There's now neurological proof that video games make players more aggressive and violent.

A new study reveals that the more violent games people play, the more desensitized their brains become to violence. The diminished response to violence actually causes more aggressive behavior.

"Many researchers have believed that becoming desensitized to violence leads to increased human aggression," said Bruce Bartholow, associate professor of psychology at the University of Missouri.

"Until our study, however, this causal association had never been demonstrated experimentally."

Study details

A group of 70 young adults were tested, with some playing nonviolent video games while others played popular violent video games like "Call of Duty" and "Grand Theft Auto," each for 25 minutes.

Following their play time, the participants had their brains scanned while they looked at photos of either neutral or violent events. They would then compete against an opponent by blasting a loud noise at them, with the volume of the noise determining their aggression.

The participants that played the violent games were more aggressive in their noise level choices than those who didn’t play violent games.

Those participants who didn’t play many violent video games outside of the experiment, and played violent games during the experiment, displayed reduced brain responses when shown violent pictures.

Reduced Brain Responses

The players who played violent games outside of the experiment exhibited reduced brain responses when shown violent images regardless of the type of game played during the experiment.

Barthlow called for future research on the matter, specifically research that sought to moderate the effects of violent media on children.

"From a psychological perspective, video games are excellent teaching tools because they reward players for engaging in certain types of behavior," he said.

"Unfortunately, in many popular video games, the behavior is violence."

The study will appear in a forthcoming issue of the Journal of Experimental Psychology.