BEAUTIFUL PEOPLE ARE MORE INTELLIGENT: PART 1
MAYBE BEAUTY ISN'T JUST SKIN-DEEP
By Satoshi Kanazawa
Psychology Today
March 29, 2009

Original Link

Sociologists and social psychologists have long known that there is a widespread perception shared by many people that physically attractive people are more intelligent and competent, as well as hold many other desirable characteristics. A large number of experiments over the years have shown that, when asked to rate the intelligence or competence of unknown others, people tend to rate attractive others as more intelligent and competent than unattractive others. This sentiment is captured in an old aphorism "What is beautiful is good." But why is this? Why do people believe that physically attractive people are more intelligent and competent?

While physical attractiveness is an integral part of mate selection, the evidence suggests that concerns for mate selection are not the reason people think that beautiful people are more intelligent. First, children as young as kindergarteners share the perception that beautiful people are more competent. Asked to choose between two teachers, one more physically attractive than the other, many kindergarteners prefer the more attractive teacher because they believe she is more competent and nicer. Second, more importantly, among adults, the common perception holds both within and between the sexes. Not only do men believe that more attractive women are more intelligent and women believe more attractive men are more intelligent, but men also believe that more attractive men are more intelligent and women also believe that more attractive women are more intelligent. Since 5-year-olds are typically not concerned with mate selection, and since most people are heterosexual, these two pieces of evidence suggest that there is more going on than concerns of mate selection.

Sociologists and social psychologists, convinced (and politically predisposed to believe) that "beauty is in the eye of the beholder" and "beauty is only skin-deep," dismiss this widespread perception as "bias," stereotype," or "halo effect," with the implicit assumption that the perception is not accurate and has no factual basis. It is a stereotype that beautiful people are more intelligent. But, as I explain in an earlier post, virtually all stereotypes are empirically true; if they were not true, they would not be stereotypes in the first place. And it turns out that this one is no exception. People believe beautiful people are more intelligent, because they in fact are.

The National Longitudinal Study of Adolescent Health (Add Health), conducted by a team of researchers at the University of North Carolina -- Chapel Hill, is one of the very few social science datasets that take biological and genetic influences on human behavior seriously. As a result, Add Health routinely measures both the intelligence and physical attractiveness of its respondents.

In the Wave III of Add Health, conducted in 2000-2001, respondents take an IQ test called the Peabody Picture Vocabulary Test. And then their physical attractiveness is measured objectively by an interviewer, who is unaware of their IQ test scores, on a 5-point scale (1 = Very unattractive, 2 = Unattractive, 3 = About average, 4 = Attractive, and 5 = Very attractive). The following graph shows the association between Add Health respondents' physical attractiveness and their intelligence. The data come from a large (n = 15,197) nationally representative sample of young Americans (mean age = 22).

Beauty and intelligence

As you can see, there is a clear monotonic positive association between physical attractiveness and intelligence. The more physically attractive Add Health respondents are, the more intelligent they are. The mean IQ is 94.2 for those rated "very unattractive," 94.9 for those rated "unattractive," 97.1 for those rated "about average," 100.3 for those rated "attractive," and 100.7 for those rated "very attractive." Due partly to the large sample size, the association is highly statistically significant.

As I explain in earlier posts, both intelligence and physical attractiveness are correlated with sex; men on average are slightly more intelligent than women, and women on average are physically more attractive than men. So it is important to see what the association between physical attractiveness and intelligence looks like within each sex. The following two graphs reproduce the association separately for each sex.

The graphs show that the association is no longer monotonic among either women or men, but the general positive association still holds for both sexes. "Very attractive" women are on average more intelligent than "very unattractive" women by about 6 IQ points. Similarly, "very attractive" men are on average more intelligent than "very unattractive" men by about 8 IQ points.

So it appears that the "stereotype" that beautiful people are more intelligent appears to be true empirically, just as virtually all "stereotypes" are. But now the question is: Why? Why are beautiful people more intelligent?

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BEAUTIFUL PEOPLE ARE MORE INTELLIGENT: Part 2
MAYBE BEAUTY ISN'T JUST SKIN-DEEP
By Satoshi Kanazawa
Psychology Today
April 5, 2009

Original Link

In my previous post, I explain that the reason people have the perception that beautiful people are more intelligent is that they indeed are. Just like virtually all "stereotypes," this "stereotype" has an empirical basis; beautiful people in fact are more intelligent. But now the important question is why. Why are beautiful people more intelligent?

There are two possible explanations for the observed positive association between intelligence and physical attractiveness. First, the evolutionary psychologist Geoffrey F. Miller suggests that there is a common source of variation between intelligence and physical attractiveness: the genetic quality of the individual which he calls the general fitness factor (the f factor). According to Miller's theory, those who have better-quality genes are simultaneously physically more attractive (because beauty is an indicator of health and genetic quality, as I explain in an earlier post) and more intelligent, hence the positive association between the two traits.

This is a very plausible theory, but I have doubts that it explains the association between intelligence and physical attractiveness. If Miller is correct, then the association between intelligence and physical attractiveness should disappear once genetic quality is controlled. At least in the Add Health sample, however, this does not appear to be the case. The positive association between intelligence and physical attractiveness is not at all attenuated when measures of genetic quality are controlled.

Alternatively, the association between intelligence and physical attractiveness may emerge from the process of assortative mating. If more intelligent men are more desirable to women than less intelligent men, because they achieve higher status, at least in the modern environment, and if physically more attractive women are more desirable to men than physically less attractive women, then there should be assortative mating of intelligent men and beautiful women, and of less intelligent men and less beautiful women. Because both intelligence and physical attractiveness are heritable, such assortative mating should create an extrinsic (non-causal) correlation between intelligence and physical attractiveness in the next generation. Children of intelligent men and attractive women should simultaneously be intelligent and beautiful, and children of less intelligent men and less attractive women should simultaneously be less intelligent and less attractive.

So which theory is correct? We don't know yet for sure. Available empirical evidence does support all crucial causal links in the second theory: More intelligent men do attain higher status than less intelligent men; higher-status men do marry more beautiful women than lower-status men; intelligence is heritable; and physical attractiveness is heritable. So there is some empirical evidence to support the second theory, but more research is necessary to adjudicate between the two theories. Or perhaps both theories are wrong and there is a third explanation for the association between intelligence and physical attractiveness. There is very little doubt that more beautiful people are indeed more intelligent, as the "stereotype" holds, but the proverbial jury is still out as to why this is so.