This study tests the hypothesis that children who viewed videotaped aggression would imitate aggressive behaviors more frequently than would children who were not exposed to aggressive displays. A cognitive factor, reinforcement value, was also hypothesized to be a significant variable in the behavior of the children. Prior to treatment, subjects rated 15 toys for reinforcement value by coloring either a "happy" or a "sad" face to indicate like or dislike, respectively. Ratings were used to match subjects in experimental and control groups. Thirty-two first and second grade boys and girls then viewed and rated for reinforcement value 15 videotaped vignettes in each of which an adult male used one of 15 toys to perform one of 15 different aggressive acts against a bobo doll. Control group children did not view the vignettes. Following the vignettes, combined vignette and pre-experimental toy ratings were used as a basis for selecting eight toys for placement in a play room which contained a bobo doll. Subjects were observed at play in the room for five minutes by trained observers who recorded aggressive behavior. Among the results it was found that experimental group children exhibited significantly more aggressive behaviors than did control subjects, that boys exhibited significantly more imitative aggression than did girls. Further, reinforcement value was a significant factor in the imitative behavior of the children. (Author/RH)