The "cause behavior" standard could be read multiple ways.Not too long ago, I wrote a paper on the subject of whether violent video games cause violent behavior (e.g. aggressiveness, lack of empathy) in young adults. Earlier studies had indicated a tentative connection between the two, but later studies done under more rigorous conditions do not point to the same conclusions. In fact, most recent studies were not able to draw a correlation between violent video game play and violent behavior in young adults at all. And in some cases, such as online multiplayer games where the players have to work together as a team to beat a "boss," results showed that such players tended to be more co-operative and engaged in other pro-social behaviors (e.g. sharing, volunteering) in "real life."
Also, there are hardcore gamers all over the world, including in countries with very low violent gun crime rates (e.g. Japan).
Just my two cents.
But do the studies show no correlation with exacerbation of violent behavior?
If this were proven, perhaps we should ditch age restrictions for violent entertainment.