Dahl and DellaVigna (2009) on Movie Violence and Crime

Gordon Dahl and Stefano DellaVigna, “Does Movie Violence Increase Violent Crime?” Quarterly Journal of Economics 124(2): 677-734, May, 2009 [pdf].

• Experimental evidence and survey responses indicate a rise in aggressive behavior after exposure to movie violence. Dahl and DellaVigna examine evidence from an ongoing “natural experiment,” seeing what happens to reported crime after a blockbuster violent movie.

• Assaults fall on the evening (both before and after midnight) that a violent movie attracts a large audience.

• For every million people watching a strongly violent or violent movie, assaults fall by more than 1% that night; after midnight, the fall is closer to 2%. A popular violent movie reduces assaults by about 1,000 per weekend. (Still, an unseasonably cold day would lead to an even greater fall.) 

• The mechanism seems to be that the criminogenic population selects into watching the movie rather than, say, drinking. Note that most movie houses do not serve alcohol. So for the evening of the movie watching, there is “voluntary incapacitation.” For the post-midnight hours, presumably there is a carry-on effect from the relatively salubrious hours in the cinema. 

• Even though violent movies reduce crime by enticing violence-prone individuals into the comparatively peaceful setting of a cinema, there would be an even further reduction in crime if these same people watched a non-violent movie. The laboratory evidence isn’t wrong, but it does not capture what appears to be the most important element of the movie violence-crime connection, the incapacitation of likely criminals as they watch movies. There is no evidence for an overall cathartic effect from watching violent movies.