3 words destroy the entire, flimsy hypothesis of how video game violence is dangerous:
CORRELATION, NOT CAUSATION!!!
This needs to be drilled into the heads of kids in middle school and onward, it is so important. Seriously. Lack of this knowledge causes so many failures to understand reality on a most basic level, I honestly think it comparable in importance to literacy. Yes, literacy. In general.
Here's why video game violence studies fail. How does this sort of study get performed? Well, there is a bunch of ways. One is by presenting a sample group with a video game, and measuring, "Aggression". But since we can't take out a tape measure and measure aggression, we have to make measurements up. And no one has made a measurement that has any external validity (That is, a measurement of aggression which would be a true predictor of real life aggression). There are 3 major reasons for this. One is Bias. Experimenters with agendas are certainly a big problem, but so is participant bias. When a participant is presented a video game that contains violence, and are then given some measurement of aggression, they know exactly whats going on. They know that the experimenters are looking for aggression. And they naturally want to conform to experimenters expectation. Participants will willingly electrocute crying people with heart conditions if a researcher asks, of course they are going to report aggression if it is clearly what the researcher wants (Check out Milgram and the Stanford Prison study for this). You cannot rely on this data. Secondly, aggression is a nebulous concept to begin with, and the implication that aggression causes violence is both necessary for the hypothesis, and very, very false. Aggression can also mean arousal, passion, pro-active actions, and dedication. Aggression is just as likely to mean being pumped up for a session of friendly boxing as it does wanting to hurt someone. Assumptions that cannot be made are being made. And lastly, you never see a proper metric by which to judge aggression. You always see video games and a control. Because we have no comparison, one can only conclude that, logically, movies, football, a dose of caffine, bad weather, a heated debate, or a competitive chess match could cause the exact same amount of aggression as a violent video game. Most researchers doing this sort of thing don't like acknowledging that fact, however.
Another option for research is archival data. Go through a list of troubled kids, and find which ones like video games. This is actually pretty common, and is even worse then above. There are innumerable, far more realistic alternative hypotheses which explain this mere correlation. Perhaps an already violent kid will be drawn to, well, violence? Perhaps a child whose parents are so absent that they let there 12 year old play Manhunt isn't being raised in an environment conducive to pro social behavior? Perhaps troubled kids tend to be loners, lack social skills, and few friends, and therefore Video Games are one of the only options available? Perhaps other people consider Games to be a red flag, and only notice troubled kids who also like video games? All of these are far more likely scenarios then video games magically reprogramming synapses in the brain.
What sort of study would actually provide even some evidence that video games cause violence? Researchers don't want to slowly piece together a coherent understanding from a wide variety of information sources that diminish the effect of experimenter bias, because it won't make the people funding them happy. So the only real way to test for this would be...
Illegal.
Yes, illegal. The only real way to test for this is a proper experiment. A proper experiment would involve assigning kids to play violent games, and measuring how violent they become. Let me just point out that if this study was done, you still can't trust it, because it is a grotesque breach of ethics which no IRB would be capable at glancing at without sending men with long knives after the evil person behind the experiment. It is attempting to cause violence against kids. Researchers know this, and know how much more difficult it would be to do the long, hard, drudging work to get real answers. So they rely entirely on deeply, deeply flawed studies. It confirms there bias, so why not? Except it is not real science, it's shallow political scapegoating with all the scientific merit of Phrenology.
Granted that none of this actually disproves the hypothesis, but so far, the evidence is leaning towards the gamers. Certainly reasonable people agree that there is content in games which is not kid friendly. However, I think its clear that we can put this fear of brainwashing into the junk pile, and hopefully, we can put this fear-mongering behind us. Or at least say that were going to have to ban football long before we ban Video games, because the violence there is far more observable.