Sex differences in the brain

For a while I’ve been criticizing ideologically-based scientific claims, including the arguments that “evolutionary psychology is bunk” and “there are no differences between male and female brains in either structure or wiring”. These claims are based on ideology because both are palpably ridiculous from what we know about biology or from recently published research, and yet people maintain them because they want the brain to be a blank slate and they want there to be no average differences between men and women in brain structure and function. These wants come from left-wing ideology.

Although these claims are ideological and not scientific, they are based on a well-meaning philosophy: the view that people should be treated fairly and given equal opportunities. But this has engendered the fears that distort the science:  a fear that if we’re not blank slates, but that sexes and different ethnic groups differ genetically—perhaps in part because of evolution—then that would somehow justify misogyny and racism.

I don’t think that follows at all, since equality is a moral stand that is independent of biology. Making equality somehow contingent on biology, whether we be all biologically identical or not, has the unpalatable consequence that your stand on equality is malleable in view of new findings in biology.

In fact, the same people who unjustifiably deny sex differences in brain and behavior also call for medical researchers to take into account sex differences in the body, for the choice and efficacy of different treatments often depend on sex. And so, as I say—in league with Robert King, a psychologist at University College Cork—that yes, there are differences on average between the behavior and the brains of men and women, and no, that should not justify sexism in any way. After all, why should evolution have differentiated sexes from the neck down (a differentiation based in part on sexual selection), but left what’s above the neck the same? Sexual selection, after all, creates sex differences in behavior, and those are mediated through the brain:

Here’s King’s new piece in Psychology Today (click on screenshot):

One of the biggest proponents of the “no brain/behavior differences between men and women” has been the Aussie-British philosopher Cordelia Fine. King wrote a fair but critical review of her latest book, Testosterone Rex, in Quillette.  Fine’s ideological “no difference” view has recently been buttressed by a new book by Gina Rippon that I recently highlighted: (note: I’ve read Fine’s books but haven’t read Rippon’s yet since it’s not available in the US):

The same problems that plagued Fine’s books now appear to resurface in a new book by Gina Rippon that makes the same “no-difference-in-brains” claim: The Gendered Brain: The New Neuroscience that Shatters the Myth of the Female Brain, recently out in the UK and soon to be released in the US under the title Gender and Our Brains: How New Neuroscience Explodes the Myths of the Male and Female Minds. Wikipedia describes Rippon as “professor of cognitive neuroimaging at the Aston Brain Centre, Aston University, Birmingham.”

Rippon’s book got extremely favorable reviews in Nature and The Guardian, with both reviews being almost embarrassing in their complete failure to deal with existing data (see below) and the insupportable claim that every difference between male and female brains and behavior can be ascribed to plasticity, social conditioning, and our “gendered world.” King notes, however, that two researchers (both women) wrote a strong critique of the lame book-review in Nature. I’ll add that Nature doesn’t usually publish rebuttals of book reviews (click on the screenshot):

Much of the review:

We are concerned that Lise Eliot’s review of Gina Rippon’s book The Gendered Brain (Nature 566, 453–454; 2019) undermines the premise that sex is a biological variable with respect to many medical conditions and drug responses (see J. A. Clayton and F. S. Collins Nature 509, 282–283; 2014).

As president-elect and president, respectively, of the Organization for the Study of Sex Differences, we disagree with Eliot’s claim that the brain is “no more gendered than the liver or kidneys or heart”. We also disagree that sex differences in behaviour are due to cultural effects on newborns, not to biological effects. In our view, these are not mutually exclusive. Sex disparities occur in animal models that are not subject to cultural bias.

The brain, like many organs, shows differences attributable to sex, both during health (see, for example, E. Luders et al. J. Neurosci. 29, 14265–14270; 2009) and during disease. Two-thirds of people with Alzheimer’s disease are women; twice as many men as women have Parkinson’s disease (see, for example, L. J. Young and D. W. Pfaff Front. Neuroendocrinol.35, 253–254; 2014). And multiple sclerosis affects three times more women than men, although men with the condition develop neurological disability more quickly (see, for example, R. R. Voskuhl and S. M. Gold Nature Rev. Neurol.8, 255–263; 2012). Sex is a modifier of disease risk and progression.

Finally, King presents a long list of references showing sex-based brain differences; these papers appeared in the January, 2017 special issue of Journal of Neuroscience Research called “An issue whose time has come: Sex/gender influences on nervous system function.”  Click on the screenshot below to see it; I’m not sure if the content is available for free:

And the contents, miniaturized:

This is only a small sample of the relevant literature.


  1. ThyroidPlanet
    Posted April 11, 2019 at 10:24 am | Permalink


  2. Posted April 11, 2019 at 10:40 am | Permalink

    … the insupportable claim that every difference between male and female brains and behavior can be ascribed to plasticity, social conditioning, and our “gendered world.”

    A good question to ask a proponent of this position is, how did social gender (sic) differences arise in the first place? What, did they one day just rochambault to see who hunts and who gathers?

    • rickflick
      Posted April 11, 2019 at 1:41 pm | Permalink

      Rochambault meaning the game of rock/paper/scissors. What a great way to choose given no free will. See what you can learn on WEIT!

      • infiniteimprobabilit
        Posted April 11, 2019 at 7:32 pm | Permalink

        I’d suggest that since hunting may require greater physical strength, the choice wouldn’t need to be arbitrary. (I think that was Matt’s point.)

        Though rock/paper/scissors reminds me of an episode of the sci-fi Farscape where Crichton (the ‘hero’) was cloned by a bit of alien technology into an absolutely identical copy of himself down to the molecular level. The two Crichtons didn’t like each other very much and the episode faded on a scene of them doggedly and grimly playing rock/paper/scissors and tieing, every time.

        My immediate reaction was, that wouldn’t happen. But on reflection, in a determinate universe, if their brain states were identical at the start, it must happen.


        • Posted April 12, 2019 at 2:03 am | Permalink

          Yes, my point was that our culture arose out of, and bears the impression of, evolved behaviors.

  3. Randall Schenck
    Posted April 11, 2019 at 10:48 am | Permalink

    One hopes the science wins out on this as it should. Attempting to make something what it isn’t is a real disservice.

  4. Historian
    Posted April 11, 2019 at 10:49 am | Permalink

    Quillette has posted recently a strong defense of evolutionary psychology and the reality of differences in male and female brains. It is written by Alex Mackiel, who is an undergraduate. To the layman’s eye, it appears quite well argued, but since I have no background in this field, perhaps I am missing something.

  5. Linda Calhoun
    Posted April 11, 2019 at 10:53 am | Permalink

    Gender differences have already been used, many times, to justify racism and sexism.

    For me, the question is not whether differences exist, but exactly how do we accept those differences and not use them to attempt to limit peoples choices and opportunities.

    It was almost (but not quite) comical to hear Lyndon Johnson say that women are “slaves to their hormones”, while touting the reasonableness of men. Yeah, the same guy who never noticed his fellow lawmakers acting like a bunch of rutting stags was pointing fingers.

    Denial never works, for either side.


    • Ken Kukec
      Posted April 11, 2019 at 11:48 am | Permalink

      Poor Lady Bird.

      Her pic oughta be next to the dictionary entry for “long-suffering.”

      Though so should a lotta other FLOTUSes’, I suppose.

    • Joan L
      Posted April 11, 2019 at 7:21 pm | Permalink

      “how do we accept those differences”

      I just explain that I find sameness boring.

  6. Posted April 11, 2019 at 10:56 am | Permalink

    I’ve always thought there’s an implicit contradiction in ideological claims that there are no inherent neurological mean gender differences in biology and behavior. Wouldn’t that imply that sexual identity and orientation really ARE entirely matters of personal choice and/or cultural influence, and give support to the ludicrous Xtian notions that homosexuality is “contagious” and can be “cured” for instance? I mean, sure, the differences are multivariate and astonishingly complex, with a great degree of individual variation, but doesn’t the left just shoot itself in the foot (or the head) here?

    • Curt Nelson
      Posted April 11, 2019 at 2:21 pm | Permalink

      I’ve alway thought that sexual preference is a good example of a difference between the sexes, and as you said, denying it would mean that one does have a choice.

      Maybe they should also deny mental differences between species, because the existence of differences there that came about because of the different needs of each species, is also threatening to their position.

      Something I always remind myself of is that something like sex in humans shouldn’t be thought of as having been under evolutionary pressure since Homo sapiens arose, but since sex arose. Sex differences have been hammered into us a long long time.

  7. Ken Kukec
    Posted April 11, 2019 at 10:58 am | Permalink

    … a fear that if … sexes and different ethnic groups differ genetically—perhaps in part because of evolution—then that would somehow justify misogyny and racism.

    A fear not exactly unfounded. Look at what the “human biodiversity” crowd and the soi-disant “racial realists” and the white-supremacists at places like The Occidental Quarterly or V-Dare do with the slightest datum suggesting a racial of ethnic difference.

    That’s no excuse, of course, for ignoring those data or fabricating bogus explanations. The data are what the data are. Deal with it.

    • Posted April 11, 2019 at 12:30 pm | Permalink

      This “we don’t want to have to deal with the fall out” is Philip Kitcher’s reason why community vetoes on certain basic research are warranted. (I disagree, but that’s the argument.)

  8. DrBrydon
    Posted April 11, 2019 at 11:02 am | Permalink

    Almost all utopian projects rely implicitly on the idea that people can be taught to behave in a way contrary to their historical behavior. One of the requirements for that is also, unfortunately, that people who represent too strongly the chosen historical errors, or who can’t adapt, must be gotten rid of, usually not by buying them a bus ticket somewhere else (although the Nazis tried something like that as a cover story).

  9. Posted April 11, 2019 at 11:05 am | Permalink

    The book titles are so amusingly hyperbolic. Myths are Shattered. Myths are being Exploded. Paradigm shifts really happen pretty quietly, but of course agendas that claim paradigm shifts requires stronger verbiage.

    And the ideologues that wish to reply to these rebuttals will quickly point out that men are the ones doing the rebutting. That will be the. most. important. thing. to bring up.

  10. Liz
    Posted April 11, 2019 at 11:19 am | Permalink

    This looks interesting: “An issue whose time has come: Sex/gender influences on nervous system function.”

    I would love to read 65, 176, 189, 213, 279, 311, 355, 371, 518, 527 (definitely would love to find this), and 617.

    I was unable to access these.

  11. Posted April 11, 2019 at 11:25 am | Permalink

    It’s frustrating — the answer is clearly both/and, not either/or, but so many people have trouble grasping that. Human brains differ (on average) by sex. Human behavior is strongly, hugely, influenced by experiences including the society we grow up in. Neither of those facts determines what rights humans of either sex have.

    • Posted April 11, 2019 at 12:08 pm | Permalink

      It’s frustrating

      I couldn’t a free more. The whole “nature versus nurture” debate has always seemed to me to be bogus. Sometimes it’s one, sometimes it’s the other, sometimes it is a bit of both. Often we don’t know the mix.

    • Posted April 11, 2019 at 12:54 pm | Permalink

      Yes. And then there is the ongoing confusion over terminology like sex versus gender. That confusion at least is pretty understandable.

    • A C Harper
      Posted April 12, 2019 at 5:48 am | Permalink

      Plus there’s also the ignored extremes. You can reasonably argue that the average male brain and the average female brain contain many similarities and some differences – which all amount to a maybe yes, maybe no, on the significance of any particular difference.

      But, edging out further along the data vs social preference plank, what about comparing the malest male brains against the femalest female brains? Assuming such things can be identified of course. Jordan Peterson (love him or loath him) points out that male and female traits are often mapped by closely overlapping distributions – which supports the argument that differences are not ‘significant’. On the other hand, he says, the extremes of those distributions are often far apart… and this is what we notice in daily life *because it is so obvious*. What we do about that is a separate matter.

  12. 355101pkl
    Posted April 11, 2019 at 11:29 am | Permalink

    A few years ago, there was an article in the BBC news about a parent that withdrew his child from school due to gender assignment. Apparently one of the boys in the 8 year old’s class was turning up to school wearing a dress and the parent who withdrew the child took exception to the school saying it was OK if the boy wanted to be a girl, The objecting parent said that his own son in the same class, was becoming very confused by the boy dressing as a girl It seems the father was Christian and his objections may have had religious undertones. I am not a Christian but I happened to be in agreement that children should not be bombarded by gender neutrality issues at an early age and that children should be taught to take pride with the sex that they are born with particularly if they are at an age when they can be easily influenced . The article turned up on my facebook page and I commented that i thought it fortunate my own children were lucky not to have been through that kind of thing whilst they were at school. I found the next day i had been unfriended by a woman whom I knew as having a an array of wildly left wing views . I am a pretty sure my comments were the reason. I noticed that attached to the article was a long series of comments all of whom condemned the Christian parent for withdrawing his child and calling him a sexist . It was like an hysterical witch hunt. I was quite amazed that not one commentator had stood up to defend the parent who took their child from school. Be warned a mob is out there ready to descend on and silence anyone who opens their mouth to explain to boys and girls that their gender has a history of facts .

    • Posted April 11, 2019 at 12:14 pm | Permalink

      I would say the Christian parent was wrong to withdraw their child from school. He was damaging his child’s education for his own principles.

      If the child really was confused, it was probably only because nobody had taken the time to explain the situation to him in an honest way.

      • Mark R.
        Posted April 11, 2019 at 1:06 pm | Permalink

        I agree with you (and Ken below).

      • Posted April 11, 2019 at 2:19 pm | Permalink

        If the child really was confused, it was probably only because nobody had taken the time to explain the situation to him in an honest way.

        I agree – but there’s zero chance that a school would explain what’s going on in an honest way in the current cultural climate.

      • Posted April 11, 2019 at 3:32 pm | Permalink

        And the situation is…? A child of that age can say he wishes to be e.g. an eagle. Someone is supposed to be the adult in the room.

        The school is crazy. But I agree that the parent was wrong. He had to tell his child that education is important and some things must be ignored. Moving the child to another school has its own sequence of problems and is not guaranteed to solve the original one, because ALL schools have been instructed to reinforce gender confusion.

    • Ken Kukec
      Posted April 11, 2019 at 12:15 pm | Permalink

      “The objecting parent said that his own son in the same class, was becoming very confused by the boy dressing as a girl[.]”

      Really? How hard could it be?:

      “Son, that boy feels more like a girl, so he dresses like one. That’s his business, and his family’s, and nobody else’s. If anybody picks on him, tell ’em to take a flying fuck at a rolling doughnut.”

      OK, I might paraphrase that last line slightly for an eight-year-old. But that’s about the size of what I would’ve told my sons had the situation ever arisen. And it damn well oughta be sufficient to put the tyke back on his bearings.

      • Posted April 11, 2019 at 12:29 pm | Permalink

        Perhaps “flying fuck at a rolling crumpet”?

      • Posted April 11, 2019 at 12:55 pm | Permalink

        Flying fuck at a rolling doughnut? Have not heard that since the late fifties. Damn, you must be old.

        • Ken Kukec
          Posted April 11, 2019 at 1:09 pm | Permalink

          I’m old, but not as old as “Old Guy,” Mr. Silent Generation. 🙂

          I recall Vonnegut using “flying fuck at a rolling doughnut” in Slaughterhouse-Five.

          I also remember hearing it from some other guys from my old man’s generation, once I got to an age (around late adolescence) where they were comfortable cursing in front of me.

          • Posted April 11, 2019 at 1:16 pm | Permalink

            We discovered it in eighth or ninth grade. Mainstay of our high school conversation. Good old days.

            • infiniteimprobabilit
              Posted April 11, 2019 at 7:37 pm | Permalink

              Must be a USAnian expression. First time I’ve ever heard it (the doughnut bit at least), and I thought I’d heard most of ’em…


    • Rita Prangle
      Posted April 11, 2019 at 12:58 pm | Permalink

      I gather you have no actual experience with transgender children.

    • Posted April 11, 2019 at 1:44 pm | Permalink

      It does seem to be a lot for young children to handle. It would indeed be confusing at first. But a patient and honest explanation can start the process of understanding and it is a fact that children do learn to just take it in stride. Children are confused literally all the time, but they are amazingly flexible and we should give them credit for that.
      But this Christian parent is likely to be the wrong one to teach them about tolerance.

      • Posted April 11, 2019 at 2:28 pm | Permalink

        Children are confused literally all the time

        Yes, they are. But why is it only the boy who’s parents believe in sky fairies who is confused and not the boy who’s parents think he’s a girl?

        • Posted April 11, 2019 at 3:04 pm | Permalink

          I have not looked into this one, but it is most likely it is a case where the boy has the gender identity of a girl. I doubt the parents are confused. They are most likely trying to accept this reality and are doing the best they can.

          • Posted April 11, 2019 at 3:40 pm | Permalink

            Today, the first hint of a gender confusion is perceived as a reality and all are required to reinforce it. I think that the majority of these cases would resolve spontaneously without the artificial support.

            • Posted April 11, 2019 at 6:12 pm | Permalink

              I can only speak of it anecdotally in a handful of cases. I know of two parents whose child really was transgendered, and the parents were pretty upset; they resisted for a time, but to their credit they rallied and did their best to support their kid. I know of kids who did play at cross-dressing but nothing came of it and none of those parents tried to prematurely ‘flip’ their child. Going in that direction is one of the most isolating things there is, and I know of no parent who would want that for their kid.

  13. Jon Gallant
    Posted April 11, 2019 at 12:20 pm | Permalink

    Left ideologues use seemingly virtuous goals to justify unspeakable means—as in their invariable fantasies about revolutionary violence—and also to justify the choice of things treated as facts. Hence their refusal to process any data about the tyrannies that emerge from actual revolutions, and their hostility not only to Evolutionary Psychology but to Biology in general. It is a frame of mind obsessed with abstract goals while being oblivious to data.

    Wouldn’t it be valuable to have studies of the Neurobiology of this anti-empirical mindset? What about fMRIs on activists of this sort, compared with appropriately chosen control subjects? We might also inquire into how much of the mindset is hard-wired, and how much is learned from exposure to, say, the HuffPost, particularly at an early age.

    • Steve Gerrard
      Posted April 11, 2019 at 6:02 pm | Permalink

      I re-read this with the first word changed from Left to Right, and it sounded just as good and made the same point.

      A really interesting question would be is there a brain difference between Lefties and Righties? Maybe that’s why were stuck in an infinite loop.

      • A C Harper
        Posted April 12, 2019 at 5:58 am | Permalink

        I’ve read that people holding Leftish or Rightish political views map differently onto the Big Five Personality Traits. But research is ongoing.

        Does the embodied brain cause the personality traits? Is political preference dominated by your personality traits? I don’t know, but it will take a lot of work to untangle all the confounding factors.

  14. Joe Dickinson
    Posted April 11, 2019 at 12:23 pm | Permalink

    I’v always thought it was a mistake to base a policy of equal treatment on the claim that there are no biological differences. A policy of equal treatment no matter what the biological reality might be does not risk being overturned by new data.

    • Curt Nelson
      Posted April 11, 2019 at 2:24 pm | Permalink

      Yes. All men are not created equal, but they are all created with equal rights.

  15. peepuk
    Posted April 11, 2019 at 12:33 pm | Permalink

    “since equality is a moral stand that is independent of biology”

    Sure, but with biology we can do even better and defend that from an objective point of view no creature has more value than any other living thing.

    Humans are basically a container for water (60% of the human adult body).

    And human cells make up only 43% of the body’s total cell count, (see “”).

    This proves life is one big (sometimes happy) family build from the cheapest materials.

  16. Posted April 11, 2019 at 1:01 pm | Permalink

    Disturbing that the blank state theory lives on.

    Right wing does not accept science on climate change and evolution.
    Left wing does not accept science on sex or ethnic group brain differences.

    Progress is slow going sometimes.

    • Curt Nelson
      Posted April 11, 2019 at 2:42 pm | Permalink

      And they both don’t accept it for political reasons. Lame.

    • Posted April 11, 2019 at 3:46 pm | Permalink

      They believe in blank state only when it suits them. Try to tell them that, because child’s brains are blank, transgender and gay individuals could be conditioned to be heterosexual and matching their biological sex.

      • Posted April 11, 2019 at 4:09 pm | Permalink

        Good point.

  17. Posted April 11, 2019 at 1:21 pm | Permalink

    Making the blank slate argument is equivalent to making a geocentric Earth argument.

  18. Posted April 11, 2019 at 4:27 pm | Permalink

    These adherents to outmoded, outdated dogma are in a stunted, stumped stupor, blinded to their cause by a short cut to equality based on misinformation, false claims, straight out lies. This is faulty and damning progress to real understanding.

  19. Posted April 11, 2019 at 6:05 pm | Permalink

    So far as I understand it, ever since the European Enlightenment, political equality and democracy have been philosophically justified by the epistemological egalitarianism of the blank slate notion. Obviously, it should now be evident that we are not born blank slates. What we need, then, is a justification for political equality and democracy that is not grounded in that notion. And I think there might be a few such justifications. Hence, the issue to me is whether the new justifications will catch on. That’s a much more political question than either a scientific or philosophical one.

  20. KD
    Posted April 12, 2019 at 7:35 am | Permalink

    I get the ought/is gap arguments, but the Progressive take as I understand it is:

    i.) there are no innate differences between different groups of people.

    ii.) differences between people are caused by the more successful group oppressing the less successful group, essentially stealing their potential in some conscious or unconscious way.

    iii.) differences between people must be eliminated through government intervention in society until equality of outcome is achieved.

    iv.) Social justice is essentially restitution to the victims of oppression, and therefore truly accords with justice. We must fight to achieve diversity and inclusion.

    Obviously, if premise i.) and premise ii.) are not scientifically palatable, or even if ii.) is only partially or marginally true, and most difference can be accounted for by genetics and/or cultural/environmental differences between groups, then pushing equality of outcomes through government bureaucracy is not justified on grounds of restitution.

    For it to be just, there must be an active (if unconscious) conspiracy by group X to keep down group Y. It can’t be that group Y just prefers being a pediatrician to being an engineer, and group X the reverse.

    Further, if “social justice” is cannot be justified ethically on grounds of restitution, it actually moves over into extortion and blackmail. After all, if you extract money or other benefit from someone on false pretenses or threats, you are committing either fraud, extortion or blackmail.

    It starts to look more like political extortion, the losers ganging up on the winners to steal their lunch money. Hence, why we can’t have these kinds of discussions anymore, any more than Jimmy Hoffa is going to permit a transparent investigation into the influence of organized crime on the Teamsters.

  21. KD
    Posted April 12, 2019 at 7:51 am | Permalink

    Part of the problem with the Enlightenment and post-Enlightenment politics is that the Enlightenment was invested in clearing away the last vestiges of feudalism from society, and the insistence on equality was about trying to abolish different legal classifications (and rights and privileges) between different groups.

    Of course, feudalism was probably a successful social system for as long as it was because (unlike Marxist-Leninism) it accorded with human nature. If there was a large-scale collapse in social complexity, would anyone be surprised if things reverted back to a feudal order? The point is that the Enlightenment was driven by political objectives, and deliberately suppressed and underplayed aspects of human nature, so whatever its benefits politically, its not a good place to start for a philosophical anthropology.

    Of course, “equality” today is being used to justify different legal classifications (and rights and privileges) between different groups, whereby groups with the most intersectional pokemon points get the most rights and privileges, and the “oppressors” are second class citizens, subjected to legal discrimination and general vilification. In some respect, it is a return to feudalism and caste.

    However, modern “equality” is distinguishable from feudalism and caste because unlike feudalism and caste, it insists the worst is the worst because of the best, and seeks to create an inverted social hierarchy. It combines the worst aspects of the Enlightenment with the worst aspects of feudalism.

  22. Posted April 12, 2019 at 12:23 pm | Permalink

    Reblogged this on Peddling and Scaling God and Darwin and commented:
    An interesting blog on whether there a sex differences in human brains

    It does seem that there are and no amount of pleading can deny it!!

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