The researchers were surprised that the relation to violent video games was so strong.
"We were surprised to find that exposure to violent video games was a better predictor of the students' own violent behavior than their gender or their beliefs about violence
," said Anderson. "Although gender aggressive personality and beliefs about violence all predict aggressive and violent behavior, violent video game play still made an additional difference.
"We were also somewhat surprised that there was no apparent difference in the video game violence effect between boys and girls or adolescents with already aggressive attitudes," he said.