Much of the television American children watch is violent in content. The evidence indicating that this programing increases children's aggressive behavior is not clear-cut, and some studies have shown a decrease in children's aggressive behavior. A study was conducted to test a more developmental perspective on the effects of violent television: that the impact of televised aggression will vary according to the child's cognitive and social developmental level. In an experiment using 119 students from kindergarten, second grade, and fifth grade, the subjects' free playground play was observed during a one-week baseline period, a two-week experimental phase, and a one-week follow-up period. During the experimental phase, subjects were randomly assigned to view for 20 minutes each day either exclusively aggressive or exclusively nonaggressive programing, after which their playground behavior was observed and rated according to 13 categories ranging from physical threat to passive social interaction. The results showed that the older the subjects, the better their comprehension and recall of the shows. Female aggressive behavior was quite low throughout the experiment, but aggressive behavior in boys decreased after they viewed the aggressive segments. Kindergarten children showed more decrease than did fifth grade students, although the fifth grade students better understood the programs they had viewed. (HTH)