Pornography and rape

Everybody and their brother is sending me links to Steven Landsburg’s most recent Slate column that reports on studies by economists that suggest internet porn reduces rape and the release of blockbuster violent movies reduces violence.

While the idea might strike non-economists as crazy, the theory makes sense. When you lower the price of a good that is a substitute for a second good, the quantity of the second good should fall. It is not obvious that internet porn and rape are substitutes (they may very well be the opposite, what economists call complements), but it is not impossible.

I have to confess that Halloween with four young kids (a fairy, a witch, batman, and Dorothy from the Wizard of Oz) has been a full time job for the last week. So I haven’t read the academic articles. The paper on porn and rape was actually written by my former student Todd Kendall, now at Clemson. It is not really fair (especially to your former student) to be skeptical without reading the paper, but I have to say I am skeptical of the empirical result. The kind of variation in the data that gives the result is that states that are quicker to adopt the internet saw bigger declines in rape. He then does a nice thing in the paper, going beyond just this one prediction to test other hypotheses, like do crimes other than rape fall with the internet (he says no) and does other sexual behavior change with the internet (he says yes). The concern is always, with this kind of approach, that there are other factors that might be driving both the adoption of the internet and the decline in rape. The challenge to those who want to refute Todd Kendall’s argument is to identify those variables. The challenge for Todd is to find other kinds of “natural experiments” that support his hypothesis.

I suspect there will be no shortage of folks emailing Todd for his data to try to shoot his story down. A blog called 2x3x7 offers some thoughtful criticisms of the analysis.

By the way, Steven Landsburg, one of the kings of bringing economics to a broad audience, has an interesting new book coming out next year. I read an advance copy and enjoyed it.