A new report by Dr. Christopher Ferguson claims there's no real link between violent video games and violent behavior:
His introduction recognizes the challenges of studies of the topic. "It is not hard to 'link' video game playing with violent acts if one wishes to do so, as one video game playing prevalence study indicated that 98.7 percent of adolescents play video games to some degree," he writes, "However, is it possible that a behavior with such a high base rate (i.e., video game playing) is useful in explaining a behavior with a very low base rate (i.e., school shootings)? Put another way, can an almost universal behavior truly predict a rare behavior?"
To avoid these problems, he crafted a set of stringent collection criteria: he included only studies that used violent games and measured actual aggressive behavior, rather than scoring violent thoughts or taking physiological measurements. These criteria give a fair measure of the problems the field faces, as only 17 published studies over a 12-year period qualified. That set of 17 also showed a severe publication bias. When the bias was controlled for, there was no significant link between the games and aggression.
Perhaps as a point of comparison, Ferguson also looked at a second phenomenon previously linked with gaming: spatial reasoning criteria. Here, the body of evidence is even smaller: only seven studies during the same time period, also suffering from a strong publication bias. Despite this weakness, the apparent link between violent games and visuospatial cognition is so strong that it remains significant even after controlling for the bias.