[HN Gopher] New Research Finds Differences Between Male and Fema...
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       New Research Finds Differences Between Male and Female Brains
        
       Author : janandonly
       Score  : 28 points
       Date   : 2024-07-08 17:21 UTC (5 hours ago)
        
 (HTM) web link (www.psychologytoday.com)
 (TXT) w3m dump (www.psychologytoday.com)
        
       | mouse_ wrote:
       | Interesting. Would also like to see a similar study conducted
       | among non-binary and gender nonconforming people.
        
         | Javalicious wrote:
         | 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 wrote:
         | 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 wrote:
           | 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 wrote:
             | > 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 wrote:
               | 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 wrote:
               | This is a Pew Research study...
        
               | rachofsunshine wrote:
               | 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 wrote:
               | 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.
        
         | astromaniak wrote:
         | 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 wrote:
           | 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 wrote:
             | > 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.
        
       | logicprog wrote:
       | So a [gigantic meta analysis](https://www.sciencedirect.com/scien
       | ce/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.
        
         | im3w1l wrote:
         | Sounds like a case of "Old measuring instrument cannot tell two
         | things apart. New more precise instrument can tell them apart"
        
           | logicprog wrote:
           | They're using the same measuring instruments, though. They're
           | just feeding them through AI. Maybe, though. Let's see if it
           | replicates.
        
         | courseofaction wrote:
         | 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 wrote:
         | 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 wrote:
           | 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 fairly often.
        
         | cmcaleer wrote:
         | 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 wrote:
         | 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.
        
       | aappleby wrote:
       | "Male and female brains are so similar that it takes a dedicated
       | AI to distinguish between the two."
        
         | hpen wrote:
         | Turns out AI is good at separating noisy signals
        
       | dopylitty wrote:
       | 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 wrote:
         | 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 wrote:
           | 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 wrote:
             | 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 wrote:
               | 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.
        
         | Flemiklo wrote:
         | 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
        
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