December 1, 2015

New Brain Study Indicates Great Gender Diversity

I would like to draw your attention to a recent article in the Guardian, which covers the research of a Israeli research team who have found that there is a huge overlap between male and female brains.

A complex mix of the "feminine" and the "masculine"
The volumes (green = large, yellow = small) of brain regions in 42 adults, showing
the overlap between the forms that brains of females and brains of males can take.
Image by Zohar Berman and Daphna Joel

The main point for me is not whether these researcher are "right" or not. Neuroscience is in constant flux, and there will probably never be a final theory that explains everything about this extremely complex organ.

What is interesting for me is how similar research data can lead to very different conclusions all depending on the point of view of the researchers.

The Guardian writes:

'Scientists analysed brain scans of more than 1400 men and women and found that while some features are more common in one sex than the other, each person’s brain has a unique “mosaic” of these features, as well as others seen commonly in both.

“What we show is that there are multiple ways to be male and female, there is not one way, and most of these ways are completely overlapping,” said Daphna Joel, a psychology professor who led the study at Tel-Aviv University.'

Scientists inclined towards gender stereotypes will focus on the macro level

This is nothing new. Even the neuroscientists who believes strongly in the dichotomy between "male" and "female" brains know that there is a lot of variation between individual brains, both male and female, but they interpret patterns they see on an aggregated level as proof of there being unique "male" and "female" brains. 

These aggregated findings are then used to confirm the gender stereotypes of the -- let's say -- sexually driven aggressive man and the passive and nurturing woman.

Overlap is the norm, stereotypical brains the exception

What is interesting with this study is that the researchers focused on the areas where there is least overlap between men and women on an aggregated level.

The Guardian again:

'Across the four different sources of brain scans they studied, the scientists found the percentage of “internally consistent brains”, in which all regions were at the male end or all at the female end, varied from zero to 8%, while those with both male-end and female-end features ranged from 23% to 53%.'

So even if you look at those regions who are supposed to prove that men and women are different, you find that most men have "female" traits and most women have "male" traits. At this point, of course, you have to ask yourself whether it makes any sense at all to call these traits "male" and "female."

The Slider Model

This is actually where I can say "I told you so!" 

I presented a similar "mix" model of gender traits, abilities, sexualities and interests back in 2010, in the blog post "The cause of crossdreaming - an alternative model". I did so, not because I was way ahead of contemporary neuroscientists, but because this is a way of thinking that goes all the way back to the 19th century. 

This "new" way of looking at the brain biology of sex and gender is very similar to the one of -- for example -- Magnus Hirschfeld, the great pioneer of transgender research, as presented in his book on transgender people in 1910.

This research does not solve the nature/nurture riddle

Does all of this mean that there cannot be a biological component to transgender conditions, and that the social constructivists were right all along? This is all about nurture and not about nature?

No, this research cannot be used to prove either of these standpoints. Brains are flexible; they change with the way we use them. Whatever it is these scans measure, it can be inborn, the result of a brain adapting to social training and external stimuli or (most likely) a combination of  both.

There may still be parts of the brain that triggers people to orient themselves in the world as men, women or something else entirely. We simply do not know.

What the research does indicate, however, is that there are no fixed gender traits unique to each gender, and that having interests, abilities or desires normally allotted to "the opposite sex" is the norm, not the exception.

Daphna Joel explains why the idea of male and female brains are much more complex than many believe in this popular TEDx talk. Note that she actually dismisses the terminology of "male" versus "female"parts of the brain, even if she uses the terms to make her point. "It is meaningless to talk of the sex of the brain," she says.

Daphna Joel, Zohar Bermanb, Ido Tavorc, Nadav Wexlerd, Olga Gabera, Yaniv Steind, Nisan Shefia, Jared Poole, Sebastian Urchse, Daniel S. Marguliese, Franziskus Lieme, Jürgen Hänggif, Lutz Jänckef, and Yaniv Assaf: "Sex beyond the genitalia: The human brain mosaic." Proceedings of the National Academy of Sciences 2015.

Magnus Hirschfeld: Transvestites: The Erotic Drive To Cross Dress 1910/1991, Translated by M. A. Lombardi-Nash


  1. I think this shows there is two components to the experience of gender. The sexed self which extends to the brain too in the form of brain body map, link up between the hormones and receptors in the brain etc and brain regions there to cope with how the sexed bodies function. All these factors likely contribute to sense of core gender identity as male or female or other.

    The other component is a persons sense of gender is orientation towards activities and behaviours culture has sorted into a binary labeled masculine and feminine. This may influence how people want to dress, speak, the things they like to do to a greater extent than gender identity. The BEM sex role inventory described masculine and feminine as instrumental and expressive, and claimed people had orientations towards gender trait behaviour based on which cluster of traits they had. I think that later on everything got grouped together with gender identity and ended up on the same spectrum.

  2. I think you are on to something here.

    Interesting parallells for me are instincts like hunger, language and play.

    Hunger is clearly a deeply embedded biological instinct. Without it you die. However, our personal preferences for food are at least significantly influenced by culture. Your enthusiasm for Chianti is clearly not biological.

    All human children has a pre-symbolic drive towards talking. But what language they learn depends on where they are brought up.

    All kids have a strong drive towards playing (as do most mammals, I believe), but what games they play are at least partly influenced by the cultural context.

  3. You should read this:

    The conclusions that the Joel paper argues for, and the statements they've made to the press, are highly misleading. In this day of clickbait journalism, that's what gets rewarded, but we should try to avoid promoting such poor research more than it already is.

  4. That is a good find! I will include in the literature list.

    I also believe there is much to be said about the interpretations of statistics, and how weakly founded this methodology actually is.

    Anne-Fausto Sterling, Cordelia Fine and Lise Eliot have made a similar argument, but in reverse, arguing that neuroscientists and sexologist have a tendency of exaggerating the differences that are there. (See references on this page)

    For me the main problem is that even if there are statistically significant differences, that does not help me understand transgender.

    Even Baron-Cohen, the main that most clearly has argued that there is such a thing as a "female brain", must admit that less than 50% of the women mapped by him have "female brains", as defined by him, and at that point the hole concept becomes pretty meaningless.

    Furthermore, given that we know that upbringing and socialisation not only give men and women different life trajectories, but also poses different expectations on them -- expectations that clearly influences the way they respond to questionnaires and research interviews -- much of the difference might actually be a cultural artefact, and not the result of differences in biology.

    Scanning or dissecting brains cannot give us definite answers, either, as brains are plastic and change with use. It has become extremely hard to see where nature ends and nurturing starts. (Maybe it is better to look at human beings as complex systems created by an interaction between social and biological factors.)

    Anyway. My problem is that since the female and male bell curves are nearly overlapping, we have to face the fact that someone who was assigned woman at birth, has two X chromosomes, identifies as a woman and who feels like a woman, may nevertheless present "masculine" scores on all relevant indicators. As the paper referred to in this blog post points out: There are few if any "perfect" males or "perfect" women out there.

    This tells me that gender identity cannot be the sum total of gender traits. That does not mean that there cannot be a biological basis for gender dysphoria. I believe there is at least a strong biological component to it. But this component cannot be explained as having a "female" or a "male" brain, in the Baron-Cohen sense of the word.

    I am more and more inclined that there are inborn drivers that are not defined by gender specific abilities, traits or interests, but rather by a drive towards orienting ourselves in the world as male, female or a mix of the two.

  5. Hello,

    I met Dr. Joel earlier this year when she gave a talk at a Stanford meeting about transgender. She presented her research and findings. After, we exchanged a couple of emails where I tried to point out, as respectfully as I could, that I felt her conclusions are flawed: just because she didn't find no statistically meaningful differences between the areas she studied, with the tools she has (which she admits have limited resolution), and a small sample size (which must be limited because of, here again, the tools she has) doesn't mean the differences she didn't find are not there. She was gracious and I encouraged her to keep looking.

    I certainly don't know where my gender dysphoria came from. I just know I have experienced it since I was 4 or 5. After a lot of study, therapy, and group meetings I know it's real. Took me a long time to get to this realization and acceptance as I'm almost 60!

    Happy holidays,


  6. I apologize for misspellings in my previous comment. I have to stop using the ipad for this kind of thing.

    Thank you for a very interesting comment, Emma. I think you are right, in the sense that the scientists are just scratching the surface here. We also have to keep in mind that neither brain scans or autopsies reveal everything that goes on in the brain. If there is a biological trigger for gender orientation, that does not have to be visible in the kind of data they are looking at. After all, so far the neuroscientists have tried to identify "male" and "female" brains on the basis of gender stereotypes. There may be something else and far more fundamental leading to various types of gender identity and orientation.

    Like you, I like to start with the gender dysphoria. It is real. It is persistent. It cannot be explained a way with a "but".

    What do you think they should be looking for?

  7. That is certainly a $64,000 question, and it's fun to think about. If I was a neuroscientist I would prefer to increase the number of needles in the haystack I'm searching for. For example, instead of just looking for male vs. femaile, I'd look for all characteristics I could find that are binary, such as gay/homosexual or not, and then try to build a database of the brain details I can isolate, and look for correlations. Quite possibly a life's work of frustration, wondering if I have only compiled a list of false negatives! But wow, probably a Nobel if I was able to conclusively isolate a difference that leads to an "instinctual" difference in thinking.

    But I agree with you that she may be barking up the wrong tree entirely. Maybe it's nature vs. nurture. Or, perhaps its chemical rather than physical. I'm an EE by training but work in marketing high tech. As I think about it now, this kind of science and investigate sounds like it would have been very interesting. I've made career changes in the past but this sounds way too far off the mark for me at this stage in my life!


  8. I think you right. As long as they are only studying the "female brain" vs. "male brain" dichotomy, as defined by their culture, they may easily miss other dimensions that are much more relevant to the formation of transgender identities.

    Right now I see some kind of lock-in in this part of the neurosciences. To give one example: Even the researchers who disagree with Ray Blanchard and his autogynephilia-theory are forced to look at the dimensions he think are most interesting (crossdreaming and sexual orientation) when studying trans identities. They have to do so in order to be part of the scientific discourse in this area.

  9. Recent information by neuroscientist Dr.Lise Elliott about how new large research shows the sexes brains are much more alike than different! Three major areas in the brain that were claimed to be different were found to not be different using over 6,000 women and men.



  11. Dr.Janet Shibley Hyde in this 2005 major meta-analysis of hundreds of studies by all different psychologists from decades that was written in American psychologist,the journal of The American Psychological Association,found that the sexes are more alike than different in almost all personality traits,abilities,etc.

  12. In these extensive studies by psychologist Dr. Janet Shibley Hyde and others that is still on the American Psychological Association's web site since 2006 and that was published in American psychologist the journal of The American Psychological Association,Think Again:Men and women Share Cognitive Skills.

    It's reported that Psychologists have gathered solid evidence that boys or girls or men and women differ in very few significant ways-- differences that would matter in school or at work--in how,and how well they think.

  13. Thank you very much, Randie! These are very useful resouces.

    So what we see is that all in all men and women -- on average -- share the same cognitive skills and abilities. This probably means that (most of?) the differences we see as regards interests are shaped by culture and the need to have your gender identity affirmed by others.

    But again, that does not mean that there is no such thing as a biologically based gender identity that drives people (trans or no-trans) to seek out such affirmation.

    I suspect that the researchers have been looking in the wrong place. Due to the gender stereotypes that even permeate the scientific circles, they have been looking at complex, cognitive, skills. I suspect what drives gender dysphoria lies much deeper in the psyche, which may explain the strong sexual component of crossdreaming.

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