What I can't believe is that anyone takes this seriously, it's like there wasn't any violent behavior among humans before the advent of video games and other violent media. Overall we live in perhaps the most violence-free period in human history overall... which with all the violence going on gobally probably isn't saying much. To be honest people in the first world can go about their entire lives without being involved in any real violence, while that's only the first world, it still represents a larger percentage of human safety and freedom from actual violence than we've likely ever seen.
The thing that gets me is that most of the real ultra-violence takes place in areas where people don't play many video games at all, as they have other concerns. You know the guys who look at video game QQing and dismiss it as "a first world issue". It seems to me that you could actually prove (using the same logic from this study) that violent video games decrease violent behavior societally because the societies without video games are more prone to violence and barbarity. Of course that's totally stupid, but it's the same kind of logic.
What I find most disturbing about this is that the implication is that violent behavior is inherantly a problem. I believe people need to be able to control themselves, but being totally peaceful and passive is not a good thing. Especially when you look at the state of the world outside of the first world enclaves, and the problems going on. If anything I think the people of the first world are too passive and anti-violent for their own good on a whole and it's something we're going to regret, pacifying ourselves to the point of not being able to survive. A form of social darwinism where we eventually wind up getting overrun due to our own inabillity to defend ourselves, or willingness to fight and kill on the needed level for our own interests.
That said, another big problem with this is that issue of fun. People tend to forget that the whole point of gaming is to have fun and enjoy themselves. You can't do much gaming in the space of 15 minutes, or learn how to play a game seriously, develop a context for what is going on, or anything else for that matter. This kind of scews any kind of study involving gaming, especially if it involves people who are allegedly not gamers and thus lack any real context.
If these games are intended to expose the people to ultra violence in a game in 15 minutes there can't be much else going on there. I suppose if someone put me in a room and basically tossed me a limited section of "Manhunt" which involved the director telling me to draw a knife accross some victim's crotch or whatever, without any other context to the game or whatever, I'd think it was pretty screwed up, since your basically handling me an interactive snuff flick. As a horror fan I can say "well, that's disturbing but I've seen worse" to someone without that kind of experience I can see an increase in the "WTF" factor. To really evaluate the reaction to a game, the experience has to be taken as a whole, to use Manhunt as an example, the messed up things that happen are held together by a narrative. Slicing people up on command in a 15 minute session, is far differant than the gradually developed subtext of being forced into a televised deathmatch and comply with doing this crap or die, and going along with it in hopes of escaping... and of course taking down the sick puppet master behind all of this stuff. It's not a storyline that might be fun to everyone, but the context DOES matter, and games pretty much always have a context. As games become more advanced graphically, leading to all of these criticisms about violence, so does the context behind those actions, and yet nobody ever bothers to make that point in these studies, and those involved seem to even go so far as to ensure it's impossible for the guinea pigs to put the violence into any kind of context.