Cognitive Differences Between the Sexes: a Question Worth Asking

by Isobel Marston

Essay originally from Counterweight.

The question of whether or not there are biologically based psychological and cognitive differences between the sexes is a touchy subject in much feminist literature and increasingly—as these ideas have by now far outgrown the confines of academia—society at large. Judith Butler has gone so far as to say that sex itself is a social construct that has “no ontological status” beyond our social realities; that is, the significance of sex is socially constructed in the way we classify it. Others argue for the weaker claim that only gender is a social construct. Typically speaking, sex is thought of as one’s biology—as determined by the chromosomes one possesses and the ways in which one’s body is made up to aid sexual reproduction—and gender as the social expression or psychological traits that are typically associated with a particular sex.

Suspicion of psychological and intellectual differences between the sexes is understandable when placed in its historical context. It was not so long ago (and is still the case in many parts of the world today—as well as in many pockets of societies that have come far in gender equality) that females were thought of as inherently subservient, irrational, intellectually subpar and generally inferior to men. A lot of these ideas and stereotypes were dubiously justified by purported biological realities and used to keep women out of fields and jobs they were deemed incapable of succeeding in. It is not surprising, then, that to some the women’s liberatory project seems to necessitate demonstrating the falsity of these ideas and stereotypes by denying biologically based gender differences between the sexes and showing these differences, or ideas of differences, to be the product of socialisation. This does not have to include a Butler-esque radical suspicion of the biological categories of male and female; it merely requires a denial that such biological differences play a significant role in gender differences.

While this route is an understandable one, it can go too far. That is, if women’s liberation is deemed to only be achievable by eradicating stereotypes, one may be tempted to conclude that this involves demonstrating that women are identical to men in all ways—and that anyone who says otherwise is morally suspect or bigoted. However, from the correct claim that some ideas regarding gender differences and actual gender differences have been the product of misinformation and socialisation it does not follow that all ideas regarding gender differences and actual gender differences are the result of misinformation and socialisation. Indeed, given the years of evolutionary history that have produced the sexually dimorphic species that we are today, it would be quite startling if there were no differences in personality traits, interests, intellectual capabilities etc. between the sexes. Our cognitive and psychological traits, after all, are not under the remit of some immaterial Cartesian substance, but our physical brains.

The notion that anyone who doubts parity across all cognitive and psychological domains of the sexes is merely serving to reinforce, or reintroduce, ungrounded stereotypes we would be better off without, is misguided. Acknowledging differences between the sexes does not constitute or necessitate the disempowerment of one sex in favour of the other; in fact, I think a reasonable case can be made that—in our current times—the denial of genuine differences can send unnecessarily disempowering messages to women.

But figuring out exactly what these differences are, the degree to which they affect real world differential outcomes and the causes of these differences is much easier said than done.

Take IQ for example. With the proliferation of podcasters in recent years, I have found myself accessing ideas and thinkers through a medium I am unused to in the form of videos or recordings. As an avid book reader with a lot of love for the written word and less, so I thought, for the spoken one, my steps into this world were tentative. However, I found myself becoming enamoured with certain thinkers and speakers for their eloquence and wit in the face of situations and intellectual challenges which would have most stammering and red-faced. Watching people who surely fit the bill of “brilliance”—I am thinking here of the likes of the late Christopher Hitchens and, for people closer to my own age, Coleman Hughes and Alex O’Connor—can be something of an awe-inspiring experience and it filled me with a keen, but clearly unrealisable, desire to emulate.

For me, sometimes compounding this sense that emulation was unlikely was the realisation that not all, but almost all, of those I most admired and who filled me with that sense of awe tended to be men. There are of course many brilliant and awe-inspiring women, some of whom are in our Counterweight staff; however, the overwhelming majority of those who seemed to fit the bill of intellectual brilliance had or have an appendage that I lack. This became increasingly apparent to me once I had started accessing more and more ideas through YouTube. In reading, one is less inclined to notice the sex of the author – and therefore less inclined to ponder over their lack of appendage and whether such a state of affairs constitutes a hindrance in intellectual progression.

I started to worry if this might be caused by my own sexism. In conversations with a friend, we had both acknowledged that the really smart people we have met or looked up to tend to be men. Perhaps, though, it just seemed this way to us? Maybe we simply perceive men as smarter. Or maybe brilliant women just get less attention in general. Perhaps we are less likely to buy the books of brilliant women, listen to the podcasts of brilliant women, or invite brilliant women to debates. Perhaps we, as a society, really do have deeply ingrained biases that affected both my perception of the relative intelligence of the most intelligent men and women and the ability of brilliant women to progress.

These thoughts are quite depressing. I have always thought that men and women were of equal intelligence; both my parents have doctorates in STEM and I have precious little experience of people treating me as inferior, or assuming a lesser intelligence, due to my sex. However, the creeping suspicion started that I would never be like my heroes. This, of course, is probably true for almost everyone regardless of their sex. However, it stings a bit more when it seems like this is not the result of sheer statistical unlikelihood but the hobbling inflicted on my sex by a potentially unfair and biased society. A prejudice, in fact, that works so effectively I seemed to be sexist myself despite holding no conscious ideas of IQ differences between the sexes.

At first light, articles and research seem to support this depressing narrative; that is, that women, despite being equally capable, are not considered to be as brilliant as men. For example, in an article titled ‘We Are Biased to Think Men Are Smarter, and That Hurts Women, the author writes (referring to a study on gender bias):

“The odds of referring a woman were 38.3 percent lower when the job description mentioned brilliance,” the researchers report. This same bias was found whether the person making the recommendation was male or female. …

By many metrics, women are equal, if not superior, to men in the intellectual arena. “Girls make up over half of the children in gifted and talented programs,” the researchers note. “Women graduate from college at higher rates, as well as from master’s and doctoral programs.”

Yet the underlying prejudice persists. (It helps explain why children still think of scientists as male.) That means some of our smartest citizens are not getting the opportunities they deserve, which ultimately hurts everyone.

Bian and her colleagues point to two possible ways to fight this bias: “By changing the brilliance=men stereotype, or by making this stereotype irrelevant to decisions about employment.”

From another article, discussing a study on gender stereotypes:

“Overall, STEM fields are more likely to endorse the belief that you have to be brilliant to succeed,” he [Andrei Cimpian, the study co-author] says. “But there’s variation among the STEM fields, and that variation tracks with their diversity.” A 2015 study co-authored by Cimpian found that while women were earning around half of all PhDs in fields such as molecular biology and neuroscience, less than 20% of women were earning PhDs in physics and computer science, two disciplines commonly associated with “brilliance.” By contrast, around 70% of all PhDs in the humanities such as art history and psychology were earned by women at the time.


These articles and studies all seem to point towards the same conclusion: women are unfairly considered to be less brilliant than men. So, on the brink of denouncing all of western society and lamenting the unfairness imposed on me by drawing the short end of the stick of our species’ sexual dimorphism—why could I not be a clownfish?!—I came across some interesting information. There is a question in need of answering which is suspiciously lacking from consideration in these articles: are there differences between men and women when it comes to the very top end of the IQ distribution? The answer seems to be yes. While research tends to show that average IQ differences between men and women are non-existent or small—indeed, IQ tests are usually constructed so that there are no questions that advantage men over women and vice versa—there seem to be large differences between the sexes when it comes to IQ distributions. Namely, there are far more men on the extreme top end of the IQ distribution as well as the extreme low end of the IQ distribution. This means that, yes, there are more brilliant men—if we define brilliance in terms of exceptionally high IQs. However, it seems that there are more significant differences at the low end of the IQ distributions than at the high end. There is a decent amount of evidence in favour of this. See here, here, here, here and here for studies that seem to confirm the male variability hypothesis—the hypothesis that males show more variability than females in certain traits. Two of these studies are very large cross-cultural meta-analyses. Another includes two Scottish population samples of 11-year-olds, one containing around 71,000 children and the other 81,000 children. Another is a 30-year study with 1,173,350 test scores ranging over 20 years for SAT-mathematical ability and 440,369 test scores ranging over 30 years for ACT-mathematics and ACT-science.

So, is it settled? Is the male variability hypothesis confirmed and can we finally put to rest the question of biological or genetic cognitive differences between men and women? Alas, probably not. It is clear that males are more variable than females in some countries. However, disentangling nature from nurture is an often-impossible task, and it is not yet clear the degree to which these IQ differences are the product of genetic variability that is perhaps greater in men due to how they evolved for sexual competition or environmental and social factors. Indeed, it often makes little sense to pose the question as an either-or in the first place. The nature versus nurture debate is almost always a false dichotomy—the development of organisms is not so neat or easily divided into broad categories of biology versus environment. Further, the biological is indeed malleable. And, for all the countries that show homogenous findings of greater male variability, there are still some, albeit fewer, countries that some studies have found to be neutral in regards to male and female variability in IQ, and even countries that show greater female variability. Further, male variability seems to shrink to an extent as societies progress with gender equality, suggesting that IQ differences are not the sole product of genetics.

There is some conflicting information regarding the degree to which male variability tracks gender equality. One meta-analysis finds that mathematical variability correlates with gender equity measures, another meta-analysis finds that higher male variability is almost universal in countries with comparable assessments and another study finds that the shrinking of the male to female advantage in the very top end of mathematical ability (top 5%) has pretty much stopped within the last two decades. That is, it shrunk rapidly when many barriers in the way of women were taken away, and then plateaued.

Why do I always admire smart men, then? Is it because there are more men with exceptionally high IQs, and is this only a reality due to a prejudiced society, or is it the result of genetics, or, more likely, some combination of the two? Or perhaps it has less to do with IQ and more to do with average lower neuroticism in men and average increased aggression in men, helping them make it to the top of their professions in extremely competitive markets. Or perhaps it really is the result of prejudice and discrimination. In all honesty, I am unsure, and I am not convinced we have the data that will conclusively settle these issues. What I do think, however, is that finding out is important. And that these issues are unnecessarily polarised given the importance of the answers on the functioning of our society and given the fact that working out the data and sifting through the studies is genuinely hard. It will not do, for example, to fire or pressure to resign, those with whom we disagree on this topic.

Imagine, for example, that it is the case that men are genetically more variable than women, leading to far more men on the top end of the IQ scale. If we ignore this, demonise those who research it or simply suggest it as a possibility, what happens? What is the cost of viewing all disparities between the sexes as a result of bias and prejudice if they are not? Without heavy social manipulation, we will never see perfectly equitable outcomes. This means that fields in which men tend to excel will always be viewed as sexist even in a hypothetically perfect utopia of meritocracy. What does it say to a young female mathematician who is, herself, brilliant, that she will likely be received badly in the academic world, that she will be falsely perceived as less smart than those with whom she has comparable or superior ability, that she will likely fail to progress and not be suited for jobs for which she is perfectly capable? When we ignore differences in capability, we convince those who are capable that they will not be perceived as such. We bolster the view of those who are not, and never were, capable that failures are the fault of bias rather than the genetic lottery.

It is important to note that the current evidence supporting differences between the sexes at the top end of the IQ distributions does not entail that all differences of representation in academically demanding jobs are the result of these differences. Further, it does not entail that woman are always perceived as less brilliant because they are less brilliant. Even stereotypes that have at least some bases in reality are still stereotypes which are essentially shortcuts that are often wrongly applied to, and affect our perception of, those who do not fit them. Further, there is a very large degree of overlap between the sexes and certainly a lot of women with high IQs. The differences we are seeing are, at the risk of repeating myself, at the very top end of the IQ distribution which means that the majority of men and women will not be impacted in the least by these differences.

On the other hand, let’s say that greater male variability is the primary product of socialisation. First, this would not negate the importance of taking into account current differences in the IQ distribution: it would not help, for example, to force equitable outcomes at high levels if there are not enough women to successfully compete at those levels – regardless of what caused this skew. Instead, research would need to be done to determine how exactly these different distributions are coming about and what could be done to reduce them in the long term.

We must, then, be cautious of four things. One, of suppressing or denying truths that are socially unpopular, the effects of which will always play out in differential outcomes in the real world yet distort our ability to effectively deal with, and interpret, them—to the ultimate disservice of women. Two, of utilising these truths to lazily justify all differential outcomes or to ignore the effects of bias and prejudice that can result from wrongly applying knowledge of the existence of differences in IQ distribution to the individuals in front of us who should only be assessed on their individual capabilities. Third, of conflating differences in IQ distribution with proof of genetic differences between men and women. And fourth, of trying to solve complex problems with surface solutions like forced equitable outcomes.

We could all do with stepping outside of our echo-chambers when it comes to matters such as these which are prone to politicisation from both sides of the spectrum. Whether your echo-chamber more closely resembles publications like the Guardian, the “intellectual dark web”, or something more right wing, the likelihood is you are getting an incomplete picture of the issues at hand packaged up to look neater and more conclusive than the data would allow you to be.

Isobel Marston is Counterweight’s Content Coordinator & a student of philosophy at the University of Southampton.

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