Violent video games could be creating a generation of aggressive teenagers, new research indicates.
It's been known for years that playing such games causes players to become more aggressive, but the mechanism has been unclear. But new research from the University of Missouri concludes that players' brains are actually becoming less responsive to violence, and that this causes the increase in aggression.
"Many researchers have believed that becoming desensitized to violence leads to increased human aggression," says Bruce Bartholow, associate professor of psychology. "Until our study, however, this causal association had never been demonstrated experimentally."
For the study, 70 young adults played either a nonviolent or a violent video game for 25 minutes. Immediately afterwards, the researchers measured brain responses as participants viewed a series of neutral photos - such as a man on a bike - and violent ones, such as a man holding a gun in another man’s mouth.
Finally, the participants competed against an opponent in a task that allowed them to give their opponent a controllable blast of loud noise. The noise level they chose was used as a measure of aggression.
The researchers found that those who played Call of Duty, Hitman, Killzone and Grand Theft Auto set louder noise blasts than the others.
And in those people that hadn't played many violent video games before, playing a violent game in the lab reduced their brain response to the violent photos - indicating desensitization. And this reduced brain response predicted participants’ aggression levels: the smaller the brain response to violent photos, the more aggressive participants were.
People who had already spent a lot of time playing violent video games before the study showed small brain response to the violent photos, regardless of which type of game they played in the lab.
“It could be that those individuals are already so desensitized to violence from habitually playing violent video games that an additional exposure in the lab has very little effect on their brain responses," says Bartholow.
"There also could be an unmeasured factor that causes both a preference for violent video games and a smaller brain response to violence."
The average elementary school child in the US spends more than 40 hours a week playing video games – more than any other activity besides sleeping.
"More than any other media, these video games encourage active participation in violence," says Bartholow. "From a psychological perspective, video games are excellent teaching tools because they reward players for engaging in certain types of behavior. Unfortunately, in many popular video games, the behavior is violence."