There has been little systematic research, but one consistent finding is that most studies on very young children tend to show that they become more aggressive after playing or watching a violent video game.
There is also the social context. Does playing in groups or individually, with or against each other make a difference? Recent research suggests that competitiveness increases aggression. There are also problems defining "violent" or "aggressive", as television cartoons such as Tom and Jerry may not be seen as violent within definitions used in media research. Therefore, research into the effects of long-term exposure remains speculative.
DR MARK GRIFFITHS
Nottingham Trent University