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Sex and IQ? Don't Ask: We don't Want to Know!

IQ tests habitually hide sex differences in cognition, but they are real.

C. Badcock
Source: C. Badcock

In a previous post, I drew attention to modern prudery about the reality of sex differences understood in terms of personal costs and benefits. But cognitive differences between the sexes are no less important, and here as elsewhere present-day PC prudishness shows itself in an attempt to conceal the truth.

The first, and in many ways most important fact—and one that may surprise many readers as it did me when I first found out about it—is that items showing large sex differences are always omitted from IQ tests such as the widely-used Wechsler. The result, of course, is that standard measures of IQ systematically obscure sex differences in intelligence—despite the fact that Wechsler himself commented that he had a “sneaking suspicion that the female of the species is not only more deadly than the male, but also more intelligent.”

But however that may be, males averagely do better in tests of mathematical reasoning (especially geometry and logic); embedded-figure tasks; target-directed motor skills (irrespective of practice); and some—but not all—spatial skills. For example, in tests of ability to visualize spatial rotation, men perform better than women, and although brain injury degrades performance of both sexes equally, testosterone greatly improves female performance. Boys always win the National Geography Bee (which tests children grades 4-8 in US schools on knowledge of places), and at college, male students can locate twice as many countries on unlabelled maps as can females. IQ tests omit items on mechanical comprehension, but US Air Force tests show a male effect size of 0.95 for this ability (which means that the average male performs better than about 80% of females).

In comparison, females are averagely superior to males in tests of social judgment; empathy and co-operation; language skills (such as finding synonyms, where the average woman can name twice as many as the average man); perceptual speed (for example, finding matching items); fine-motor co-ordination; pretend play in childhood; and arithmetic. More generally, women exceed men in facial expressiveness, interpretive skill, gazing, smiling, and expressiveness of body language. A meta-analysis of many studies concluded that women also exceed men on measures of anxiety, trust, tender-mindedness and gregariousness, whereas men exceed women on assertiveness—a difference which is invariant across ages, educational levels, and nations. According to another meta-analysis, men are more aggressive and restless, are more likely to lead groups, and to contribute more in small groups. Women, by contrast, make greater social and emotional contributions to groups and are more easily influenced by them. Universally, women are also more religious than men (when they are allowed to be), are less likely to take risks and indulge in violence, and have superior ability to inhibit their impulses.

Although routinely denied, disputed, and disparaged, these findings are important because they suggest that male and female cognitive abilities may not have evolved in exactly the same way and that the two fundamental modes of cognitionmentalistic and mechanistic—are also relevant to sex differences, with males being more mechanistic and females more mentalistic (and indeed even hyper-mentalistic where the issue of religion is concerned). This would immediately explain the findings set out above as well as the cleverly-concealed sex differences in intelligence.

Female intelligence, to put it simply, is more mentalistic in quality thanks to women’s greater degree of parental investment in particular and social adaptation in general. Men, by contrast, turn out less mentalistic thanks to their lower levels of parental investment but much higher degree of mating effort (the 10-times-married-man-having-10-times-more-children-than-a-10-times-married-woman effect I mentioned in a previous post). In our primal hunter-gatherer past, this would have amounted to a mechanistic kind of intelligence more concerned with hunting, fighting, competing with other males, and manufacturing the weapons and tools appropriate to these activities. Men, to put it shortly, have minds more concerned with things, women have mentalities more related to people, and the difference shows in cognitive tests, whatever the testers may have wanted you to think.

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