Surely someone on Kotaku has noticed this one, published 3rd of July ?
"We failed to find evidence that playing video games affects prosocial behavior. Research on the effects of video game play is of significant public interest. It is therefore important that speculation be rigorously tested and findings replicated. Here we fail to substantiate conjecture that playing contemporary violent video games will lead to diminished prosocial behavior."
A previous study had used classic games and found no effect on being nice to people (prosocial behaviour). To check that more immersive modern games gave the same results they compared Call of Duty, Grand Theft Auto IV, World of Zoo and Portal 2. A separate experiment compared Lamers and Lemmings.
I do wonder why there is an outcry about violent games de-sensitising young people to violence. If we are sensitive to violence we suffer. To live comfortably in the modern world where violence happens regularly it is a positive adaptation to be able to cope with exposure to violence without crippling emotional responses. PTSD is surely an excessive sensitisation leading to inappropriate emotional response to non-threatening stimuli?
The paper also addresses the issue of experiments that show a lack of result being less likely to be published and more often dismissed as "difficult to interpret". New and startling results are more likely to be false-positives and result in publication bias.
The last line in the paper:
However, it remains possible that, in terms of impact on prosocial behavior, public concern over violent video game play should be minimal.