Do ultra-violent films like Saw and Hostel actually increase public safety?

And, if so, what is the implication for violent video games?

As reported by the New York Times, a pair of researchers have challenged traditional beliefs that violent films spur violent behavior. In a paper presented at the American Economic Association's annual meeting in New Orleans, Gordon Dahl (left) of the University of California at San Diego and Stefano DellaVigna of UC Berkeley concluded that potentially violent criminals are unable to harm others because they are safely tucked away in cineplexes instead. Said Dahl:

You’re taking a lot of violent people off the streets and putting them inside movie theaters. In the short run, if you take away violent movies, you’re going to increase violent crime.

Dahl and DellaVigna base their argument on crunching the numbers. They say that over the last 10 years, the showing of violent films has prevented about 1,000 assaults per weekend. 

Freakonomics at its finest?

Perhaps, but media violence researcher Craig Anderson of Iowa State University is skeptical:

There are hundreds of studies done by numerous research groups around the world that show that media violence exposure increases aggressive behavior. People learn from every experience in life, and that learning occurs at a very basic level of brain function.

Dahl and DellaVigna, however, do not attempt to refute past research on the effects of media violence, nor do they address the long term results of exposure to violent films. Instead, their research is tightly focused on the times during which violent films are shown and the periods immediately afterward. Said Dahl:

Economics is about choice. What would these people have done if they had not chosen to go and see a movie? Whatever they would have done would have had a greater tendency to involve alcohol. If you can incapacitate a large group of potentially violent people, that’s a good thing.

Melissa Henson of the Parents Television Council was concerned about how Dahl and DellaVigna's research might be interpreted:

The study’s premise strikes me as somewhat goofy. I’d hate for people to walk away with the message that, ‘Oh, I ought to send my son to watch violent movies so they won’t go out and drink or do drugs and commit violent crime.’ What about going to the Y.M.C.A. and playing basketball, or after-school activities?

What do the numbers say? From the NYT article:

From 6 p.m. to midnight on weekends — when the largest numbers of people are in theaters — violent crimes decreased 1.3 percent for every million people watching a strongly violent movie, the study found. Violent crimes dropped 1.1 percent for every million seeing a mildly violent film.

In the hours after theaters close — from midnight to 6 a.m. the next day — violent crimes dropped 1.9 percent for every million people at a strongly violent movie, and by 2.1 percent for every million at mildly violent film. Strikingly, the data shows that crimes also drop, though not by as much, when large audiences see nonviolent films that young men find appealing.

Dahl concludes that any movie - not just the violent type - which appeals to male teens and 20-somethings is likely to reduce bloodshed on the streets:

We need more Adam Sandler movies. Even though I’m not a big fan of Adam Sandler, that’s the implication.

GP: There is no mention of violent video games from Dahl and DellaVigna. We wonder, however, whether similar conclusions can be drawn. For example, will young males be inside playing Grand Theft Auto IV when it launches in April rather than finding trouble out on the streets?