Since the early 1960s, research evidence has been accumulating that suggests that exposure to
violence in television, movies, video games, cell phones, and on the Internet increases the risk of
violent behavior on the viewer’s part, just as growing up in an environment filled with real violence
increases the risk of them behaving violently. In the current review this research evidence is
critically assessed and the psychological theory that explains why exposure to violence has detrimental
effects for both the short and long-term is elaborated. Finally the size of the “media violence
effect” is compared with some other well-known threats to society to estimate how important a
threat it should be considered. © 2007 Society for Adolescent Medicine. All rights reserved.