nolimit19 just proved that he didn't READ the article.
It clearly states that the games DO affect people, but other factors in their lives mitigate anything that the violent medium might cause.
The studies you're asking for DO exist, but they're so limited in scope as to be useless. Basically, they have kids play violent games, then watch how they interact for, say, an hour or so after the fact. ADRENALINE is up, and that causes the kids to act aggressively. There are almost NO studies on the LONG TERM effects. Not to mention that none of these stories factors the INDIVIDUAL into the picture, which is incredibly important. Does the kid only have one parent? Do they have many friends? Do they excell in school? Do they have after-school activities?
The point the article makes so well is that you can take the most violent game in the world, stick thousands of people playing the game in the same enclosed space, and not a single fight will occur. The simple ... SIMPLE, social interaction mitigates the effects of the violent game entirely. If it's that simple, then you have to realize that kids that play violent games and then resort to violence are missing significant social interaction in their lives, or simply have something wrong with them to begin with.
I listen to gangsta rap, but I've never shot anyone, or even held a real gun. Nor have I felt any desire to.
I watch violent movies, but I've never felt that violence is a way to solve my problems.
I play violent videogames, but I have yet to feel like going out an mimicking those actions in real life.
My parents are divorced, I wasn't a stellar student, and I didn't have a lot of friends. So how screwed up does a kid have to be to have these influences affect them in a negative and lasting way. Obviously, there are some positive influences in my life that are mitigating the negative stimulus. Kids like the ones behind Columbine are reported to have had very little positive stimulus in their lives. It clearly doesn't take much.
How many times have you heard about a kid from a disadvantaged upbringing turn his whole life around because someone took an interest? Maybe that's all it takes ...