Studies on Video Game Violence

In 2006, an 18-year-old named Devin Moore was arrested in Alabama on suspicion of car theft. The police officers brought him into the station and started booking him without any trouble. Minutes later, Moore attacked one police officer, stole his gun, shot him and another officer and then fled down the hall and shot a 9-1-1 dispatcher in the head. He then grabbed a set of car keys on his way out the back door, got in a police car and drove away.

Moore had no criminal history. According to the lawsuit filed against video game companies after the incident, Moore had been playing a lot of Grand Theft Auto before the killings [source: CBS News]. At least on the surface, the connection between Moore's game play and his real actions is logical: In "Grand Theft Auto," players steal cars and kill cops.

But the argument is an old one. We've heard it for decades about violent TV. Science has come to a general consensus that violent TV does have an effect on kids' behavior, although doesn't say it causes children to act out the violence they see on the screen.

The basic claim in the video-game controversy is that video games are even more likely to affect people's behavior than TV because they're immersive. People don't just watch video games; they interact with them. The games are also repetitive and based on a rewards system. Repetition and rewards are primary components of classical conditioning, a proven psychological concept in which behavioral learning takes place as a result of rewarding (or punishing) particular behaviors. Also, since the brains of children and teens are still developing, they would, in theory, be even more susceptible to this type of "training."

There's some evidence to this effect, including a study reported in the journal "Psychological Science" in 2001. The report is an overall analysis of 35 individual studies on video game violence. It found several common conclusions, including:

• Children who play violent video games experience an increase in physiological signs of aggression. According to the authors behind the meta-analysis, when young people are playing a violent video game, their blood pressure and heart rate increases, and "fight or flight" hormones like adrenaline flood the brain. The same thing happens when people are in an actual, physical fight. One study even showed a difference in physical arousal between a bloody version of "Mortal Kombat" (a fight-to-the-death game) and a version with the blood turned off.

• Children who play violent video games experience an increase in aggressive actions. A 2000 study involving college students yielded interesting results. The study had two components: a session of video-game play, in which half the students played a violent video game and half played a non-violent video game, and then a simple reaction-time test that put two of the students in head-to-head competition. Whoever won the reaction-time test got to punish the loser with an audio blast. Of the students who won the reaction-time test, the ones who'd been playing a violent video game delivered longer, louder audio bursts to their opponents.

One of the most recent studies, conducted in 2006 at the Indiana University School of Medicine, went right to the source. Researchers scanned the brains of 44 kids immediately after they played video games. Half of the kids played "Need for Speed: Underground," an action racing game that doesn't have a violent component. The other half played "Medal of Honor: Frontline," an action game that includes violent first-person shooter activity (the game revolves around the player's point of view). The brain scans of the kids who played the violent game showed increased activity in the amygdala, which stimulates emotions, and decreased activity in the prefrontal lobe, which regulates inhibition, self-control and concentration. These activity changes didn't show up on the brain scans of the kids playing "Need for Speed."

If so much evidence points to a relationship between virtual aggression and real-world aggression, why are impressionable kids still playing "Mortal Kombat?" On the next page, we'll see why the issue isn't quite so cut and dry.