, one of three novel pieces of gross motor equipment was placed in a special area of the classroom or playground. In a third condition, teachers prompted the subject to "try out" one of the pieces of gross motor equipment, again witholding praise or approval for interactions. Observations were conducted daily during a 20-minute inside free play period and during a 14-minute outside free play period. Behaviors were recorded in 10-second intervals. Results indicate that both the presence of novel play equipment and teacher primes increased the level and duration of appropriate social interaction. Eight pages of graphs and pictures are included. (SB)