Dumb Blondes and Athletes, smart brains...

Robert Frank has a nice piece in the New York Times (PDF here) describing some recent sociology/economics articles. Why are there so many jokes about dumb blondes and athletes despite persuasive evidence that blondes and athletes are no less intelligent than others? First the dumb blonde joke:

A married couple were awakened by a call at 2 a.m. The wife, a blonde, picked up the phone, listened a moment and said, “How should I know, that’s 200 miles from here!” and hung up. Her husband asked, “Who was that?” She replied, “I don’t know; some woman wanting to know if the coast is clear.”

Now the dumb athlete joke:

Two offensive linemen in a rented boat catch an unusually large number of trout in a secluded cove. As they start back to the marina, one reaches over with his felt-tip pen and marks an X on the starboard bow. “I want to make sure we can find this spot again tomorrow,” he explained. “Idiot,” his friend replied, “what makes you think we’ll get the same boat?”

Actually the hypothesis that beauty (blondness is viewed as a positive characteristic in women) and brains to together is more likely:

(1) men generally place relatively greater emphasis on looks; (2) women generally place relatively greater emphasis on income and status. (3) more-intelligent men tend to achieve higher income and status; (4) both intelligence and physical attractiveness are traits with significant inheritable components...if both beauty and intelligence are inheritable, then the offspring of such unions will tend to display above-average values of both traits.

So why the dumb blonde and athlete jokes?

If blondes are perceived as more attractive, then being blond may create valuable opportunities that do not require onerous investments in education and training. The dumb blonde stereotype may thus stem from the fact that blondes rationally choose to invest less than others in education and other forms of human capital.

and,

...because gifted athletes enjoy many attractive social and employment opportunities that others do not, they may rationally choose to invest less, on average, in human capital.

The bottom line is that popular perceptions about the intelligence of blondes and athletes may stem more from the academic choices made by members of these groups and from choices that others make about them than from any innate differences in mental ability.