Not only I doubt the deductions that can be made on a 30-kid sample, but what about the millions of kids around the globe who play violent games on a daily basis, but were never engaged in violent behavior themselves? "More aggressive" doesn't mean "aggressive". One may say that teenagers have been exposed to more and more violence with time, and have become more aggressive, but it doesn't necessarily lead to violent behavior - I was probably more aggressive as a teenager than my mother when she was a teenager, due to the video games I played, but nevertheless I consider myself to be a very non-violent person. I have the gut feeling that Columbine and the likes are not really connected to the kinds of games these kids played, and would have happened regardless - maybe more so since the head of the household had a shotgun in the bedroom? Reminds me of the Metal scandal during the 80's, which was dismissed fairly quickly.