In the wake of another unthinkable massacre this week in Aurora Colorado most people will be wondering what motivated James Holmes. So far there are very few facts about him and his life. One thing we do know is that he did play a lot of video games. It appears that he was particularly hooked on one called guitar heroes. The question of whether video games are harmful has been a controversial one for some time now, with researchers not agreeing. Maybe this is not surprising. Video-games are big business, and it is also true that they alone would not lead to such a shocking act, and presumably their use was as much a symptom as a cause.
Nonetheless in the last few years the research does seem to be suggesting that violent video games are not good news. One of the most rigorous and influential researchers, Douglas Gentile, of Iowa State University, has for many years been looking at this. He has just published another study  which involved 430 children between the ages of 7 to 11 years. What he discovered is that exposure to media violence is certainly a serious risk factor which predicts aggressive behaviour later on. However it is one of 6 such factors, the others including low parental involvement, gender, bias toward hostility, having been bullied and a history of being in fights physical fights. Gentile reported "As you gain risk factors, the risk of aggression goes up disproportionally. Having one or two risk factors is no big deal. Kids are resilient - they can handle it. You get to three and there's a big jump. When you get out past four risk factors, risk is increasing at a much higher rate than you would expect." Quite rightly Gentile argues that many of these factors one can do little about, but we can try and curb the use of violent videos.
In many research studies Gentile and his colleagues, from Iowa University, who have studied thousands of cases, found that the more time spent playing such games, the more impulsivity and the poorer the concentration, and basically more is worse. Screens and gaming are not very good for us, but violent video games are even more worrying. There is some controversy about how damaging they are but much extensive research suggests bad effects. A recent study showed that exposing children to violent films, whether of physical violence or interpersonal aggression like cyber-bullying or taunting, led to more physically aggressive children than a control group later, and to children who were more verbally aggressive, mean and nasty. This is typical of many studies. Those exposed to violent media, whether games or film, become more reactive and less prosocial and seemingly become primed to see and respond swiftly to any hints of aggression. Not surprisingly such violent game playing had a detrimental effect on their school work, but maybe most importantly, on their peer relationships.
Another striking study of German 20 to 30 year olds showed that clear changes were occurring in the brains of the gamers playing violent video games of a genre called ‘First Person Shooter’. They had heightened amygdala activity, that brain area central to fear and strong emotions. Maybe even more worryingly, the gamers had lower activation in certain areas of their prefrontal regions, and the players were becoming desensitised to powerful negative emotional images. Again with less emotional sensitivity comes lower empathy, less prosocial behaviour and probably more aggression, effects that are still there a year later. Overall what we are seeing is that violent game playing leads to shorter attention spans, less executive control and more likelihood of impulsivity, as well as increased propensity for violence.
We have moved into a much more screen led world in which human relationships play a less central role, and many children are not receiving the kind of human input that mental health professionals think they need. Lack of parental input of course was another of Gentile’s risk factors. We maybe should be worrying about the use of screens generally. The more exposure a three year old has to television, even without any violent content, the more we are likely to see behaviour problems . Worryingly, Ed Mayo and Agnes Nairn in their report on children as consumers in the UK found that it was the least privileged children who were most likely to spend more time in front of a computer. In fact they were nine times more likely to eat a meal in front of a TV and five times more likely to be on a computer before bedtime than their more affluent counterparts. Obviously younger children are especially vulnerable to such influences as their brains are still forming and their personalities growing. However it is true that the jury remains out about the effects of TV and screen-time generally, but the evidence is increasingly clear that we should worry about the effects of violent media.
 D. A. Gentile and B. J. Bushman, ‘Reassessing Media Violence Effects Using a Risk and Resilience Approach to Understanding Aggression’, Psychology of Popular Media Culture, 2012.
 D. A. Gentile, S. Coyne, and D. A. Walsh, ‘Media violence, physical aggression, and relational aggression in school age children: a short‐term longitudinal study’, Aggressive Behavior, vol. 37, no. 2, pp. 193–206, Mar. 2011.
 S. M. Coyne, D. A. Nelson, N. Graham‐Kevan, E. Tew, K. N. Meng, and J. A. Olsen, ‘Media depictions of physical and relational aggression: connections with aggression in young adults’ romantic relationships’, Aggressive Behavior, vol. 37, no. 1, pp. 56–62, Jan. 2011.
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 B. Krahé and I. Möller, ‘Longitudinal effects of media violence on aggression and empathy among German adolescents’, Journal of Applied Developmental Psychology, vol. 31, no. 5, pp. 401–409, 2010.
 W. G. Kronenberger, V. P. Mathews, D. W. Dunn, Y. Wang, E. A. Wood, A. L. Giauque, J. J. Larsen, M. E. Rembusch, M. J. Lowe, and T. Li, ‘Media violence exposure and executive functioning in aggressive and control adolescents’, Journal of Clinical Psychology, vol. 61, no. 6, pp. 725–737, Jun. 2005.
 J. A. Manganello and C. A. Taylor, ‘Television exposure as a risk factor for aggressive behavior among 3-year-old children’, Archives of Pediatrics and Adolescent Medicine, vol. 163, no. 11, p. 1037, 2009.