Human Brains Are Neither ‘Male’ Nor ‘Female’

By Nathaniel Scharping | December 1, 2015 5:23 pm
male-female-cover

(Credit: Leszek Glasner/Shutterstock)

The physical differences between men and women are pretty simple to decipher from an anatomy book, but those categorical dividing lines disappear when it comes to the brain.

Going back nearly a century, scientists have attempted to determine whether the brain structures of men and women, like our reproductive organs, fell into separate and distinct categories based on sex. Gender-based differences in the brain, the thinking goes, could explain variations in behavior between men and women. But searching for distinctly male or female brain identifiers may be a fool’s errand: Researchers at Tel Aviv University, in a new study, demonstrated that our brains are actually an unpredictable mash-up of male and female characteristics.

The Same in the Brain

If our brains were truly sexually dimorphic, there would be consistent differences between the male and female brain, and scientists have conducted numerous studies designed to find them. A 2014 meta-analysis of more than 100 studies on sex differences in brain structures found, for example, that men’s brains are 8 to 13 percent larger than female brains, on average. Parts of the brains that control language, memory, emotion and behavior also varied in size between men an women, according to the meta-analysis. In a 2013 study, scientists concluded that men possessed bigger brains optimized for math and reasoning, while women’s brains were better connected and more suited to empathy and collaboration.  These characteristics were believed to stem from basic differences in brain design — your brain’s either male or female.

But after conducting a study of 1,400 men and women using four different datasets, researchers in the current study concluded that instead of having either one kind of brain or another, most people’s brains fall somewhere in the middle in terms of possessing male and female characteristics. According to the team, our brains are “mosaics” of features, some of which are more common in men, and others more common in women. For example, men typically have a larger amygdala, while women have greater cortical thickness. In their analysis, the team focused on the 10 areas of the brain that varied most between sexes, and categorized the variations as either male or female.

male-female-brain

The volumes (green = large, yellow = small) of brain regions in 42 adults. The coloration highlights the substantial overlap between male and female brains. (Credit: Image courtesy of Zohar Berman and Daphna Joel)

Researchers used magnetic resonance imaging (MRI) to search for differences in volume and the level of connectivity between regions of grey matter in the brains of 112 men and 169 women between the ages 18 to 79. When researchers looked at the 10 most dimorphic regions of the brain they had identified, they found that there was substantial variation between subjects no matter their gender, and that only 6 percent of the brains they analyzed were either “all-male” or “all-female.” In other words, they found little gender-based consistency in our brains, and that lack of internal consistency undermines previous conclusions drawn about a male-female spectrum of brains. Researchers published their findings Monday in the journal Proceedings of the National Academy of Sciences.

The team corroborated their findings using data from a behavioral analysis study of 5,000 university students that attempted to categorize participants based on gender-specific activities such as scrapbooking and playing video games. Just like the brain study, the behavioral study found that male and female subjects engaged in a range of activities not necessarily defined by gender.

Spotting Differences

Researchers argue in their paper that we should avoid classifying brains as whole, and we should instead look at specific regions of the brain when differentiating between males and females. For example, a woman could possess a large deep limbic system typically associated with females, but also have a large inferior-parietal lobe, which guides numerical brain function and tends to be more dominant in men. Rather than being a byproduct of design, researchers suggest that masculinization and feminization of the brain are two different processes that occur independently in different regions of the brain. Further, this process is affected not only by gender, but by environmental and genetic factors as well.

“Specifically, we should shift from thinking of brains as falling into two classes, one typical of males and the other typical of females, to appreciating the variability of the human brain mosaic,” researchers wrote.

 

 

CATEGORIZED UNDER: Mind & Brain, top posts
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  • OWilson

    So, those aggressive, deadbeat dads have been taking a bum rap all these years ?

  • moderatelymoderate

    This suggests culture has a bigger role then in aggression, emotionalism, etc.

    • splashy79

      I’m thinking that culture really does have a bigger role.

  • incroal

    just another specimen of transgender propaganda folks, move along.

    • disqus_2nDHANf4oU

      Right! Tell us about the studies you’ve led. I’m sure your data is better than theirs.

      • OWilson

        To “normalize” the transgender it is essential that we believe there is no significant biological gender difference.

        Thus the tranny is “normal”.

        We have “normalized” gays, and that wasn’t a big deal.

        But now we have stepfathers wanting to “marry” stepsons, so all bets are off for the future of consenting relationships.
        Old Grandpa and his granddaughter, old uncle Joe and his three sisters.

        Let’s just celebrate the love, y’all!

        • Mike Richardson

          Big surprise we’re getting the Rick Santorum view of human sexuality from you, Wilson. Are you also going to offer Ted Cruze’s view on the motivation of the Colorado Planned Parenthood gunman, as well? Apparently celebrating the hate, y’all.

          • OWilson

            Don’t be judgemental.

            If it feels good, hey!

            Let the love flow man, far out!

      • incroal

        I didn’t lead any studies, but only a moron is incapable of intuiting that male and female brains are fundamentally different. Basic anatomy shows Male brains are 10 percent larger that female. I’m guessing your female…

        • L. Haze

          You do realize that bigger brain =/= more intelligent? That belief got thrown out in the 20th century. Are you from the 50s or something?

        • L. Haze

          “I’m guessing your female….”

          Did you mean “you’re”? Amazing how you’ve got the advantage of having a “male brain” and yet you still manage to this dumb.

          • incroal

            Size of the cortex actually. More folds and surface area means more processing power.

          • L. Haze

            Lmao then why aren’t humpback whales, who have incredibly convoluted brains, more intelligent than we are?

    • AngelaT

      Actually, this might go against them, at least the way they claim it. One of the common theories of transgenderism is that the source of differentiation between sex and gender in those who are transgendered is certain neurological processes or brain structures typical of the other sex. It’s not that they have, say a male body but a female “soul” or mind, but that they have a male body and a female brain, or vice versa. Saying “no female or male brains” wouldn’t really help their cause, because it could more easily render their claims to be a different gender merely psychological claims.

      Mind you, I don’t think the study proves as much as they claim. They throw the stat around of only 7 or 8% having all male and all female brains, but they conveniently leave out the percentage of women who have “largely female” brains or “largely male brains” as a whole. It’s not enough for me to state that I have little empathy, and am more geared towards STEM. those are only a few things where I deviate from the statistical norm. But there are plenty other areas where I fall right with the norm.

    • L. Haze

      Lmao are you joking? Transgenderism is all about men and women being innately different.

    • L. Haze

      Scientific data = propaganda? Next you’ll be telling me climate change isn’t real.

  • César Alejandro Lara

    This does not change the perspective that men and women are different and not everything is a social construct.

    • splashy79

      People are different from each other, it’s not really ordered by gender.

      • César Alejandro Lara

        Its not entirely. But sex has something to do defining who you are.

    • L. Haze

      It’s about nature vs nurture. Apparently that went way over your head. Maybe my “male-like” brain helped me figure that one out despite being an intellectually inferior female in your eyes. Lol

  • César Alejandro Lara

    This study just shows that my brain is different from yours not matter
    my sex or yours. Men are still better at math and women are still better
    at empathy. I don’t have a male brain, I have a male-like brain. Its
    what I understand from this study.

    • saymwah

      How exactly do you know that you have a “male-like” brain, as opposed to just being too insecure in your masculinity to engage in stereotypically feminine activities?

      • César Alejandro Lara

        I guess I have a male-like brain because I’m a man and thats what I got from the study, men have male-like brain. Those whose brains were all male or all female were the opposite sex? I don’t think so, they would have wrote that down to feed their narrative.

        • L. Haze

          The study literally says there aren’t significant differences between male and female brains and here you are saying “men have male-like brain”. If logic and reasoning are “male traits” then I hate to break it to you but you are sorely lacking.

    • splashy79

      Actually, in other cultures women are considered to be better at math, and appear to be. It’s more cultural than gender driven.

  • saymwah

    Ding! Calling all deep-dyed sexists to insist that “men and women are different” despite all evidence to the contrary.

  • Paulo Pinheiro

    “According to the team, our brains are “mosaics” of features, some of which are more common in men, and others more common in women”. This is what I always thought of male and female brains! What were they expecting?
    It’s like ‘according to the team, there is no specific height for males and females, some women are taller than some man and vice-versa’

    • Ian Patrick Francis McKay

      One difference is that men, on average, are taller than women. Yes, there are exceptions, but men tend to be taller than women. There is a consistency there. This research demonstrated that there is no consistency in brain differences. A woman is just as likely to have an “all male brain” as a man is. However, with height, a woman is not as likely to be 6′ 5″ as a man is. Men are more likely to be taller.

      Regardless, there is anecdotal behavior (things we observe on the day to day– patterns we construct from our own perspectives) and then there is scientific research which attempts to remove our biases from the picture. And often times that research corroborates what we are already seeing, but sometimes it doesn’t. It doesn’t matter what they expected, only what results they actually got.

  • splashy79

    There are more differences between men and men, and women and women, than there are between men and women. The veneer of culture makes it appear as though men and women think differently, but the reality is we are all different, and it all overlaps a lot.

  • P.Mathivanan

    Gender gap will assume less importance once robots start doing all our works free of cost.

  • arch 1

    I hold that some functions attributed to brain are spread through other organs of the body. Things like emotion/love/hate, or the intuitive , gut feeling . It is proven there are neuron clusters other than in brain.
    There is no cognitive difference between the sexes but there are most certainly other differences.

  • Ryan

    THERE IS NO SUCH THING AS FEMALE OR MALE BRAIN , the variation differences in diferent areas in our brains are modeled by genetic and envviromental factors. a woman who is a teacher of mathematics will probably have a greater volume of the area responsible for reaspning. A man who is a taxi driver will probably have a greater volume of the area resppnsible for decision making. there is a very good book about it ,calle the brain that transformers itself or something like this. (Dont know the name in english) gender has nothing to do with brain size , genetics and our envirroment are responsible for it.

  • Kevin Davidson

    What is women’s ‘intuition then? I suppose its peoples intuition now.
    I always thought that women have an abstract thought process when navigating a problem, and men take a more linear approach. The female can solve problems or recognize likely outcomes by tapping into their intuitive senses. This is a result or nature or nurture? Men just have to be encouraged to tap into their intuition.

    • rachel francon

      The brains have deep and abiding “functional differences” on our observational level…and these functional differences result from deeper cell based layers of structural differences such as characterize the cell membranes and the methylation of the genes in different cells. The astroctyes are a prime example of a deeper structural difference that results in such “pop concepts” that are valid…as “women’s intuition”.

  • rachel francon

    This publication is sheer and utter nonsense in the way it’s characterized. They are obtuse enough to ask a “stupid question” and then proud of themselves for coming up with a ridiculous and evasive answer to the stupid question they shouldn’t have asked. Utter intellectual and medical RUBBISH

    This is not really a science problem but more or less an “idiot’s delight” on the part of scientists who couldn’t pass a high school logic course But the way the world is no one believes that you have to be “able to think” first yourself before you can comment and be published by the medical paparazzi…and shame on the further and greater fools in Discover magazine to buy into this sophomoric stumbling.

    What they actually find is that there are significant differences in the brains of males and females. But since all males are not identical and all females are not identical to some ideal Platonic form, there is a more complex and interesting way to speak about these “differences” beyond the stupid question and even more outrageous misleading answer that they present an audience.

    The problem with most medical researchers is that they are functionaly ILLITERATE both in terms of science in other areas of research (Schodinger called them the ‘barbarians of our age”) and in terms of simple logic or mathematical logic.

    There are no grays and there is no spectrum at all…because the two endpoints which these intellectual sad sacks seek to connect with all the “grays” don’t exist at all in the first place…and can’t exist…because they are idealized abstractions.

    Just like black and white, or zero and infinity are idealized notions that help us deal with problems occasionally, they are multidimensional. The world is not stretched out on a one dimensional idiot’s tightrope between “black and white” but is a rainbow of colors variant in multiple dimensional..not just grays.

    Similarly the same stupidity afflicts such conversations as that in politics dealing with “Left” and “Right”. These are also idiot’s delights. and ridiculous as endpoints of a spectrum between them and known to be so when we find that everyone has some left and some right opinions and there is no simple straight line between the two.

    If one studies mathematics and numbers, one finds the same thing. It serves no purpose to say that we can understand al the numbers including integers, rationals, reals, imaginaries and complex and so on by stringing a rope between two ideal endpoints zero and infiniti and seeking to understand how to count and calculate smile emoticon These people are utter fools..and the people at Discover are even more foolish to simply blindly write this up in this silly and misleading form.

    The messy business of understanding the term “all” as in “all the properties that go into a classification” has been a major concern of the greatest minds of the twentieth century and the inadequacy of this kind of ignorant usage of the term has been pointed out first by Bertrand Russell in his dealing with “theory of types”, then by others such as Quine (one of the most respected of philosophers of language and logic) and then by Kurt Godel, whose work ultimately dealt with aspects of this everyday problem but revolutioned our understanding of all mathematics and classification in terms of “sets”.

    It is a disease of our times….as we can see by how similar fools pollute the media in discourse in many other areas where the dumb question of “finding the right shade of grey” is posed…..as if that’s a smart thing to do….and that only creates of temple of worship for “black” and “white” while excluding more sophisticated and satisfying discourse in terms of reds, blues, greens and the even the gorgeous arrays of purple available to us :)

  • Doctor Mayhem

    So… this also ignores 37 Trillion chromosomes? Men and women don’t think alike and we are not interchangeable. Discover has degenerated into nothing more than being yet another leftoid hack spankrag so that calls itself “science.”

    Meanwhile, new studies show that patriots (right-wingers) and traitors (left-wingers) have differing brains, with different sections of it with different development. So if political partisans can be shown to have differing brain structures and brain patterns, then how can men and women not have the same?

    More smug leftoids who pose as scientists and fall in love with the smell of their own farts.

    Kill yourselves.

  • Fahrenheit 616

    One study does not reverse all other studies on the same subject that have come to completely different conclusions. Just because it’s the current year doesn’t mean your political ideology negates scientific ethics.

  • Johanna Vienneau

    This has nothing to do with the content of the article, but someone made a mistake with the symbols. On pages 52 and 56 the symbol for female is in blue and is describing males, and the symbol for male is in pink and is describing female. Oops

  • JAFischer

    Once again, reality fails to conform to social expectation.

  • http://www.E-alloftheabove.com Oldbear

    There are about 25,000 genes present in each of us, with 2 copies of most genes, but only a very few determine sex. Basically only one (testicle determining factor) makes you a male, all the remainder are similar in both males and females. The responses of the other genes to sex hormones and sex determining factors (such as prenatal influences) may be male-like or female-like. So, perhaps we are all potentially female, but some chose to develop and act like males, while some males chose to act like females. All organisms have variability within their populations and I would expect to find a wide spectrum of behaviors and structural “enhancements” among the population (s). Selection pressure will eventually affect what you see if you watch long enough. Give it a few thousand years and see!

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