That story on sex differences in the brain, line by line

Screenshot 2014-07-29 at 13.00.42

So, let’s take it from the top:

Men’s and women’s brains really are different.

No they’re not. This study did not look at anybody’s brains, nor did it compare the brains of one sex to those of the other. The study recorded responses to quizzes.

Researchers say that if both sexes had access to the same levels of education, they’d expect women to do best on tests of memory – and men to excel at maths.

What the researchers actually say is: “We hypothesize that women benefit disproportionately from societal improvements [i.e. ‘access to the same levels of education’] because they may start from a more disadvantaged level.” In other words, the thrust of the finding is that equality of education helps to undo historically artificial sex differences.

The prediction comes after an analysis of how the sexes’ abilities varied across Europe across time.

Actually, the study compared cohorts of people born at different times. This is not “variation across time.” If you are better at Tweeting than your parents, this does not show that anybody’s performance at Twitter has “improved across time.”

More than 31,000 men and women aged 50-plus from 13 countries were put through three tests of brainpower.

The term ‘brainpower’ is figurative. The three very brief tests were not recognised IQ tests, nor did they involve any direct analysis of (biological) brain function. But, fair enough, insofar as (a) anything that involves people doing something involves them having the ‘power’ to do it, and (b) anything that involves life itself involves the brain, then you could loosely refer to this as ‘brainpower’.

The test of numeracy involved being given five questions, such as working out how much a cut-price car would have cost when new, while the memory test involved trying to remember a list of ten words.

That’s a fair description, but we need to bear in mind that these were not standardized aptitude tests. They might not measure what they want to.

The numeracy test involved four questions. First the participants were asked “If the chance of getting a disease is 10%, how many people out of 1000 would be expected to get the disease?” If that was answered correctly, the person was then asked “In a sale, a shop is selling all items at half price. Before the sale, a sofa costs 300 (local currency). How much will it cost in the sale?”. If that was answered correctly, the person was then asked “A second hand car dealer is selling a car for 6,000 (local currency). This is 2/3 of what it cost new. How much did the car cost new?” And finally, if that was answered correctly, the fourth and final question was put: “Let’s say you have 2,000 (local currency) in a savings account. The account earns 10% interest each year. How much would you have in the account at the end of 2 years?”

In my view this is more a screening measure of subnormal arithmetic ability. It’s a test of innumeracy rather than numeracy. If you get a low score on this test it probably means that you can’t count.

There is nothing in such a test to imply a sex difference in brain function. Any sex difference in scores would simply suggest a greater number of innumerate people in one group compared to the other.

If you know what this is, you're verbally fluent (Pic: -- go get it as a mural!)
If you know what this is, you’re verbally fluent
(Pic: — go get it as a mural!)

For the memory test, the participants were told “A little while ago, I read you a list of words and you repeated the ones you could remember. Please tell me any of the words you can remember now.”

And that was it. That was the so-called ‘episodic memory’ at which women are supposedly superior; the type of skill that being deprived of equal access to education has been suppressing all these years.

In my view, it’s a pretty poor measure of episodic memory. For one thing, it’s not even episodic memory.

The third test was of ‘verbal fluency’ – and involved naming as many different animals as possible in a minute.

There was no real finding for this, so we can leave it aside for now. (Although I note that the researchers counted as correct the mention of any animal at all, “real or mythical” — unicorns and ewoks included, I assume.)

In northern Europe, women in their 50s, 60s, 70s and 80s consistently outperformed the men in the memory test.

Actually no. Women did not “consistently outperform men.” It was a group-average difference, not consistent outperformance. Some women outperformed some men, but some men outperformed some women. It was just that the averages suggested that slightly more women outperformed men than the other way around. However, several thousand of the women were in fact outperformed by several thousand of the men.

You might expect a group of men to be, on average, slightly taller than a group of women. But you wouldn’t say that the men “were consistently taller” than the women.

However, in southern Europe, where economic conditions were poorer for longer, the earliest born women did worse than the men. However, as education and living conditions improved, so did their performance and those born from around 1940 onwards beat their male counterparts.

Bearing in mind the actual content of the ‘brainpower’ tests, what this suggests is that women born in southern Europe in the 1920s are less likely to remember those 10 words than women born in the 1950s. Maybe this is enhanced brain power. Or maybe 80-year-old women from Italy are more laid back than their younger counterparts when taking part in research studies. This type of cohort effect is a well known problem in research comparing older and younger adults. You don’t get to be 80 by getting wound up over word puzzles.

Men came out top in the maths tests in all countries at all ages.

Actually, what the researchers report is that the average score for men was a little bit higher than the average score for women. It is not in fact known whether the top scoring participant in any country was a man or a woman.

However, the gap narrowed as conditions improved, the journal Proceedings of the National Academy of Sciences reports.

Again, this is a cross-sectional study, so inferences about “conditions improving” — which suggests an effect across time — are unwarranted.

The researchers, from the International Institute for Applied Systems Analysis in Austria, said that women may benefit more than men from improvements in lifestyle because they were at a greater disadvantage to begin with.

This makes more sense than what was said earlier, in that it contradicts what was said earlier.

They said the patterns mean that if men and women had equal access to education, females should do better than men.

They didn’t really say that. They said that females should improve more than men because they were at a greater disadvantage to begin with.

Men should still to slightly better than maths [sic] – and the sexes should do equally well in quick fire tests of vocabulary.

The most that could be said is that some men might do better than some women at answering four particular questions about numbers. However: (a) this is not quite the same as saying that “men should do better,” because that implies that all men will do better than all women; (b) nobody knows if the four questions used in the study reflect real arithmetic ability or just four arbitrary questions; and (c) it’s all cross-sectional, so change over time cannot be inferred.

And, (d) it’s all correlational. Very correlational. For example, one of the key study variables is “years of education” which is found to predict numeracy. But because it’s correlational, the effect could just as likely be the other way around: it could just as easily be explained by the fact that being innumerate causes people to spend less time in school. They’re more likely to drop out, for one thing.

It is thought the differing strengths can be explained by differences in the biology of the brain as well as in the way the sexes are treated by society.

There is nothing in this study about “the biology of the brain.” These are cross-sectional correlations derived from patterns of responses given by 50-something-to-80-something-year-old Europeans to extremely brief pop-quizzes relating to 10-word lists, half-priced sofas, and “real or imaginary” animals.

No brains.


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  1. That was hilarious and an in-depth careful look at the article. It’s also a strange thing to say “[…] brains are different to […] minds”, isn’t it? Minds would be more about the function and brains about the underlying structure or activity etc.
    I’m myself fairly disappointed with the ways science frequently gets displayed in popular media, it often tells a story quite different from the original research.

    • Brian Hughes

      Thank you for that. Yep, “brains are different to minds” is a strange construction indeed. I’m thinking that the headline writer just wanted to use different words instead of repeating the word “brain” … for variety. So because something sounds better, it’s okay to change the meaning. Indeed, it’s okay for it to be meaningless.

  2. Brian Hughes

    Reblogged this on The Science Bit and commented:

    From the archives, and still relevant…

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