Brad Bushman, Margaret Hall and Robert Randal Rinehart Chair of Mass Communication, is co-author of a new study providing  the first experimental evidence that the negative effects of playing violent video games can accumulate over time.

Although other experimental studies have shown that a single session of playing a violent video game increased short-term aggression, this is the first to show longer-term effects, said Bushman. "It's important to know the long-term causal effects of violent video games, because so many young people regularly play these games," he added.

Bushman conducted the study with Youssef Hasan and Laurent Bègue of the University Pierre Mendès-France, in Grenoble, France, and Michael Scharkow of the University of Hohenheim in Germany.

Researchers found that people who played a violent video game for three consecutive days showed increases in aggressive behavior and hostile expectations each day they played. Meanwhile, those who played nonviolent games showed no meaningful changes in aggression or hostile expectations over that period.

"Playing video games could be compared to smoking cigarettes,” Bushman said. “A single cigarette won't cause lung cancer, but smoking over weeks or months or years greatly increases the risk. In the same way, repeated exposure to violent video games may have a cumulative effect on aggression."

Study results are published online in the Journal of Experimental Social Psychology and will appear in a future print edition.

Read the press release, courtesy of Jeff Grabmeier, director, research and innovation communications.