The idea that violent video games generate violence in real life has had social currency for years; it's now widely accepted enough that it turns up as a truism in unrelated articles. But Harvard economist Lawrence Katz believes that video games may actually depress the violent-crime rate by keeping people occupied in a peaceful manner. As David Leonhardt put it in a recent New York Times piece:

Video games can not only provide hours of entertainment. They can also give people -- especially young men, who play more than their fair share of video games and commit more than their fair share of crimes -- an outlet for frustration that doesn't involve actual violence. Video games obviously have many unfortunate side effects. They can promote obsessive, antisocial behavior and can make violent situations seem ordinary. But might video games also have an upside? I'm willing to consider the idea.
Katz admits that his findings are far from conclusive, though Leonhardt goes on to note that another study drew a similar link between violent movies and the suppression of real-life violence in 2008. Either way, Katz's theory is sure to be of interest to parents or lawmakers with a stake in the video-game regulation question.