This is a really bad thing. I would really try to stop supporting this (where does he get money to buy these games?
Here are three recent sources - this is well known in psychological and psychiatric research - only the issue gets clouded by lots of money flooding in (from video game companies) to try to make the issue seem controversial. Its not controversial in scientific communities.
Research has long shown a cause-effect relationship between television violence and aggression among children and youth who watch it. Many social scientists expect video games to have an even greater impact for the following four reasons:
Children are more likely to imitate the actions of a character with whom they identify. In violent video games, players participate as a character, and even choose which weapons they’ll use while fighting other characters.
Video games by their very nature require active participation rather than passive observation.
Repetition increases learning. Video games involve a great deal of repetition. If the games are violent, then the effect is a behavioral rehearsal for violent activity.
Rewards increase learning, and video games are based on a reward system.
****Myths and Facts
Myth 1. Violent video game research has yielded very mixed results.**
Facts: Some studies have yielded nonsignificant video game effects, just as some smoking studies failed to find a significant link to lung cancer. But when one combines all relevant empirical studies using meta-analytic techniques, five separate effects emerge with considerable consistency. Violent video games are significantly associated with: increased aggressive behavior, thoughts, and affect; increased physiological arousal; and decreased prosocial (helping) behavior. Average effect sizes for experimental studies (which help establish causality) and correlational studies (which allow examination of serious violent behavior) appear comparable (Anderson & Bushman, 2001).
Myth 2. The studies that find significant effects are the weakest methodologically.
Facts: Methodologically stronger studies have yielded the largest effects (Anderson, in press). Thus, earlier effect size estimates -based on all video game studies- probably underestimate the actual effect sizes.**
New research suggests that hours of exposure to violent media like video games can make kids react in more hostile ways compared to ones who don't spend lots of time controller-in-hand, reigniting the debate about children and gaming
Ever since Columbine, in which two students went on a deadly rampage at their high school, television, movies, and video games have been a popular target for senseless acts of violence.
“What this study does is show that it’s media violence exposure that is teaching children and adolescents to see the world in a more aggressive kind of way,” says Anderson. “It shows very strongly that repeated exposure to violent video games can increase aggression by increasing aggressive thinking.”
Brain imaging studies also hint that exposure to violent gaming may actually temporarily change the brain. In a 2011 study, for example, after a week of daily video gaming, brain scans of a small group of volunteers showed less activity in the regions connected to emotions, attention, and inhibition of impulses compared to participants who played non-violent video games. The effect appeared to be reversible, but the results suggested that extended periods of play could lead to more stable changes in the brain.