Iowa State University researcher Dr. Doug Gentile studied 2,500 children and adolescents and found that violent video games do indeed foster hostile actions and aggressive behaviors. Here's the money quote:
We know a lot about how to be an effective teacher, and we know a lot about how to use technology to teach. Video games use many of these techniques and are highly effective teachers. So we shouldn't be surprised that violent video games can teach aggression.
Get the full story at the ISU News Service.