From The British Psychological Society's Research Digest:
After Aaron Alexis shot dead 12 people at the Navy Yard in Washington DC in September, media outlets were quick to highlight his reported enjoyment of violent video games. To many, this was just the latest example of how violent games can foster real-life aggression. There is research supporting such a link, although experts are far from reaching a consensus view on the matter. Take, for example, the letter written in September by a group of 230 scholars, calling for the American Psychological Association to adopt a more nuanced position on the nature of the evidence.
A refrain from many sceptical researchers in this field is that the situation is complex. To claim baldly that violent video games cause real-life aggression is an oversimplification, they say. Now a brief but elegant new study has done a useful job highlighting some of these intricacies.
Effects of a violent video game depend on whether you're Superman or the Joker