The rise of the Internet offers a gigantic natural experiment in the effect of pornography on crime, says Slate.com. The bottom line on experiments measuring use of the Net by state: “More Net access, less rape.” A 10 percent increase in Net access yields about a 7.3 percent decrease in reported rapes. States that adopted the Internet quickly saw the biggest declines. Clemson professor Todd Kendall says the effects remain even after you control for all of the obvious confounding variables, such as alcohol consumption, police presence, poverty and unemployment rates, population density, and so forth.
That’s a far cry from proving that porn access reduces rape. Maybe rape is down because the rapists are all indoors reading Slate or Wikipedia. Kendall notes there is no similar effect of Internet access on homicide. It’s easy to imagine how porn might serve as a substitute for rape. What happens when a particularly violent movie is released? Answer: Violent crime rates fall. Instantly. University of California professors Gordon Dahl and Stefano DellaVigna concluded that more violence on the screen means less violence in the streets. Probably that’s because violent criminals prefer violent movies, and as long as they’re at the movies, they’re not out causing mischief.