ANN ARBOR—Watching media violence significantly increases the risk that a viewer or video game player will behave aggressively in both the short and long term, according to a University of Michigan study published today in a special issue of the Journal of Adolescent Health.

The study, by L. Rowell Huesmann, reviews more than half a century of research on the impact of exposure to violence in television, movies, video games and on the Internet.

“The research clearly shows that exposure to virtual violence increases the risk that both children and adults will behave aggressively,” said Huesmann, the Amos N. Tversky Collegiate Professor of Communication Studies and Psychology, and a senior research scientist at the U-M Institute for Social Research (ISR).

In his article, Huesmann points out that U.S. children spend an average of three to four hours a day watching television. “More than 60 percent of television programs contain some violence,” he said, “and about 40 percent of those contain heavy violence.

“Children are also spending an increasingly large amount of time playing video games, most of which contain violence. Video game units are now present in 83 percent of homes with children,” he said.

According to research conducted by Huesmann and ISR colleague Brad Bushman, media violence significantly increases the risk that both children and adults will behave aggressively.

How significantly?

“Exposure to violent electronic media has a larger effect than all but one other well-known threat to public health. The only effect slightly larger than the effect of media violence on aggression is that of cigarette smoking on lung cancer,” Huesmann said.

“Our lives are saturated by the mass media, and for better or worse, violent media are having a particularly detrimental effect on the well-being of children,” he said.

“As with many other public health threats, not every child who is exposed to this threat will acquire the affliction of violent behavior. But that does not diminish the need to address the threat—as a society and as parents by trying to control children’s exposure to violent media to the extent that we can.”

The supplement was funded by the Centers for Disease Control and Prevention.