The school massacre in Newtown, Conn., has renewed discussions -- and perennial disagreements -- among politicians and researchers about how violent movies and video games affect the nation's youth.
On Friday, children in Newtown pledged to throw away video games containing violent scenes in a movement they called "Played Out: Choose Not to Play."
Motion Picture Association of America Chairman Chris Dodd, who represented Connecticut in Congress for 36 years, this week said his industry colleagues felt "horror and outrage at this senseless act of violence" and promised to participate in White House discussions of how to respond to the slaughter of 26 children and adults at Sandy Hook Elementary School.
"Those of us in the motion picture and television industry want to do our part to help America heal," said Dodd, a former U.S. senator and representative. "We stand ready to be part of the national conversation."
Hollywood canceled or postponed the release of several violent films and television shows, including the scheduled premiere of director Quentin Tarantino's ultra-violent film "Django Unchained" and the Tom Cruise action-packed "Jack Reacher."
Sen. Jay Rockefeller, D-W.Va., this week called upon the National Academy of Sciences to conduct a new federal study into "the impact of violent video games and other (media) content on children's well-being."
The video-game industry reports that recently released shooter-style games such as "Halo 4" and "Call of Duty: Black Ops II" helped propel worldwide sales to an estimated $4 billion last month, although that figure is down from Christmas-time sales in recent years.
"At times like this, we need to take a comprehensive look at all the ways we can keep our kids safe," Rockefeller said. "I have long expressed concern about the impact of the violent content our kids see and interact with every day."
Connecticut Sen. Joe Lieberman said teenage boys and young men who commit mass murder often have "an almost hypnotic involvement in some form of violence in our entertainment culture, particularly violent video games."
Police have not confirmed whether the shooter, Adam Lanza, played such games before fatally shooting 27 people, including his mother, Nancy Lanza, and then killing himself.
Researchers who've studied the issue are almost as violently divided as the games and films they monitor.
"Violent video games increase aggressive thoughts through physiological arousal," concluded Brad Bushman, a professor of mass communication at The Ohio State University. "People who have aggressive thoughts are much more likely to have aggressive behavior. This makes people numb to the pain and suffering of others."
Bushman was one of eight scholars from the United States and Japan who published an analysis in 2010 of dozens of studies conducted around the world into the effects of violent games on behavior.
"Concerning public policy, we believe that debates can and should finally move beyond the simple question of whether violent video game play is a causal risk factor for aggressive behavior," the scholars concluded. "The scientific literature has effectively and clearly shown the answer to be 'yes.' "
Instead, they wrote, the public debate "should move to question concerning how best to deal with this risk factor."
But Chris Ferguson at the Texas A&M University's Department of Behavioral, Applied Sciences and Criminal Justice warns that Bushman and his colleagues should not be so quick to declare what science as learned.
"Brad's study was not a very good one," Ferguson said. "There was a selection bias. He and his colleagues didn't include many studies that did not find any effects from violent media."
Ferguson led a review of other scientific studies that he published in 2009 in the Journal of Pediatrics, determining that "results from the current analysis do not support the conclusion that media violence leads to aggressive behavior. It cannot be concluded at this time that media violence presents a significant public health risk."
Ferguson and Bushman have talked about the issue over which they hold diametrically opposed findings.
"I know Brad very well," Ferguson said. "We tend to be very friendly, as long as we don't talk about video games."
Meanwhile, the head of the National Rifle Association, Wayne LaPierre, on Friday blamed video games rather than the availability of assault-style weapons for the shooting rampage in Connecticut.
"Here's another dirty little truth that the media try their best to conceal: There exists in this country a callous, corrupt and corrupting shadow industry that sells, and sows, violence against its own people," LaPierre said.
He blamed "vicious, violent video games" like "Bulletstorm," "Mortal Kombat" and "Splatterhouse" as well as "blood-soaked slasher films" like "American Psycho" and "Natural Born Killers."
"In a race to the bottom, media conglomerates compete with one another to shock, violate and offend every standard of civilized society by bringing an ever-more-toxic mix of reckless behavior and criminal cruelty into our homes," LaPierre said.