The most recent state laws attempting to regulate the sale of violent games were overturned as unconstitutional, in large part because the states couldn't convince judges that exposure to violent games incited violent behavior in children. Had they been able to do so, a judge could have ruled that the government had a compelling interest in limiting the free speech protections afforded games, making such content-based laws constitutional.

　　But as long as politicians like Hillary Clinton and Sam Brownback continue to take the game industry to task for games like Manhunt 2, research on the effects of violent games on kids will be a hot-button topic for gaming advocates and detractors alike. The latest lightning rod in the debate is an article by University of Michigan professor L. Rowell Huesmann in a supplement to this month's Journal of Adolescent Health.

　　In a review of existing research titled "The Impact of Electronic Media Violence: Scientific Theory and Research," Huesmann presented findings from a variety of scientific papers published over the last 44 years (many of them his own). Ultimately, he concluded that there is compelling evidence to suggest exposure to violent TV programs, films, and video games increases the likelihood of a person acting violently, both in the short term and the long term.

　　One cited study tracked nearly 400 boys between the ages of 7 and 9 while they played floor hockey. Those who were shown a violent film beforehand committed more physical attacks (penalties) than those who were shown a nonviolent film.

　　For the long-term evidence, Huesmann pointed to a study of his that interviewed children over the course of three years in the '70s and "found increasing rates of aggression" for those who watched more violence on TV. A 15-year follow-up on the subjects of that study found that those who watched the most violent TV were more likely to have been convicted of a crime or to have abused their spouses.

　　"One valid remaining question is whether the size of this effect is large enough that one should consider it to be a public health threat," Huesmann said. "The answer seems to be yes." (Emphasis in the original.)

　　Finally, Huesmann compared the effect of media violence on aggressive behavior to the effects "of many other recognized threats to public health." He said the correlation between the two was nearly as strong as that between smoking and lung cancer, and stronger than the correlations between condom use and sexually transmitted HIV, exposure to lead and IQ scores in children, and homework and academic achievement.