At first, scientists wanted to know whether it was possible to read someone's intelligence from the shape of his face. In 1918, a researcher in Ohio showed a dozen photographic portraits of well-dressed children to a group of physicians and teachers, and asked the adults to rank the kids from smartest to dumbest. A couple of years later, a Pittsburgh psychologist ran a similar experiment using headshots of 69 employees from a department store. In both studies, seemingly naive guesses were compared to actual test scores, and turned out to be accurate more often than not.
Many such studies followed, and with consistent results: You can learn something about how smart someone is just by looking at a picture.
According to the abstract of the department store study, the correlation was 0.27, which is a pretty high correlation considering (1) the relative inaccurate grouping of IQ into only four categories, and (2) the people participating in the study were completely untrained in picking out the most and least intelligence. I think I could do better than 0.27.
However, I don’t buy into the theory that because of cross-assortative mating, the higher the IQ the better-looking, on average, the person. I think that reproductive fitness is highest at an IQ of 100-110, otherwise we would have evolved to have higher IQs. Above or below that level of IQ, attractiveness would decrease under my theory.
This is in response, or course, to the previous post in which I was trying to give some advice to some guy complaining that the women at Hopkins aren’t that attractive. I agree with commenters who say that part of the reason is that the Hopkins girls don’t dress slutty and don’t put forth the effort to wear makeup and bleach their hair and the various other things that less academically gifted young women are more likely to do to enhance their sexiness.
But I think the important message here is that people with high IQs look different, and I think there is some direct biological connection between physical appearance and intelligence that’s not just related to cross-assortative mating. This is further evidence that IQ is a biological trait.