We knew this already, but here is more proof

I never agreed with violent video games. I simply don't understand why someone would want to chase or impersonate zombies, decapitate 'enemies,' or shoot 10 different weapons at the same time (virtually)
Even though we all know violent video games positively influence aggressivity, apparently we never had enough proof. Most likely the companies that make these games will never consider such research valid - after all, money comes first - but it's nice to read this; it gives me hope that one day we won't have these games on the market.

It's Conclusive, Claims Professor, Violent Video Games Make Us Aggressive
Matt Peckham Matt Peckham - PC World

An Iowa State psychology professor is claiming--not for the first time--that his latest published study offers irrefutable evidence that exposure to violent video games increases the likelihood of aggressive behavior. And a Texas A&M psychology professor has responded--in the same publication--claiming that the Iowa State study is methodologically flawed.
Published in the March 2010 issue of APA journal Psychological Bulletin, the study by Iowa State professor Craig Anderson, director of Iowa State's Center for the Study of Violence, concludes that exposure to violent video games leads to an increase in aggressive thoughts and behavior, as well as decreased empathy and favorable social behavior in children.
"We can now say with utmost confidence that regardless of research method--that is experimental, correlational, or longitudinal--and regardless of the cultures tested in this study [East and West], you get the same effects," said Anderson. "And the effects are that exposure to violent video games increases the likelihood of aggressive behavior in both short-term and long-term contexts. Such exposure also increases aggressive thinking and aggressive affect, and decreases prosocial [sic] behavior."

Read the rest at:
http://news.yahoo.com/s/pcworld/20100303/tc_pcworld/itsconclusiveclaimsprofessorviolentvideogamesmakeusaggressive