It was a different approach than most other studies, which have focused on laboratory experiments that attempt to use actions like ringing a loud buzzer as a measure of aggression.

"What we did that had rarely been done by other researchers was actually talk to the kids. It sounds bizarre but it hadn't been done," Kutner said.

They found that playing video games was a near-universal activity among children, and was often intensely social. But the data did show a link between playing mature-rated games and aggressive behavior.

The researchers found that 51 percent of boys who played M-rated games -- the industry's equivalent of an R-rated movie, meaning suitable for ages 17 and up -- had been in a fight in the past year, compared to 28 percent of non-M-rated gamers.

Photograph for representational purposes only.

Photograph: stock.xchang