Are More Intelligent Men More Likely to Be Faithful? - Why More Intelligent Men (but Not More Intelligent Women) Value Sexual Exclusivity

The Intelligence Paradox: Why the Intelligent Choice Isn't Always the Smart One - Satoshi Kanazawa 2012

Are More Intelligent Men More Likely to Be Faithful?
Why More Intelligent Men (but Not More Intelligent Women) Value Sexual Exclusivity

Some tabloid newspapers have sensationally reported the above findings with such salacious headlines as “Cheat-on-Wives Men ’Less Intelligent’  ”14 (Metro), “Smart Men Less Likely than Dumb Ones to Cheat on Lovers: Study”15 (New York Daily News), and “Intelligent Men ’Less Likely to Cheat’  ”16 (Daily Telegraph). Apart from the sensationalism, and the confusion between “intelligent” and “smart,” which I address in Chapter 5, are these headlines correct? Do the data presented above suggest that more intelligent men are less likely to be sexually unfaithful to their wives and girlfriends?

Probably not. But before I can explain why not, and why more intelligent men are actually more likely to cheat, I need to make a small detour and discuss a very important concept in evolutionary biology called female choice.

Female Choice

Among all mammalian species (including humans) in which the female makes greater parental investment in children than the male does, sex and mating are a female choice, not a male choice.17 It happens whenever and with whomever the female wants, not whenever and with whomever the male wants. And humans are no exception.

A couple of studies brilliantly highlight the operation of female choice among humans. In a classic 1989 study, two social psychologists, Russell D. Clark and Elaine Hatfield, hired a young attractive confederate of each sex to approach college students of the opposite sex on campus.18 So a young attractive female confederate would approach a male student, or a young attractive male confederate would approach a female student, and say, “I have been noticing you around campus. I find you to be very attractive.” Then the confederate asked one of three questions: “Would you go out with me tonight?” “Would you come over to my apartment tonight?” and “Would you go to bed with me tonight?” The confederate would then simply record the subject's response (yes or no). They conducted the experiment twice, once in 1978 and again in 1982.

Here's what Clark and Hatfield found.

Unnumbered Table

There are two interesting findings here, although they are wholly unsurprising to anyone with common sense. First, both in 1978 and 1982, absolutely none of the dozens of women who were approached by a handsome strange man agreed to have sex with him. Second, an overwhelming majority of men (75% in 1978 and 69% in 1982) agreed to have sex with a beautiful strange woman whom they had never met before. Notice that a much smaller proportion of men (exactly 50% in both 1978 and 1982) would go out on a date with her. In other words, many men who would not go out on a date with the woman would nonetheless have sex with her! More women than men in 1978 and exactly as many women as men in 1982 were willing to go out on a date with the stranger, but none of the women would sleep with him.

This classic study was recently replicated in Denmark in 2009, even though the sex difference in the proportion saying “yes” (2% vs. 38%) is not as stark in the Danish study as it was in the original American study (0% vs. 75%).19 Interestingly, while none of the Danish women who were not currently in relationships said yes (just like their American counterparts), 4% of the women who were currently in relationships did. Given that the male confederates who approached them were physically attractive, this finding is actually consistent with the evolutionary psychological prediction from the Good Genes Sexual Selection Theory.20 It proposes that women seek to marry resourceful men of high status who would invest in their children (“dads”) while at the same time being impregnated by handsome men of high genetic quality (“cads”), and then to pass off the resultant children as their long-term mates’. The women cannot cuckold their mates unless they are already in a relationship, so it makes sense from this perspective that more women who are in relationships agreed to sleep with a handsome stranger.

Many of the men who said “No” in the original Clark and Hatfield study actually apologized to the female confederate, saying that they could not sleep with her because they were married or have a steady girlfriend, implying that they would have slept with her if they weren't married or didn't have a steady girlfriend. The Danish study indeed shows that men who were not currently in relationships were much more likely to say yes than men who were (59% vs. 18%). In contrast, many of the women were angry when the male confederate asked them if they would sleep with him.

The Clark and Hatfield study, like nothing else, demonstrates the power of female choice, which is why it has become a classic. It shows that a reasonably attractive young woman can approach any man and have sex with him. A reasonably attractive young man cannot with a woman. The woman decides when and with whom sex takes place; the man doesn’t.

Another study shows the continuing power of female choice. In an article published in the September 2008 issue of Obstetrics & Gynecology,21 Bliss Kaneshiro of the University of Hawaii and colleagues studied the effect of women's body mass index (BMI) on their sexual behavior. Their sample contained 3,600 women of “normal” body weight (BMI < 25), 1,643 “overweight” women (25 < BMI < 30), and 1,447 “obese” women (BMI > 30) between the ages of 15 and 44.

Their statistical analysis shows that there is no significant difference between normal-weight women, on the one hand, and overweight and obese women, on the other, on their sexual orientation, age at first intercourse, frequency of heterosexual intercourse, and the number of either lifetime or current male sexual partners. It means that, contrary to what one might expect, overweight and obese women are not having sex later, less frequently, or with fewer partners than normal-weight women. There is a significant difference, however, on whether they have ever had sexual intercourse with men. Overweight (92.5%) and obese (91.5%) women are significantly more likely ever to have had sexual intercourse with men than normal-weight women (87.4%).

Studies of mate preference throughout the world overwhelmingly show that men prefer to mate with women with low waist-to-hip ratios in the normal weight range.22 Men don't like women who are underweight, and men certainly don't like women who are overweight. So overweight and obese women could not possibly have as much sex as normal-weight women, let alone more sex, if men decide when and with whom to have sex. Most men would simply not choose overweight and obese women as their preferred sexual partners. Overweight and obese women can have more sex than normal-weight women only if women decide when and with whom to have sex, and men have little say in the matter.

When a man propositions a woman, she can respond in one of two ways; she can say “yes” or she can say “no.” When a woman propositions a man, he can also respond in one of two ways; he can say “yes” or he can say “yes, please.” He has no realistic choice to say no. Men may not be saying “yes, please” to overweight and obese women, but Kaneshiro et al.'s study clearly suggests that they are definitely saying “yes.”

Because of the power of female choice, every woman has the power to predict the future, while very few men do. If a man wakes up in the morning and says to himself, “Tonight I will get laid,” the prediction will fail a vast majority of times, unless he is incredibly handsome. Most young men in fact do make this prediction every morning and go to bed alone and disappointed every night. If a woman—any woman—wakes up in the morning and says to herself, “Tonight I will get laid,” the prediction will likely come true every time. Such is the power of female choice.

What Does Female Choice Mean for Intelligent Men's Preference for Sexual Exclusivity?

If sex and mating were an entirely or mostly male choice, and it happened whenever and with whomever men wanted, then it would be reasonable to conclude that more intelligent men, who value sexual exclusivity more than less intelligent men, may be less likely to be sexually unfaithful than less intelligent men. However, sex and mating are a female choice.

There are several complicating factors here. First, more intelligent individuals—both men and women—are more likely to attain higher status and accumulate more resources than less intelligent individuals, at least in the evolutionarily novel environment of today.23 And women prefer men of higher status and greater means as their mates.24 Second, more intelligent individuals—both men and women—are on average physically more attractive than less intelligent individuals.25

For example, in a recent study with the NCDS data, those who are described as “attractive” by two different judges are significantly more intelligent (IQ = 104.2) than those who are described as “unattractive” (IQ = 91.8), by 12.4 IQ points! The difference was much greater among boys (105.0 vs. 91.4) than among girls (103.6 vs. 92.3).26 In fact, by pure coincidence, intelligence in the NCDS data is just as strongly associated with physical attractiveness as it is with education; in both, the bivariate correlation coefficient is r = .381. Among other things, it means that, if you want to estimate someone's intelligence without giving them an IQ test, then you would do just as well to base your estimate on their physical attractiveness as you would to base it on their years of formal education!27

At any rate, women prefer handsome men as mates, particularly for short-term mating (“casual sex” or “affairs”).28 Third, general intelligence is strongly correlated with height; more intelligent individuals—both men and women—are significantly taller than less intelligent individuals.29 And, once again, women prefer taller men as mates.30

So, if you simply compare more intelligent men and less intelligent men, without statistically controlling for their social status, income, wealth, physical attractiveness, and height, I am almost certain that more intelligent men are more likely to have affairs than less intelligent men, not necessarily because they are more intelligent, but because they are more likely to have higher social status and greater resources, and to be physically more attractive and taller. If you partial out the effects of status, resources, physical attractiveness, height, and all the other potential confounds and correlates of general intelligence, then, and only then, may more intelligent men be less likely to have affairs.

However, to the best of my knowledge, no one has examined the partial effect of general intelligence on the probability of having affairs, net of all potential confounds. So we need further research in this area to determine what effect (if any) men's general intelligence has on their actual sexual behavior (extramarital or otherwise).

In fact, data from the GSS do suggest that more intelligent men (and women) are more likely to have affairs. The mean IQ of men who have had an extramarital affair is significantly (though only slightly) higher than that of men who have never had an extramarital affair (102.4 vs. 100.5). Among women, the difference is slightly larger (104.6 vs. 101.5).

Figure 7.2 Association between intelligence and having an affair among men


Figure 7.3 Association between intelligence and having an affair among women


The association between IQ and extramarital affairs remains significant, for both men and women, even after I control for education, income, and social class, as well as race, age, current marital status, number of children, religion, and religiosity. The effect of IQ is much stronger for women than for men. It is not clear to me why more intelligent women are more likely to have affairs than less intelligent women. Interestingly, as is quite often the case, intelligence and education have opposite effects on extramarital affairs for women. While more intelligent women are more likely to have affairs, more educated women are less likely to have them.

Unfortunately, the GSS does not measure the respondent's height or physical attractiveness, so I cannot control for them in the analysis. Add Health and NCDS, both of which do measure height and physical attractiveness, do not measure the respondents' experience of extramarital affairs. It therefore remains to be seen whether the significant association between intelligence and the propensity to have affairs among men is a function of the greater physical attractiveness and height of more intelligent men.

Note that the Intelligence Paradox is about individual preferences and values, what people desire and want in their heads; it's not necessarily about what people actually do. If people have complete choice over their behavior, they are expected to pursue what they desire and want, but they do not always have such complete choice. And, when it comes to sex and mating, men have very little choice.