Study: Men’s IQs Higher than Women’s

A large study by a British research team has concluded than men are slightly more intelligent, on average, than women but that geniuses are more than five times more likely to be male than female.

Is this a clever thing to say about women’s IQ? (Times of London)

Half the population will dismiss this story, but a study claims that the cleverest people are much more likely to be men than women. Men are more intelligent than women by about five IQ points on average, making them better suited for “tasks of high complexityâ€, according to the authors of a paper due to be published in the British Journal of Psychology.

Genetic differences in intelligence between the sexes helped to explain why many more men than women won Nobel Prizes or became chess grandmasters, the study by Paul Irwing and Professor Richard Lynn concluded. They showed that men outnumbered women in increasing numbers as intelligence levels rise. There were twice as many with IQ scores of 125, a level typical for people with first-class degrees. When scores rose to 155, a level associated with genius, there were 5.5 men for every woman.

Dr Irwing, a senior lecturer in organisational psychology at Manchester University, said that he was uncomfortable with the findings. But he added that the evidence was clear despite the insistence of many academics that there were “no meaningful sex differences†in levels of intelligence. “For personal reasons I would like to believe that men and women are equal, and broadly that’s true. But over a period of time the evidence in favour of biological factors has become stronger and stronger,†he said.

Philip Greenspun jokingly calls the research team the “Larry Summers of the U.K.” and observes that, “One challenge to this research is the fact that women do better in school than men, even at pretty high levels. Could it be that a slightly lower IQ helps people get A grades at top high schools and colleges? What would professors have to say about that?”

Jan Haugland dismisses this as “A study by – surprise – two male scholars” and points out that “most IQ tests are standardised to ensure the average IQ score for men and women is the same.” He cites a Wikipedia article:

Most IQ tests are designed so that the average IQs of males and females are equal. However, men tend to score higher in the parts of the test that cover spatial and quantitative abilities, and women generally score higher in the verbal sections. Some research has shown that the variance in men’s IQ scores is greater than the variance among women’s, as seen in other cognitive test scores. This would mean that men are more likely than women to have both very high and very low IQs.

Which makes sense. It would partly explain both the relatively higher number of male Nobel Prize winners and prison inmates.

The Wikipedia piece summarizes many of the key issues in the IQ debate, including tables showing the degree of correlation between IQ and various success indicators. It’s worth a look.

Update: BBC has more.

Atrios says that Lynn is a racist and advocate of genocide. If true–and I hate to take FAIR’s word for it–I’m not sure how that refutes the data. Either men score higher aggregate IQ scores or they don’t. Are there studies of comparable size that refute Lynn’s? Is there a major flaw in Lynn’s methodology? One can question whether IQ tests truly measure “intelligence,” of course, but that’s a separate argument.

Ann Althouse posits that, if the differences exist, they’re likely owing to enviromental factors rather than genetics.

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James Joyner
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James Joyner is Professor and Department Head of Security Studies at Marine Corps University's Command and Staff College. He's a former Army officer and Desert Storm veteran. Views expressed here are his own. Follow James on Twitter @DrJJoyner.


  1. Dave Schuler says:

    Honestly other than the titillation factor I don’t see why this has any significance at all. The difference, if it actually exists, is small—much less than a standard deviation—and not enough to explain the other marks of success noted in the quote. That small a factor could have any number of explanations and with human beings is there really a way to isolate the actual causes?

    Also, IIRC three standard deviations (over 145) is the genius level.

    Perhaps growing up in a family of super-brilliant women colors my judgement.