logicprog 3 months ago

So a [gigantic meta analysis](https://www.sciencedirect.com/science/article/pii/S014976342...) of thirty years of studies on sexed structural and functional differences in human brains found zero evidence of any differences, a completely overlapping distribution, but as soon as "big data AI" is used suddenly not only are there differences, there's literally zero overlap? Count me suspicious. I think I'm going to trust the meta-analysis of 30 years worth of wide-ranging scientific study over the brand new study that's just throwing whatever fad is currently in the vogue at the problem to see what happens.

  • cmcaleer 3 months ago

    I have to assume you haven’t bothered reading this, because section 2.3 points out flaws in the methodology of the studies looked at which the methodology in this study kind of tries to address (whether or not it’s a good job of it is left for everyone else to figure out). You shouldn’t dismiss a result out of hand because it doesn’t fit preconceived notions, but it’s absolutely a reason to try to dig in to the methodology of the new study and make sure it’s not flawed.

    That said, this meta-analysis is also filled with some crazy statements. It seems to imply sexual dimorphism is only really visible in repro organs but women necessarily need to have wider hips to facilitate child birth among other differences.

    This obvious point should have also been noted when comparing differences in organ mass, since mothers of babies with larger heads are more likely to die so this is selected against. Not an issue with lungs, heart etc., hence larger % differences in sexes there.

    These aren’t egregious omissions in and of themselves, but it’s certainly useful context I’d like to have were I not familiar with sexual dimorphism.

    The dismissiveness of a 1.6 fold increase in SDN size of human males compared to human women is bad. That’s enormous! Not something I would prepend with “only” and repeatedly call “small”, even when not comparing the differences between M/F humans and M/F rodents.

    Bizarre that none of the authors objected to this phrasing, because it’s poisoned reading the rest of this paper for me. How am I meant to trust the authors’ opinion of what a “small” difference is?

    Some of the points are a bit more compelling, like in section 5.1 where they point out that a difference attributed to M/F was replicated in much smaller size by concentrating on volume instead, or in 5.2 where they point out a few papers that missed crucial nuance.

    But overall after reading a few thousand words of this, the nicest thing I can say about it is that I agree that it is indeed gigantic.

  • logicprog 3 months ago

    Update: had a friend with access send me a PDF of the study and looked through it. It seems that the big breakthrough is only half AI — the other half being looking directly at time series of fMRIs instead of static images with features in them manually selected for relevance, because how the various circuits in the brain operate and circulate over time is important information. Also they got this to replicate well with the same people at different times, and also generalize to two other cohorts, consistently, and also used XAI to check what the AI was keying off, to make sure it wasn't going off something nonsensical, and directly used those features with success as well. It seems like an extremely carefully controlled and designed study tbh.

  • courseofaction 3 months ago

    Without making any claims about gender or non-binary people (not my wheelhouse, I simply don't know), there's ample evidence to suggest statistically significant population-level differences between males and females on a many cognitive measures.

    I don't see how it's surprising that an new generation of signal-detection tool finds population-level differences in the brains that produce these cognitions.

  • derbOac 3 months ago

    I think the linked news article is a little misleading, although I share your skepticism. I'd like to see these results replicated rigorously on still new sets of data by independent researchers; I wouldn't be surprised either way, if the results did or did not replicate.

    However, the news article seems to spin this as "male and female brains are totally different entities that bear no relationship with one another." Although I haven't reread it carefully, it seems like the article is saying something more like "you can identify gender-specific patterns, and those gender-specific components relate to things like cognitive ability gender-specifically". It's not that you can't find overlap — that that wasn't the focus of the study — it's that if you go looking for differences, you can find them.

    • RoyalHenOil 3 months ago

      It seems to me that in order for male and female brains to be functionally the same, they would need to be physically different to account for the extreme hormonal differences.

      When you give a man a female dose of hormones or a woman a male dose of hormones, it has a very big effect on their mood, behavior, and mental wellbeing. This change is much, much bigger than the average diffences we see between men and women. For example, an average man with an average woman's level of testosterone will experience a MUCH higher level depression, listlessness, and sexual disinterest than the average woman experiences.

      This strongly implies that human brains must correct for these huge hormonal differences. Basically, in order for male and female behavior to be similar, their brains must differ. If their brains are the same, then hormones will have a much, much bigger influence on male and female behavior than what we actually see in reality.

      Hormone-correcting brain differences would also imply that it's possible for people to be born with some type of intersex brain condition, and that these individuals would benefit greatly from receiving hormone therapy to bring their hormone levels in line with their brains. And this, indeed, seems to be something we see occasionally.

      (In case anyone cares or thinks it is relevant, I wish to note that I am a cisgender woman and I do not think that there are huge innate differences in men's and women's mentality — certainly nothing like on the level that testosterone/estrogen/etc levels would predict. I think most of the differences we do see are environmental, which is why these gaps have been closing in recent history — or widening in some cases/locations. Based on these trajectories, I suspect that men and women are actually FAR more similar than anyone natively groks, and that we exaggerate or invent small differences due to a biological hyperfixation with sex. Note that we don't obsess about the mental differences between, say, male and female cats, even though they have much greater sexual dimorphism than humans do.)

      • rcxdude 3 months ago

        > For example, an average man with an average woman's level of testosterone will experience a MUCH higher level depression, listlessness, and sexual disinterest than the average woman experiences.

        Is this true even if they were to have an average woman's level of estrogen? It may be that the brain needs either set of hormones to work effectively, and doesn't work well when lacking both (of course, gender transition HRT aims for this, but pretty much all undergoing it are trans and so aren't a good indication of average reaction to hormones for their chromosomal sex. And a cis person undergoing the same HRT isn't likely to enjoy the process)

        • empthought 3 months ago

          > Is this true even if they were to have an average woman's level of estrogen?

          They do. They have the average 60-year-old woman's level of estrogen.

          • logicprog 3 months ago

            And even cis women notoriously feel shitty with that little hormones of either kind in their body.

  • ars 3 months ago

    When your study contradicts reality, your study is wrong. That there are major mental difference between men and women is obvious to anyone who interacts with both.

    If your study can't find those differences it's your study that's wrong, not that the differences don't exist.

    • logicprog 3 months ago

      That's interesting. So if a study is counter intuitive to "common sense," it's the study that's wrong? Especially since they're talking about structural and functional neurological differences, whereas the "everyday common sense" differences you're gesturing at could be due to other things, so they aren't necessarily in contradiction.

      • ars 3 months ago

        > So if a study is counter intuitive to "common sense," it's the study that's wrong?

        Possibly, yes. But "common sense" is a very weak way of describing things here, because common sense is usually used to describe intuition, not knowledge. We are talking here about knowledge - men and women are different mentally, this isn't something unknown, or something requiring a study.

        > since they're talking about structural and functional neurological differences

        Given that there are obvious mental differences, and that most people don't believe in duality, that would imply there have to be neurological differences, if your study didn't find them, your study is faulty. Either that, or it's evidence for dualism.

        • logicprog 3 months ago

          > We are talking here about knowledge - men and women are different mentally, this isn't something unknown, or something requiring a study.

          The whole point of science is to double-check this sort of thing, the stuff "everyone knows" that seems obvious to casual observation, like that the earth is flat. Plus you're simply asserting and re-asserting that this is capital-K Knowledge, without providing any reasons, just banging the podium. That's not very convincing. This is anti-intellectualism.

          > Given that there are obvious mental differences, and that most people don't believe in duality, that would imply there have to be neurological differences, if your study didn't find them, your study is faulty. Either that, or it's evidence for dualism.

          Or maybe the differences are very social and contextual — men and women's brains largely operate the same way and are structured the same, but give different outputs because they're given different inputs — and the impacts of those social and contextual inputs are simply too fine-grained to show up.

          • ars 3 months ago

            If you make a study that finds that plants don't need water to grow your study is wrong. It's like that here, this isn't one of those things that needs extra evidence or debate.

            > This is anti-intellectualism.

            And what epithet would you give to those who pretend there is no difference?

            > Or maybe the differences are very social and contextual

            This is certainly an interesting idea (and one I've heard before). But you have to prove it. You can't just declare "I found no differences, therefor it must be a social difference".

            The standard of evidence to declare this is very high, it requires actual proof not just a well reasoned argument.

            And you will have to somehow explain all the evidence against this - for example in nordic countries they found that if they give the household enough money the wife prefers to stop working, and stay home. This went against their idea that men and women should be paid the same, and supported identically, because then women will want to work. Instead they found women actually preferred to be home, and they only wanted to work if they had to (i.e. not enough money). Men however had the opposite result.

            So their goal of equal employment would require them to reduce support. I'm not sure what the government chose to do.

            > are simply too fine-grained to show up.

            Then your study is faulty and you should declare "invalid study", not "valid study we found nothing".

  • im3w1l 3 months ago

    Sounds like a case of "Old measuring instrument cannot tell two things apart. New more precise instrument can tell them apart"

    • logicprog 3 months ago

      They're using the same measuring instruments, though. They're just feeding them through AI. Maybe, though. Let's see if it replicates.

  • LudwigNagasena 3 months ago

    It’s not the first study to find differences. And that’s not the only meta study in existence. I don’t see why one would be surprised given other literature around the subject.

    BTW, note how the article you cited doesn’t argue against differences between male and female brains but makes a rather pedantic point about “dimorphism”.

grugagag 3 months ago

Im surprised they didn’t find any differences between brains of various men. Or women.

aappleby 3 months ago

"Male and female brains are so similar that it takes a dedicated AI to distinguish between the two."

  • hpen 3 months ago

    Turns out AI is good at separating noisy signals

dopylitty 3 months ago

The article seems to conflate sex and gender while the study is paywalled so I can't tell how they defined male and female. The study does seem specific to sex and doesn't mention gender at all in the abstract.

Without those definitions it's basically saying "things we grouped a certain way ended up grouped that way" which isn't really a useful result.

  • elzbardico 3 months ago

    Really, I understand the human rights aspect of calling people whatever they feel they are and I am all for it. I think we should call people by their pronouns and whatever. Sex is one thing and gender is another.

    But definitely, pretending that innate differences between sexes are influenced by the social construct of gender is going to far into a rabbit hole.

    Let's just accept that we can still have medical research based on sex, and understand that it doesn't invalidade the idea of gender. It is just a different matter.

    • AndrewKemendo 3 months ago

      That’s making a pretty big assumption that external factors are non-causal in the expression of genes that impact gender

      We know for a absolute fact that genetic expression is environmentally impacted - To the extent that even eukaryotic organisms can change sex based on environmental factors

      So it’s not implausible that environmental factors actually do affect human genetic expression of characteristics that we typically consider gendered

      • elzbardico 3 months ago

        I am not assuming this, but the point is that it is perfectly valid to keep doing studies on the fundamental and pretty well-understood phenomenon of birth-sex and whether it is a significant causal factor on the biology of homo sapiens.

        It is a simple variable, we can start from it and then try to see whether gender self-identity has any effect.

        We can be pretty sure of the sex-at-birth of any human being given some simple tests. It is a simple variable that we can trust have been correctly recorded the vast majority of time. Gender identity? not so simple.

        And given a correct understanding of the differences, if any, between sex-at-birth individuals, we will have a good framework from which we can investigate if those differences follow gender identity, and if so, what is their causal relationship with gender, etc. etc. etc...

        What I am questioning, is that if every time a scientist do a sex-at-birth based study we question implicitly if they are not being bigots, we will end up censoring scientific inquiry for no good reason at all. (yeah, I do believe that not all scientific inquiry is allowable, for example, I oppose research on chemical and biological weapons)

        • zgjead 3 months ago

          Gender identity is a fairly recent cultural invention too, it just started out as a euphemism for the desire to be the opposite sex, or, more commonly, some stereotyped idea of the opposite sex.

          In a culture without such polarized ideals of how males and females should behave and present themselves, the concept probably wouldn't exist at all.

        • AndrewKemendo 3 months ago

          “Fundamental” is carrying too much weight in your argument

          You’re supposing that the binary classifier is the most accurate starting point.

          I’m suggesting that you should assume that this is a biased starting point and shouldn’t have any power as a benchmark or reference frame in any dimension

          The same way we don’t use ideas like humors anymore because they are based on bad assumptions

          • Supermancho 3 months ago

            There are characteristics that must be paired to produce offspring. The starting point has utility in at least 1 fundamental way.

          • elzbardico 3 months ago

            A long time ago I wanted to be a medical doctor, but humanity somehow dodged this bullet (luckily, may I say) and I quit medical school just before the third year (the fact that programming computers paid my bills, while medical school did not at the time may have been partially responsible for this).

            So, I am no medical doctor, but I was a pretty diligent student, and given the few things I studied about human physiology, I can assure you that biological sex is a pretty much fundamental fact for species that propagate via sexual reproduction, something that I can provide some anedoctal evidence being an homo sapiens, and being one of the parents of a certain number of other homo sapiens.

            Maybe it is not as fundamental as the measurement of whether someone have a pulse or not at the present moment, or if their core temperature is around 36C, but it is still really consequential. Indeed, sex is far more consequential than something like race, which basically is mostly irrelevant for medicine.

            You see, the problem with your analogy, is that humours was not a theory really based on the systematic observation of reality. Once we could measure more and more things empirically, it was pretty clear that it was a crackpot theory.

            And while in a sense, you may be right and someday we could come up with new scientific facts that showed that the whole edifice of sexual reproduction would be superceded by new, better scientific concepts, the fact is that this has not happened, and frankly, it doesn't look even remotely likely to happen.

            Until the day we have an alternative scientific theory, with predictions that can be reliably reproduced on experiments, and that explain such foundational biological issues such as human reproduction and secondary sexual characteristics, sex continues to be a very useful category of study.

            Indeed, even the medical field of gender reassignment treatment relies heavily on the corpus of knowledge based on the concept of sex in things like hormonal treatment and puberty blockers.

      • liveoneggs 3 months ago

        apparently whatever brain patterns being measured here are not on that list of factors

  • Flemiklo 3 months ago

    I would assume that the hormonal effect on a brain is a lot more relevant when looking for brain forms than like social constructs.

    We are not able to tell if someone is a logical person or a cool dude or whatever just by looking at it.

    And apparently hormones don't make a brain look different either

    • Supermancho 3 months ago

      This may be of interest. https://youtu.be/8QScpDGqwsQ?si=mTXWvzZKJO0RsAiA

      Neuro-biology of trans-sexuality : Prof. Robert Sapolsky

      • arthurwong 3 months ago

        When is that video from? The studies he mentions, of BSTc and INAH-3 nuclei, are from way back in 1990s and early 2000s, and there has been much research since which disputes the stance he's taken in this video. Specifically, when researchers controlled for sexual orientation, there was no cross-sex shift in brain structures that correlated with transsexuality.

  • dryanau 3 months ago

    This is a lazy take.

    • hpen 3 months ago

      Says the guy who leaves a one liner explaining his take

mouse_ 3 months ago

Interesting. Would also like to see a similar study conducted among non-binary and gender nonconforming people.

  • Javalicious 3 months ago

    Looks like they _might_ have been in the study set, but weren't separated out and focused on? At any rate, the author is hoping for the same:

    "In the first edition of my book Why Gender Matters, published by Doubleday in 2005, I devoted a chapter to kids who are psychologically “gender-atypical.” I suggested that these kids are somewhere in between male and female. But the Stanford study provides little support for that claim. I am hopeful that the researchers will do follow-up studies specifically looking at individuals who are gender-nonconforming, gender-atypical, and who have gender dysphoria, to see whether and how those characteristics influence these findings."

  • liveoneggs 3 months ago

    the sample was "roughly 1,500 young adults 20 to 35 years of age" so, in today's environment, I don't think it's possible that there were not at least a few who self-identify as non-binary and nonconforming.

    • riskable 3 months ago

      Transgender folks are represent about half a percent of any given population. So if the study had 1500 participants that would mean ~7 were transgender.

      If you look at the graphs from the study those people could be the outliers but no matter what, it's not really enough people to glean anything useful.

      • empthought 3 months ago

        > Transgender folks are represent about half a percent of any given population

        This is not accurate for the cohort under study. 5% of people under age 30 identify as transgender or nonbinary. I would personally be unsurprised if well over 100 individuals in the study identified that way.

        https://www.pewresearch.org/short-reads/2022/06/07/about-5-o...

        • rachofsunshine 3 months ago

          You have to be a little bit careful with those kinds of numbers. Once you get down to a few %, actual signal starts to be swamped by troll answers, misclicks, and other sources of error. You'll basically never see a number below a few percent in any poll with a decent sample size.

          (As an aside, this is one of the things that makes the data on the effectiveness of transition care more remarkable than it even looks. Given the very high probability that a random person is cisgender, even moderate false-positive rates would swamp true-positives. The fact that they don't suggests false-positives are very rare indeed.)

          • empthought 3 months ago

            This is a Pew Research study…

            • rachofsunshine 3 months ago

              What's your point? Looking at their methodology [1], it's pretty clear those sources of error would still be an issue here:

              > The American Trends Panel (ATP), created by Pew Research Center, is a nationally representative panel of randomly selected U.S. adults. Panelists participate via self-administered web surveys.

              [1] https://www.pewresearch.org/wp-content/uploads/2022/06/trans...

              • empthought 3 months ago

                0.5% (as the original poster opined) is not within the 95% confidence interval of the survey. Anywhere as low as 3.2% or as high as 7.8% is within the confidence interval. I am not sure why you would knee-jerk dismiss this.

                My point is that it is reasonable to expect between 3% and 8% of the MRI study participants to have been trans. It is not reasonable to think that 0.5% or less would have been trans.

                • rachofsunshine 3 months ago

                  Confidence intervals account for _statistical_ error in which members of the population you happened to survey, not for incorrect data collection like "people randomly select the wrong button sometimes".

                  I'm not dismissing the claim as false, I'm saying that surveys like this are poor evidence that it is true because they are not very good at making precise statements about rare subgroups.

                  • empthought 3 months ago

                    I don't understand anything you're saying here. It seems to be denying the validity of any survey methodology, no matter how experienced and legitimate the survey-taker is.

                    Should I doubt that there are really around 5 million religious Jews in the US, because the Pew survey used to estimate this could have had "people randomly selecting the wrong button?" Should I hold it equally likely that there are a mere 500,000 religious Jews? This subgroup is far more rare than the subgroup of 20-35 year olds that identify as transgender or nonbinary. How can we know anything about this subgroup at all, since (according to you) surveys cannot constitute good evidence for anything for a group with such rarity?

                    • rachofsunshine 3 months ago

                      The "survey-taker" here was the people being asked. It wasn't administered by a human surveyor; people were completing an online form. I just went and looked at our online signup form, and I've had to collect entry errors on three of the last twenty submissions.

                      If the only source we had for the percentage of the population that was religiously Jewish was a poll, then yes, I would say you should take that number with a hefty grain of salt. But that isn't the only data we have. We have data from many polls, the census, back-of-the-napkin estimates based on the number of places of worship and average attendance, past demographic knowledge, fertility rates and immigration, and so on.

                      Even then, there's substantial error in those estimates - the US Census Bureau itself, arguably the most sophisticated demographic operation in the history of mankind, estimates that they double-counted ("erroneous enumeration") roughly ten million Americans, shrugged and went "yeah someone probably lives there" ("whole-person imputation") for another eight million, and missed eighteen million [1]. And that's just for total population (they think the error is larger among subgroups).

                      And numbers for trans people are highly variable (by as much as 1.5 orders of magnitude) among major sources I'm aware of. For example, the Williams Institute [2] finds ~1.5% trans ID among young people (a third of Pew's number), and binary trans people outnumbering nonbinary ones 2:1 (inverting Pew's ratio). The Canadian census shows <1% [3] among young people.

                      And corroborating sources are harder to get, both because there's a lot of disagreement about who exactly "counts" (Pew uses "transgender" and "nonbinary" as separate categories, the Williams Institute considers the latter a subset of the former) and because corroborating evidence is often only available for subsets of the population (like people who sought medical care related to their identity).

                      So yeah, I stand by what I said: a single survey does not tell you very much about a rare subgroup, in this or any other context. It is data, but it should be taken with a substantial grain of salt, especially when it comes to a group like trans people whose boundaries are fuzzy and highly controversial even internally. Certainly I don't think the statistical MOE tells even close to the full story, since it doesn't even for MUCH simpler questions (typical polling error in elections is ~twice the MOE on a much more clearly-defined question, for example).

                      [1] https://www.prb.org/resources/how-accurate-was-the-2020-cens....

                      [2] https://williamsinstitute.law.ucla.edu/wp-content/uploads/Tr...

                      [3] https://www150.statcan.gc.ca/n1/daily-quotidien/220427/dq220...

  • astromaniak 3 months ago

    The difference has two components: genetic, personal. Genetic does not depend on self identification. Personal is very similar these days. Same families, same schools.

    As for trans. Humans, unlike most animals, cannot even have sex without being taught. The reason is humans for many generations, million years probably, lived in groups and learned how to do it. Those who didn't have genetically hardcoded knowledge how to make kids by the time they grew up they knew it any way. It wasn't necessary and with the time it was almost lost. The same with gender identification. Everywhere boys and girls where brought up differently. So, we lost hadcoded self identification. Today human kids may grow up thinking they are dogs, or wolfs, or sheep. If they happened to grow up with animals.

    Conclusion is it's parents responsibility to give kids the right identity. Failure to do it, some brainwashed wokes don't do it intentionally, results in miss self-identification. Add to that 'doctors' multi-billon industry preying on them and some schools playing along to keep parents uninformed. There was a couple of months back interesting article about navy seal who had mental problems. He was brainwashed into believing he was a woman, and needs treatment and surgeries, payed by government. Later he realized he was just used to make money, and became a man again. The same happens to kids en mass. Because they are easy targets.

    • Flemiklo 3 months ago

      That's a lot of weird nonsense.

      We do not know what influences the way brains choose some kind of identity.

      And obviously we as a society created this stark contrast between male and female. Look at animal kingdom

      • trealira 3 months ago

        > And obviously we as a society created this stark contrast between male and female. Look at animal kingdom

        How so? Many species of animals show sexual dimorphism.

        • astromaniak 3 months ago

          yep, chimpanzees are an example. we were one specie 7 mln year ago. so, it started long before humans separated from animals.