Thomas, M. H., & Drabman, R. S. (1975). Toleration of real life aggression as a function of exposure to televised violence and age of subject. Merrill-Palmer Quarterly, 21 (3), 227-232.

Abstract:  Replicates R. Drabman and M. Thomas’s (see record 1974-29879-001) study of increased tolerance for real violence in children repeatedly exposed to filmed violence. Children in the present study varied in age (1st or 3rd grade), sex, and film exposure. There were 10 Ss in each cell of the 2 * 2 * 2 design. The 15-min aggressive film showed excerpts of a popular television show depicting 6 killings and other violent acts. The nonaggressive film showed 15 min of a baseball game. After viewing a film, each S was asked to monitor the behavior of other children and report any violence. 3rd grade Ss who had viewed the violent film were slower to report real violence than 3rd graders who had seen the nonaggressive film. 1st graders were significantly slower to respond, regardless of film treatment. There were no sex differences in responsiveness. (PsycINFO Database Record (c) 2004 APA, all rights reserved)