Intelligence and Homosexuality - Why Homosexuals Are More Intelligent than Heterosexuals

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

Intelligence and Homosexuality
Why Homosexuals Are More Intelligent than Heterosexuals

Add Health

Add Health uses two different measures of homosexuality. The first question asks the respondents to identify their sexual orientation as either 1 = “100% heterosexual (straight),” 2 = “mostly heterosexual (straight), but somewhat attracted to people of your own sex,” 3 = “bisexual—that is, attracted to men and women equally,” 4 = “mostly homosexual (gay), but somewhat attracted to people of the opposite sex,” and 5 = “100% homosexual (gay).” This measure of sexual orientation corresponds to the “self-identified label” definition of it (1 above).

The analysis of Add Health data show that, even net of sex, age, race, marital status, parenthood, education, income, and religion, more intelligent children are more likely to identify themselves as homosexual in early adulthood than less intelligent children.20 The more intelligent Add Health respondents are in junior high and high school, the more homosexual they identify themselves to be in their 20s. The effect of childhood intelligence on adult homosexual identify does not differ for men and women.

Even though childhood intelligence and education are naturally positively associated (the more intelligent they are in childhood, the greater education they attain by early adulthood), intelligence and education have opposite effects on adult homosexual identity. While more intelligent individuals are more likely to identify themselves to be homosexual, the more educated individuals are less likely to do so.

Figure 9.1 represents the bivariate association between childhood intelligence and adult sexual identity. It shows that the association is monotonically positive; “very bright” children grow up to become more homosexual in their identity than “bright” children, who in turn grow up to become more homosexual than “normal” children, etc. The probability that one would observe a pattern as strong as the one depicted in Figure 9.1 purely by chance, when there is actually no association between childhood intelligence and adult sexual identity, is less than one in a hundred billion!

Figure 9.1 Association between childhood intelligence and adult sexual identity

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The second question asks, “Have you ever had a romantic attraction to a member of the same sex?” The respondents can answer either yes or no. This measure corresponds to the “self-reported sexual feelings” definition of sexual orientation (3 above).

The analysis of Add Health data shows that, net of the same factors as above, more intelligent children are more likely to have experienced adult homosexual attraction than less intelligent children.21 The more intelligent Add Health respondents are in junior high and high school, the more likely they are to have ever experienced romantic attraction to members of the same sex. If you increase childhood intelligence by 15 IQ points (one standard deviation), then you increase the odds of expressed adult homosexual attraction by 27%.

The effect of childhood intelligence on adult homosexual attraction is significantly stronger for women than for men. In fact, underscoring their more fluid sexuality,22 women have more than 50% greater odds of having ever experienced romantic attraction to members of the same sex than men do.

Figure 9.2 represents the bivariate association between childhood intelligence and expressed adult homosexual attraction. It shows that the association is monotonically positive. “Very bright” children are more likely ever to have experienced adult homosexual attraction than “bright” children, who are in turn more likely ever to have experienced it than “normal” children, etc. In fact, “very bright” children are nearly twice as likely to grow up to experience adult homosexual attraction as “very dull” children. The probability that one would observe a pattern as strong as the one depicted in Figure 9.2 purely by chance, when there is actually no association between childhood intelligence and expressed adult homosexual attraction, is less than one in 10,000.

Figure 9.2 Association between childhood intelligence and expressed adult homosexual attraction

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GSS

While Add Health has precise measures of homosexual identity and feelings (corresponding to 1 and 3 in the list of definitions of sexual orientation above), it unfortunately lacks any measure of actual sexual behavior with members of the same sex; it only measures heterosexual sexual behavior. I therefore now turn to the GSS, which measures both homosexual and heterosexual behavior.

The GSS measures the respondents’ homosexual and heterosexual behavior by asking how many sex partners of each sex they have ever had since they were 18. This measure of sexual orientation corresponds to the “actual sexual behavior” definition of it (2 in the above list).

The analysis of the GSS data shows that, consistent with the Intelligence Paradox, net of sex, age, race, social class, education, income, marital status, number of children, religion, and survey year, more intelligent individuals have more homosexual partners in their adult life than less intelligent individuals.23 Contrary to the prediction of the Intelligence Paradox, the GSS data also show that, net of the same control variables, more intelligent individuals have more heterosexual partners in their adult life as well than less intelligent individuals.

However, the effect of intelligence on the number of homosexual partners is twice as strong as its effect on the number of heterosexual partners. As Figures 9.3 and 9.4 below show, “very bright” Americans have had eight times as many homosexual partners as “very dull” Americans (2.42 vs. .31). In sharp contrast, “very bright” Americans have had less than 40% more heterosexual partners than “very dull” Americans (9.79 vs. 7.10). In fact, “bright” Americans have had more heterosexual partners (9.98) than “very bright” Americans.

Figure 9.3 Association between intelligence and the lifetime number of homosexual partners

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Figure 9.4 Association between intelligence and the lifetime number of heterosexual partners

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NCDS

Add Health and GSS very precisely measure homosexuality by the three more malleable, less stable definitions of sexual orientation (1, 2, and 3 in the list above). And the data show that all three measures of homosexuality are significantly positively associated with intelligence. The more intelligent the individuals, the more homosexual they are, even net of a large number of potential confounds and correlates of intelligence.

However, Add Health and GSS have one small problem, as I mention in the Introduction when I discuss the details of the data sets. Both Add Health and GSS have measures of verbal intelligence, not general intelligence. While verbal intelligence is very strongly and significantly correlated with general intelligence—in fact, it is an important component of general intelligence—it is not exactly the same as general intelligence. NCDS rectifies this problem, as it has a very good and highly reliable measure of general intelligence, assessed by 11 cognitive tests administered at three different ages.

Unfortunately, the only measure of sexual orientation that NCDS has is the number and sex of cohabitation partners. At age 47, NCDS asks its respondents how many same-sex and opposite-sex cohabitation partners they have had, defined as someone with whom the respondents have lived “as married” and shared an accommodation for six months or longer.

Using this measure of sexual orientation, the analysis of the NCDS data show that more intelligent children (before the age of 16) have significantly more lifetime homosexual cohabitation partners 30 years later than less intelligent children, even after statistically controlling for sex, whether currently married, whether ever married, whether ever a parent, education, income, and religion.24 In sharp contrast, childhood general intelligence is not at all associated with the lifetime number of heterosexual partners. Since heterosexual cohabitation is eminently evolutionarily familiar, this is once again perfectly consistent with the prediction of the Intelligence Paradox.

The analyses of all three data sets (Add Health, GSS, and NCDS) uniformly confirm the prediction of the Intelligence Paradox. More intelligent children are more likely to grow up to identify themselves as homosexual and to have ever experienced romantic attraction to members of the same sex. More intelligent individuals have had more lifetime homosexual sex partners than less intelligent individuals (although intelligence is also associated with the lifetime number of heterosexual partners). More intelligent children grow up to have a larger number of lifetime homosexual cohabitation partners 30 years later, but childhood general intelligence does not predict the lifetime number of heterosexual partners. The positive association between intelligence and homosexuality appears to be quite strong and robust.

Notes

1. Bagemihl (2000); de Waal (1995)

2. Kirk et al. (2000)

3. Bailey and Pillard (1991)

4. Ellis and Ames (1987)

5. Blanchard and Bogaert (1996a); Bogaert (2003)

6. Mustanski, Chivers and Bailey (2002); Wilson and Rahman (2005)

7. Bailey (2009); Chivers et al. (2004); Diamond (2008)

8. Mustanski et al. (2002, pp. 122—127); Wilson and Rahman (2005, pp. 13—16)

9. Adams, Wright and Lohr (1996)

10. Wilson and Rahman (2005, p. 15)

11. Chivers, Seto and Blanchard (2007)

12. Hamer et al. (1993); Turner (1996a)

13. Levinson (1991—1995)

14. Levinson (1991—1995, Volume 2, p. 79)

15. Levinson (1991—1995, Volume 2, p. 285)

16. Chagnon (1992); Cronk (2004); Hill and Hurtado (1996); Lee (1979); Whitten (1976)

17. Hill and Hurtado (1996, pp. 276—277; emphasis added)

18. Hill and Hurtado (1996, p. 277)

19. Blanchard and Bogaert (1996b); Bogaert and Blanchard (1996)

20. Kanazawa (Forthcoming)

21. Kanazawa (Forthcoming)

22. Diamond (2008)

23. Kanazawa (Forthcoming)

24. Kanazawa (Forthcoming)