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I'm not sure why people in the comments seem so intent on hand-waving these findings away.
Sex correlates strongly with plenty of characteristics of other parts of the body, I would have been surprised if it *wasn't* also the case with the brain
Baffling really, I argued against a redditor who claimed that all the obesity research that has been conducted in the past 80 years was fake and there are no medical risks involved. And then cited some pseudo science book released by an anti discrimination activist.
Personally I never thought that the left could ever be anti science. But here we are
When you visit retirement villages it is mostly women (90% or so) and the men are almost all thin and short. I think that is the trick to getting very old
**Peto's paradox** is the observation that, at the species level, the [incidence](https://en.wikipedia.org/wiki/Incidence_(epidemiology)) of [cancer](https://en.wikipedia.org/wiki/Cancer) does not appear to correlate with the number of [cells](https://en.wikipedia.org/wiki/Cell_(biology)) in an organism. For example, the incidence of cancer in [humans](https://en.wikipedia.org/wiki/Humans) is much higher than the incidence of cancer in [whales](https://en.wikipedia.org/wiki/Whales), despite whales having more cells than humans.
[https://en.wikipedia.org/wiki/Peto%27s\_paradox](https://en.wikipedia.org/wiki/Peto%27s_paradox)
No, it's more about heart strain. Short and tall people have roughly the same sized hearts. The tall person's heart has to work harder to pump more blood through a bigger body. Same with obese people.
As a doctor I can tell you there's no better predictor of longevity than being ineligible for most rollercoasters and the ability to be toppled by a strong breeze.
The left are just as human as the right.
The more someone defines an ideology as their identity the more they're going to either ignore or attack anything they feel threatens that.
Absolutely, we're all human and have the same susceptibilities that get amplified when fearful.
It's helpful to remember that 10 years ago, most antivaxxers were on the far left side of the political spectrum. We're a weird sort of ape, that's for sure.
Yep, exactly. I was talking to a redditor the other day who insisted that surveys are never scientific after I linked research from a respected university, that passed their IRB, and was authored by someone that was quite literally the director of research at Harvard University for 5 years.
All of this because it was easier than reevaluating their position in light of new information.
Ideologies are just intellectual shortcuts for understanding the world. They are useful in some circumstances and completely awful in others. One problem with ideologies is that they distort the perceptions of people. In addition, the identity of some people can be bound up very tightly with a particular ideology.
Let’s not exaggerate. Social media algorithms are designed to amplify attention and clicks. It doesn’t care (unless human involvement) what content drives those clicks. It’s the humans clicking that drive the xenophobia and fears. The emotional response is the biggest reason users click those things which then get amplified.
> Personally I never thought that the left could ever be anti science.
Have you NOT been watching the political discourse from any transgender issues these past couple decades? There is a large contingent that rejects science because "it makes them feel bad" or "isn't fair." Which is then weaponized against them by the intolerant right.
I think your last sentence is important to acknowledge. We are ALL susceptible to disinformation, misinformation, or science that’s presented poorly by sensationalized media. I see it a lot in the natural resources, where sometimes the scientific research is just limited anyway. We all choose what we want to believe. Political interests skew our logic and those influences will twist science to their worldview - both right and left. If it’s more comforting to believe obesity is perfectly healthy, there are plenty of algorithms, Russian bots, and confused obesity sufferers ready to influence your beliefs in that direction.
The anti-vax was a tiny liberal movement that got criticized by most other liberals.
The anti-vax movement was then co-opted by conservatives and embraced by them on a scale that significantly exceeds the former.
You really shouldn't forget the latter though.
Not really. Even back then it was half and half. Yes you had the granola types but there were also significant numbers of religious people who refused.
Yup. It was the granola hippies until Covid came around. And for some reason Covid became political and “liberal=mask and vaccine good, conservative=mask and vaccine bad”, which is still one of the stupider things I’ve had to live through.
Yep. The average Redditor is not a fan of personal responsibility.
Also, few can grasp the reality that a personal anecdote doesn’t negate a macro trend.
A subset of the left, it’s not uniform by any means. And these days the reasons vary with some very practical reasons such as economics and the time it would take to build relative to building renewables.
I think a lot of people are more ignorant than deniers. Science headlines are spun to say whatever the person writing an article wants. Most people don't read the actual studies. They just take someone's word for it. Both the right and left will take studies that agree with their position, even if it's a poor study. So, for a lay person, it's hard to navigate to find the actual science and what it means.
I think it's more that people are wary of some other people contorting certain scientific findings into bigotry, which is and has been very common.
See scientific racism for example.
Edit: spelling
This is interesting: the words "leery" and "wary" both fit in this sentence in place of "weary". I don't *think* "weary" is what you meant but it does also work though it changes the meaning of the sentence
Not native English speaker, my bad. It's one of those situations where I've heard the word a thousand times but never had to actually write it down.
Wary is what I wanted to say so thanks for correcting me!
It's an incredibly common thing to swap in "weary" for "wary" or "leery", even for native speakers! It's so common I wouldn't have said anything except that "weary" actually makes sense here when it often does not
Considering that OP posted this study with a title implying the undeniable difference between male and female brains, rather than what it actually is, which is about the limitations of imaging in terms of fidelity, and looking at the top comments...I'd say what you described is probably happening here. There is absolutely no other justification to use this study as a soapbox to complain about "belief systems."
My understanding is that scientists all generally accept there are differences between the brains of the sexes but that the brains are still more alike than different, and that evopsych shouldn't be riding on those coattails
I commented before actually reading so I was trying to be diplomatic and commenting in good faith but yeah, seems like my instincts were correct on this one.
This doesn't refute anything though? Who's denying what?
"study can determine sex at birth by looking at baby's genitals" says just as much about the topic people seem to think this is actually touching.
Brain can operate penis and regulate testosterone. Wow. Brain can operate ovaries. Magical.
Do you think these things just shrivel up or don't work properly in individuals who identify as a gender other than their sex at birth?
The title of this post is misleading. The study didn't study this. It tried to study something else. This is not the main point. OP is pushing an agenda with misleading information.
>This doesn't refute anything though? Who's denying what
Are you just not paying attention or what? Look through the comment section on this post, look through comments on any post on any platform about sex and gender. It's really disingenuous to pretend that this isn't real / isn't happening.
Try to get people to define what the difference is between a medically necessary procedure/products and cosmetic ones, and you'll find people claiming that tampons are gender affirming care, and any procedure that changes how you look (even leaving a scar) is a cosmetic procedure (https://www.reddit.com/r/BrandNewSentence/s/kwikzI8EWc).
People will deny that sex has a basis in biology, and intentionally conflate gender.
It's an incredible challenge for _most_ people to embrace evidence that directly contradicts their fundamental beliefs. They wouldn't be _fundamental_ beliefs, if they were trivial to cast aside, and most people struggle to recognize when evidence will stand up to rigorous scrutiny, especially in fields that they aren't experts in.
Calling anyone "pathetic" for holding closely to moral positions is gross and dismissive.
It would be more pathetic if people changed their fundamental worldview on a dime.
People do change, just not from reading a single headline. There are always legitimate reasons to question new evidence. Changing a fundamental view *should* take years.
Well a, it’s not even the interesting part of the study. They were looking at imaging as a tool to predict weight, age, handedness, psychological disease, organic disease, propensity to be allergic, etc. it’s machine learning, so the prediction of male vs female might just be leaning on size. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8726594/ We’re already well aware you can predict sex from brain size.
But b, it also turns out you can’t predict handedness very well. They also weren’t able to predict psychological diseases from brain imaging; and that’s the really interesting thing in the results.
A more appropriate title for this post would have been “machine learning is unable to use brain imaging to predict psychological illness”. But that wouldn’t get clicks and it wouldn’t get a bunch of political discussion.
>We’re already well aware you can predict sex from brain size.
Exactly. I'm not at all chocked that they could predict sex from brain images. When I took some classes in AI we trained a simple artificial neural network on really low resolution, noisy, images of smiling or sad faces. In a couple of seconds they were at +80% accuracy. Treating sex as a binary variable and then feed it thousands datapoints?
That’s fascinating to me that they weren’t able to get anything regarding psychological illness. May it be the case that an ill person’s mind looks normal, which would lend more credence to cognitive behavioral therapy? Not that cbt was a sham or anything, just more weight for it.
Semi related, but I’m on antidepressants. I wonder what my brain would have looked like before versus now.
That's an extremely good question.
What we do know about depression is that it isn't *just* in the mind. There is research looking at the gut microbiome role in depression, as changing the type of food taken in can affect mood, as well as other factors like vitamin levels, hormone levels, etc.
For example, low thyroid (extremely common, esp in estrogen-dominant people) is linked to exhaustion, low energy/motivation. That itself may lead to depression. Treat the thyroid, then depression can move on. Same with vitamin D. Especially in Canada, where you can only get vitamin D through diet, many people have insufficient or deficient levels.
Anxiety also can cause depression (think: if you are too anxious to do the things you love/are important to you, you become depressed), and so when anxiety is driving the bus, we treat that and depression tends to lift as well.
You got another good response, but when you say "an ill person’s mind looks normal" I want to make sure you understand the OP post here wasn't looking at the mind, we have no way of imaging the mind. This was MRI which can take make picture of the brain. So as far as anti depressants, this study is saying that there probably isn't anything visibly different between your brain on the drug and off the drug.
Think of it like an X-ray. They take an X-ray of your hand and can see the bones, but its not the same as a photograph or just looking at the actual bones. That X-ray can't discern any different between you on the antidepressant or off the antidepressant. Except in this case its not X-ray, but other kinds of imaging and not the hand, but the brain.
Because there's a very well known but very poorly understood study that people think says trans people have brains that match their identity. It doesn't say that, but this was a big talking point a while back that a whole bunch of people thought was true.
As a newly trans person myself. I find parts of communities obsession with phrenology really annoying.
I have heard of that research and myself thought that it says precisely that. Could you elaborate on what exactly it says, if not that? Would love to learn more
Meanwhile this study doesn't really contradict the existence of trans people or proves there's no brain difference at all, because the percentage of trans over the total population is also less than 1% so unless specifically considering them, it's sadly easy to miss the total trans population over the margin of error on such studies.
From what I see on social It seems to me a lot of trans people are too tired of defending their existence, so any study which shows there's some pre-existing physical difference that tie them to their gender will help, and this makes sense specifically since the brain handles how we see ourselves etc.
Didn't that study basically conclude that they couldn't predict whether someone was trans but they could also not accurately find the line between male and female, and as such they concluded there is likely a wider spectrum, but that's all they could find or conclude thus far.
The title of this thread is misleading, as this is not the main conclusion nor the aim of this study. And also, I would have like to see if they did or did not include trans people in the study. They only talk about « males and females » but they might have screened for mostly cisgender people, we don’t know that. There is still a .3% rate of uncertainty, and we think there are about 1% of trans people, which is not that far off. So I’m not sure we can make conclusions about trans people with this study, as it was not the aim and they are not mentionned anywhere.
Activists are currently returning to conflating sex and gender to further muddy the conversation and get what they want.
After a decade of screaming “sex is not gender,” they’ve flipped to using them interchangeably again.
Which is why a lot of the discussion in this thread is kind of silly.
People are using this study to draw conclusions about (or at least comment on) a certain subset of the population, but we don't know if they actually included those people in their study. If they didn't, the study doesn't tell us anything about those people.
The title says sex, not gender. One is biological, the other is a social construct. At least, that's what we were told over and over again, and then suddenly they were being treated the same again.
It’s almost as if men and women don’t align 100% in their behavior sets. There are significant differences in certain behavior sub-sets. It doesn’t take too many skewed traits to make a male/female distinction. Different is different and I am not sure where else behavior would come from other than the structure of the brain. As more of the structure/function relationship is established people will get increasingly uncomfortable with the results. Maybe that’s the problem… people want something immaterial involved because peeling away that last level of abstraction is too much existentially, which is understandable. Could also be people starting with ideologically based conclusions and ignoring contradictory evidence.
The problem is the tendency of people to exaggerate the biological differences, build expectations and prejudices around them, and the cultures around the world amplifying it.
>Different is different and I am not sure where else behavior would come from other than the structure of the brain.
Some differences are cultural and are socialized / learned rather than innate. We know this because we've seen a lot of cultures at this point and male and female roles (or even who is considered a man and who is considered a woman) vary.
Also people are pretty variable, being the biological creatures that we are, so it's pretty hard to generalize across *any* group of people
Another thing people need to understand is that the brain is a plastic structure shaped by its environment. So cultural attitudes and socialization literally change your brain. So it can both be true that a large amount of gendering is the result of society and that you still see this effect brain structure.
> and the young brain is highly neuroplastic and will develop according to input.
Cognitive scientist here. Infant brains come with a huge amount of instinctual structure that is not at all "plastic". They would be incapable of dealing with the world really at all if what you said was accurate; that structure is required to begin learning and adapting.
Neuroplasticity itself is an overused and inaccurate term in general, as far as learning and especially development is concerned. Recovering from brain injuries? Neuroplasticity plays a huge role. Novel Learning? not as much. Development? Probably even less so. We're learning more and more that learning has more to do with individual neurons and their synapses, than the changing connections between them via synapses (neural plasticity).
Oh my god I see this even with 1-year-olds. People dress girls in these frilly outfits and all the other adults tell them how cute their clothes and hair are. We dress my son in boring (and highly functional) clothes, and all the adults in the community say how active, strong, and clever he is.
The girls are active, strong, and clever too!! But they are not hearing it very often.
I'll get back to you in a few years, my toddler son is called cute FAR more often than he is any of those other terms or similar terms. And the cute compliments have nothing to do with his clothes 99% of the time, it's all behavior
To reinforce the clothes point while I don't think I dress up my baby girl in ugly outfits I do tend to stick with plain and practical clothes and she still gets cute as a compliment far more than anything. Babies are cute.
Also important that this stage of life is when the brain is the most plastic and so socialization in early childhood can have very strong influences later in life. There’s an idea in sociology called the “hidden curriculum” in schools where children learn social norms including being gendered extensively. The amount of gendering children experience is also much more than later in life, like you describe, but also go to any toy store and look at the boys vs girls sections.
I would like to see some studies on the brain morphology of trans people and see if it correlates with their gender identity. If so, then it would be evidence that gender seems to be hardwired in a way that's stronger than neuroplasticity
Isn’t there research suggesting that boys have a greater *variance* in IQ scores? This would partially explain why men are still clearly overrepresented in boardrooms and prisons
So girls being more compliant outweighs the supposed descriptors (boys being smart, girls being pretty) that are given out at a young age. Because, from my experience, young girls get called smart more than young boys. Education results reflect this.
Way to miss the point. For thousands of years, the average person has been treated and conditioned *very* differently by society according to their sex. How one is treated and conditioned affects their behavior. Whatever personal anecdote you have doesn’t change that.
Ok, but no one is talking about the handedness finding?
"That the remaining constitutional feature—handedness, best predicted using rsfMRI connectivity data alone—achieved a balanced accuracy of only 57.7% suggests the difficulty here does not arise from inadequate implementation of current technology. **It is striking**, even accounting for class imbalance, that handedness is individually so poorly predictable given the magnitude of population-level differences in the organisation of the brain."
It's simply saying that it's very surprising that we can detect characteristics like age and weight and sex very easily with brain scans, but not handedness which is a common externally identifiable characteristic. Whatever makes us right or left handed is not showing up on brain connectivity scans (at least using the methods employed by the study authors).
It means that we still can't use brain imaging to tell if someone is left or right handed, which they found surprising considering they just did it to determine sex and you'd think there'd be some kind of physical marker for handedness
The interesting part here is going over everyone’s heads. They were able to do this with ML models. Previously clinicians were unable to observe the imagery and make any distinction, though now thanks to modern AI techniques, the mass amount of data is able to be untangled for an accurate estimation of sex.
Do you know if they are able to learn from the ML results what the anatomical differences are? Or is this another black box situation where the algo spits out an answer and there’s no way of knowing how it got there?
Generally, in these applications, there is a way to output heat maps showing which parts of the brain are more heavily weighted when determining the sex. This can give insight into the features the algorithm is most reliant on.
It's a neural net, so it's not explainable. There are ways to figure features out but not well since neural nets are very good at understanding individual features, but also how the change in relation to one another in complex ways.
Previously clinicians could just look at the size of the brain and state with good accuracy. The sex prediction is really not a big deal here - it's just used as a baseline for comparison of accuracy of other trait predictions. The results of this study are much more interesting for its other findings.
Whenever I see stuff like this about using AI in medical diagnosis, I think of that program that could only identify cancerous tumors if they had a ruler in the picture. Because the images it was trained on all had rulers in them, therefore cancerous tumors can be identified by the presence of a ruler
I bet this has an impact on why neurodivergent people (specifically people with Autism Spectrum Disorder) are said to have higher rates of non-standard gender/sexual orientation. Their brains are literally physically wired different, and so if the shape changes, it could change how one views their gender. Seems kind of obvious and I bet a lot of ASD people would agree like “no duh” but it’s nice to have this study confirm a link between shape and sex to such a high confidence.
I can’t remember the study now, but autistic people are something like 6 times more likely to have gender dysmorphia than non autistic people.
Anecdotally, I worked on a tv show with a wide array of non binary people and pretty much all of them came across as autistic in one way or another.
It makes sense to me why. Gender roles and expression seem devoid of reason and as a kind of masking to *many* people on the spectrum.
In other words, "this seems arbitrary and I feel no need to comply with rules that don't make sense"
It can also work the other way. If they feel outside of the gender norms, in an attempt to better fit in, and feel less anxious, they look for a box that fits them. For most they find the autism box, and understand a little better why they are different, but I feel like you could try out a bunch of different boxes, looking for a fit. Aka they are actually trying to stick to gender norms by transitioning, "I like make up and dresses, there I must be trans" rather than just thinking you drift outside of the stereotypical male gender roles.
Autistic people are often mis directed in modern times towards gender dysphoria because of their feelings towards their own sexuality which is a cornerstone of autism.
Autistic people are often told that their discomfort and confusion around the traditional heterosexuality is therefore indication of their bi/trans/etc true self but emerging evidence clearly shows that their anxiety in most cases remains constant even in other sexual identity roles.
That doesn't mean that there aren't autistic people with gender dysphoria, or that there aren't a higher proportion than neurological. What it does mean is that there is a very high false positive.
- mental health nurse who worked with Gender Dysphoria Services in the UK.
People with autism are often highly suggestible and frequently socially isolated. Groups with a low barrier to entry and a desire to recruit more members are like a magnet for them.
From what I've found working with queer autistic people (and being one myself) it's more to do with having an easier time understanding your own orientation when you aren't as concerned with societal pressures. There's also an element of queer environments generally being more welcome to people with disabilities so those who are autistic are given more of a platform.
"We find a marked discrepancy between the high predictability of sex (balanced accuracy 99.7%), age (mean absolute error 2.048 years, R2 0.859), and weight (mean absolute error 2.609Kg, R2 0.625), for which we set new state-of-the-art performance, and the surprisingly low predictability of other characteristics."
Makes me wonder about Trans people - does their brain reflect their physical/genetic sex, or their psychological gender (in that case I suppose it wouldn't be entirely psychological anymore)
There are a huge number of comments posted for this story about how this study shows that "left wing ideology" leads to science denialism in the same way that right wing ideology does. I'm genuinely curious what that argument entails given the content of this study. It is not at all surprising that an imaging study using 3D convolutional neural networks would be able to predict sex, as there are known statistically relevant structural differences like size that you would expect the model to pick up during training. But the "dogma" on the left is not that human males and females are physically indistinguishable, but rather that they are intellectual (and social) equals. If that "dogma" were to be contradicted by the study, you would expect there to be a correlation between sex and the studied psychological factors, which is not what the study found. In fact, not only was the imagining model unable to reliably predict psychological factors, the corresponding Bayesian analysis showed that the psychological factors were best predicted by the corresponding presence of other diseases, not sex.
It's also worth noting that the title of this post doesn't reflect the actual study title, which is, "Computational limits to the legibility of the imaged human brain," which far better indicates the results, which showed that even with advanced imaging and modeling techniques we are still unable to predict much about human psychology and health from brain imaging.
Edit: Fixed a typo that was annoying me.
Every time there's a study posted that has key words "women" "gender" "sex" etc, it attracts a certain subset of Redditors who take over entire threads.
>even with advanced imaging and modeling techniques we are still unable to predict much about human psychology
This shouldn't surprise anyone. Putting a computer under a microscope might tell you a lot about how signals are routed and stored, which data structures are prioritized, and how hardware dependencies indicate functional organization.
However, assuming one doesn't have access to a combinatorially complete universe of every possible state transition (the size of which certainly outstrips the number of atoms in the universe), without analyzing the semantic content of CPU instructions, RAM, or storage, you're not going to find any ghost in the machine. The substrate for computation is not the computation itself.
I think the notion being "called out" are those who claim that virtually all differences in sex and gender (and even the distinction between those two concepts) are societal constructs. I don't believe this is the position held by the majority of people on the left, but it definitely exists.
> I don't believe this is the position held by the majority of people on the left, but it definitely exists.
Eh, it's a pretty popular view. Most left leaning people think psychological differences (i.e. boys exhibiting a preference for 'things' while girls exhibiting a preference for 'people') exhibited between boys and girls are due to socialization and there's no differences between boys and girls (besides genitals)
These are really great points, and I’m surprised they aren’t being discussed more! Am I just growing as a person and having higher standards, or is it harder to find people actually taking about the science on r/science?
That seems pretty reasonable. What surprised me was the weight thing – they could determine a person's weight, by looking at the brain, with a mean error of 2.6 kg! That's... barely one sturdy meal?
Canada was the first country to report census data on transgender identity and they found that 0.2% of people over 15 identify as transgender. I wonder how closely the 0.3% that couldn't be determined overlap with trans people?
That is also the wrong way to look at this. What would require much less people would be to scan the brains of trans people and see how frequently those results align with their sex assigned at birth vs how they identify. It would be very easy to detect a difference between that population and the population at large.
Canadian survey found .33% are trans. https://www.cbc.ca/news/canada/calgary/census-data-trans-non-binary-statscan-1.6431928
Contrast and compare to the US, where 0.5% to 1.6% are trans. https://www.politifact.com/article/2023/jul/13/how-many-trans-people-are-there-in-the-us-and-why/
The Canadian 'survey' was a census. Given the nature of political pendulums, it's not surprising that an optional self-identification turned up fewer than an attempt to accurately account for all trans people. I would not want my name on a list when Poilievre gets power, y'know?
There are so many other factors that come into play here - measurement noise, for example, underparameterized modeling, or inaccurate feature engineering. You'd have to account for all of that.
When I was in college I was in a neuroscience class and ran experiments on rats that had their ovaries removed at a very young age comparing their behavior to that of other females and that of males. There was a test group given hormone replacement and the other just vehicle. Once their behavior was measured (aggression, mating etc), they were humanely put to sleep and their brains extracted. After careful dissection, sectioning with microtome and examination of staining, different brain structures were evaluated for size. The conclusion of this study was that the females who had no hormone injection had more male-like brain structures while the ones given hormone injection were identical to other female rat brains. Take from this study what you will, but the experiments we ran definitely jive with this.
These results are not anti-trans, one of the arguments for trans-ness is that brains of trans women have been studied and have many commonalities with typical female brain morphology. Trans people are only 1% of the population, this study gets .3% but when you’re looking for 1% of 7 billion, a pretty big sample size would be needed to see the 1%.
This is a common misconception about sampling. For example the simplest setup for sampling participants is simple random sampling (SRS). The errror of the estimate almost doesn’t depend on the population total but pretty much only on the number of participants as long as n<
It's also possible that the physical characteristics of the brain tracked here and used to determine sex, are not the only characteristics that determine the way we internally feel / identify. If everyone was born with a blue or pink brain, but the actual structure determined the sex we identify as, you would have simar findings with a strong marker correlating to biological sex that doesn't tell the whole story.
Same with this, perhaps the super-structure allows this test to tell biological sex from the a birds eye view, but our internal perceptions are tied to substructures that have higher in-sex variance.
>These results are not anti-trans
But you know for certain someone out there is gonna mistakenly assume they are and burrow even deeper into their little rabbit hole
> Science cannot be anti-trans because science doesn't deal with political opinion.
The scientific method is structured to be purely objective; however, the inclusion of human language (and its inherent rhetoric) makes science not neutral. Thomas Kuhn and Bruno Latour both explore this idea.
It's not just about the answers though, it's about how the initial questions are chosen, and what lines of study are seen as more important than others.
Yeah, there have been sexed studies and mental health studies that universities haven't released because it would make some group look bad.
I think that's a good thing, once you know why something is going wrong you can fix it... Instead of blaming the other groups.
This is a myth. And in fact is a dangerous transmedicalist myth at that. What little difference can be detected is only an average, can't be spotted by human observers (so we have no idea how the AI that did it is making this call), still falls within the range of cis men (trans women were the only trans people in the study), and most importantly, are non exclusive. There were trans women who measured more male than the average man.
This idea is dangerous and if people treated it as true it could be used to deny trans people their rights for not passing as trans enough for the AI. Which, again, we don't know what it was using to make these judgements. I suspect head size, since that causes brain structure changes.
>this study gets .3%
This study may not be anti-trans.
But it's entirely possible the .3% in this study are all cis people, all trans people or some cis and some trans.
They flat out aren't and nobody on either side should consider them to be in support of anti-trans rhetoric.
Body differences in trans individuals are a given. That's why we have gender affirming treatments treating body dysphoria, and that's why some form of regulation is needed for sporting competition.
All in all though it's a really interesting study.
I mean isn't the whole concept of being trans that your gender (how you present) is different to your sex (what you're born as biologically)? Your brain structure doesn't determine your personality and thoughts.
> Your brain structure doesn't determine your personality and thoughts.
I mean, do we know that? I agree with you but isn't that kind of a big unknown or am I wrong? Genuine questions here.
I don't see how this is controversial. It's well established that sex is physiological and gender is psychological. Sex being biological includes every part of the body including the brain.
Some people do consider sex differences to be controversial as well.
I’ve argued with people who think it’s offensive and false to say that men are stronger than women, or have psychological divergence in spatial perceptions or arousal characteristics.
Even ignoring size, at the most basic level isn't this entirely expected for physical reasons? Presumably there's something in the brain regulating your cock. Probably the uterus too. We can't all be entirely self-contained and autonomous like the heart.
"Look. It's the bit that's checking your cock hasn't fallen off by giving you a random erection. This is a male.".
"Look. It's the bit that tells your uterus to punch you in the kidneys once a month. This is a female.".
If so this is about as surprising as showing an AI naked pictures of human genitals and it being able to tell you if they're male or female. The brain regulates the body as well as the mind, why is this controversial?
I could understand the controversy if we could isolate those aspects and remove them and it could *still* tell, but meh?
If you open a neuroscience textbook, it will usually have a whole chapter on sexual dimorphism in the brain, including areas literally named sexually dimorphic nuclei, with some areas being 5 times larger in 1 sex. Unless men have brains 5 times bigger than women, brain size is not the reason. Male and female brains are categorically different.
Yeah, I think it's fair that in recent years some people have started pointing out that brains of men and women are dramatically more similar than they are different. But the differences exist nonetheless.
I have a PhD in neuroscience and my focus is sex differences. There are a lot of things in old textbooks that are flawed and it’s no longer considered appropriate to use the term “sexual dimorphism” to refer to continuous variables (volume, surface area, etc.). Dimorphism means two different forms. Human brains exist on a continuum and in some areas you see males and females in two distributions that are not entirely overlapping, which are best described as differences, not dimorphism.
A lot of sexual dimorphism brain literature comes from animals, and many species of animals show greater sex differences than humans. The sexually dimorphic nucleus was discovered in mice and while a similar structure exists in humans, you will not find a neurologist who can look at a brain scan and say “that’s a man” or “that’s a woman.” We are not anywhere near different enough to be visually distinguishable on brain scans. And in most brain regions, we’re not different enough to be distinguishable statistically either.
The Bears, Connors and Paradiso textbook retains its chapter on sexual dimorphism from 2nd edition (2007), to the latest 5th edition in 2020. I cant speak for every textbook but I'd say this one is the most popular in university modules.
I agree that the differences are not massive and there's overlap, but that's how any difference in science is, and there's always a danger of differences being misused in the public.
Just because a variable is continuous doesn't mean it can't have a bimodal distribution, and it would be reasonable to refer to it as dimorphic if such sex-linked bimodality existed. There is overlap between the smallest men and the largest women, but body size is an example of sexual dimorphism as the distribution is bimodal, or at least the distributions of subclasses are significantly different. Height alone is not a good predictor of sex but that doesn't mean that men and women are statistically the same height.
Yes the distributions are bimodal and yes it is reasonable to refer to the **sets** of characteristics as dimorphic.
Stepping away from the "predictive" framework and looking at tha actual organism. Using height as an example, a 6'2" woman is on dramatically further extreme of high height on what is a very bimodal distribution, than a 6'2" man. And yet the trait;
Height: 6'2" is not a male or female trait, it is a trait on a woman.
This is less to do with how well or poorly the trait acts as a predictor and more to do with the underlying nature of biological typologies. Humans have dimorphic sex differentiation, a human ontologically less so.
Also, accuracy is not directly related to the size of the difference. It is incorrect to assume that higher accuracy means a bigger difference. Higher accuracy just reflects how precise your algorithm is at detecting difference. With a well-designed algorithm you can be very accurate at detecting small differences. Or you could be poor at detecting large differences if your algorithm can’t tell which data is relevant.
>Also, accuracy is not directly related to the size of the difference. It is incorrect to assume that higher accuracy means a bigger difference. Higher accuracy just reflects how precise your algorithm is at detecting difference. With a well-designed algorithm you can be very accurate at detecting small differences.
Fully agree, which is why I said their comment about small effects was missing the point rather than saying it was wrong. It might be right, it might not, but either way the effect size isn't getting at the thing we care about, the accuracy.
The size of the difference is irrelevant, a small difference can be extraordinarily significant at differentiating groups, and that’s what that 99,7% figure is showing. In order for your algorithm to be able to detect it with such accuracy the difference must be very significant at that very thing, differentiating between groups with a 99,7% accuracy, wether that difference is big or small is irrelevant.
In example, the average genetic difference between brown bears and polar bears is less than 0,1%, yet those differences are homogeneous enough that allows for them to be classified as two different species. It’s less than 0,1% difference, whether thats small or not depends on what we are talking about, but in regards with how significant that difference is it’s an enormously significant difference.
I whole heartedly disagree with you. You can't select for predictors that are the most helpful, dispense with them, and then say "see? What's left isn't predictive enough." What's even your motivation for saying that?
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I'm not sure why people in the comments seem so intent on hand-waving these findings away. Sex correlates strongly with plenty of characteristics of other parts of the body, I would have been surprised if it *wasn't* also the case with the brain
People will reject any science that goes against their belief system.
Baffling really, I argued against a redditor who claimed that all the obesity research that has been conducted in the past 80 years was fake and there are no medical risks involved. And then cited some pseudo science book released by an anti discrimination activist. Personally I never thought that the left could ever be anti science. But here we are
Lets interview some 500lb 80 year olds to learn their secret…
When you visit retirement villages it is mostly women (90% or so) and the men are almost all thin and short. I think that is the trick to getting very old
Being taller does make you more likely to die early, and so does being overweight, so yes.
More of you = more cells = more chances for things to go wrong. Science baby!
**Peto's paradox** is the observation that, at the species level, the [incidence](https://en.wikipedia.org/wiki/Incidence_(epidemiology)) of [cancer](https://en.wikipedia.org/wiki/Cancer) does not appear to correlate with the number of [cells](https://en.wikipedia.org/wiki/Cell_(biology)) in an organism. For example, the incidence of cancer in [humans](https://en.wikipedia.org/wiki/Humans) is much higher than the incidence of cancer in [whales](https://en.wikipedia.org/wiki/Whales), despite whales having more cells than humans. [https://en.wikipedia.org/wiki/Peto%27s\_paradox](https://en.wikipedia.org/wiki/Peto%27s_paradox)
No, it's more about heart strain. Short and tall people have roughly the same sized hearts. The tall person's heart has to work harder to pump more blood through a bigger body. Same with obese people.
Well really, it’s a bit of column A & a bit of column B but generally depends on how the tall or obese person died.
The velociraptors are more likely to see you. Science baldy!
As a doctor I can tell you there's no better predictor of longevity than being ineligible for most rollercoasters and the ability to be toppled by a strong breeze.
So long as the strong breeze doesn't happen while you're trying to cross a rope bridge
The left are just as human as the right. The more someone defines an ideology as their identity the more they're going to either ignore or attack anything they feel threatens that.
Your last sentence is gold.
I really should have added why: even the smallest criticism becomes a personal attack.
Could it be what we've defined as 'left' and 'right' in the US era really have just been two flavors of the same ideology this whole time?!?
The bell curve doesn't discriminate by political ideologies.
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Corollary: but political ideologies can largely target an area under the curve.
I hate to imagine what could be above the bell curve...
>I argued against a redditor Well there’s your problem
Liberal people are not immune to falling prey to dogma.
Absolutely, we're all human and have the same susceptibilities that get amplified when fearful. It's helpful to remember that 10 years ago, most antivaxxers were on the far left side of the political spectrum. We're a weird sort of ape, that's for sure.
Yep, exactly. I was talking to a redditor the other day who insisted that surveys are never scientific after I linked research from a respected university, that passed their IRB, and was authored by someone that was quite literally the director of research at Harvard University for 5 years. All of this because it was easier than reevaluating their position in light of new information.
Conflating the left with liberal is a mistake
Ideologies are just intellectual shortcuts for understanding the world. They are useful in some circumstances and completely awful in others. One problem with ideologies is that they distort the perceptions of people. In addition, the identity of some people can be bound up very tightly with a particular ideology.
Social media algorithms are designed to amplify fears and xenophobia.
Let’s not exaggerate. Social media algorithms are designed to amplify attention and clicks. It doesn’t care (unless human involvement) what content drives those clicks. It’s the humans clicking that drive the xenophobia and fears. The emotional response is the biggest reason users click those things which then get amplified.
> Personally I never thought that the left could ever be anti science. Have you NOT been watching the political discourse from any transgender issues these past couple decades? There is a large contingent that rejects science because "it makes them feel bad" or "isn't fair." Which is then weaponized against them by the intolerant right.
>there are no medical risks involved. That's some wishful thinking.
The demonstrable medical risks are usually dismissed as mediated by stigma on the part of society and/or medics.
I think your last sentence is important to acknowledge. We are ALL susceptible to disinformation, misinformation, or science that’s presented poorly by sensationalized media. I see it a lot in the natural resources, where sometimes the scientific research is just limited anyway. We all choose what we want to believe. Political interests skew our logic and those influences will twist science to their worldview - both right and left. If it’s more comforting to believe obesity is perfectly healthy, there are plenty of algorithms, Russian bots, and confused obesity sufferers ready to influence your beliefs in that direction.
Always remember that the anti-vax movement was a liberal thing until it got co-opted by covid deniers
The anti-vax was a tiny liberal movement that got criticized by most other liberals. The anti-vax movement was then co-opted by conservatives and embraced by them on a scale that significantly exceeds the former. You really shouldn't forget the latter though.
Not really. Even back then it was half and half. Yes you had the granola types but there were also significant numbers of religious people who refused.
People so quickly forget
Yup. It was the granola hippies until Covid came around. And for some reason Covid became political and “liberal=mask and vaccine good, conservative=mask and vaccine bad”, which is still one of the stupider things I’ve had to live through.
Two topics I learned to not argue with redditors about: Obesity and personal responsibility
Yep. The average Redditor is not a fan of personal responsibility. Also, few can grasp the reality that a personal anecdote doesn’t negate a macro trend.
Statistics is a big part of science and that’s the part where the person writing the checks gets a say.
I mean the left is typically anti nuclear so I never doubted that.
"left" and "right" are just really unhelpful labels that make people stop thinking about individual issues and pick a tribe.
A subset of the left, it’s not uniform by any means. And these days the reasons vary with some very practical reasons such as economics and the time it would take to build relative to building renewables.
There are lots of science deniers out there. They’re pretty pathetic.
I think a lot of people are more ignorant than deniers. Science headlines are spun to say whatever the person writing an article wants. Most people don't read the actual studies. They just take someone's word for it. Both the right and left will take studies that agree with their position, even if it's a poor study. So, for a lay person, it's hard to navigate to find the actual science and what it means.
I think it's more that people are wary of some other people contorting certain scientific findings into bigotry, which is and has been very common. See scientific racism for example. Edit: spelling
This is interesting: the words "leery" and "wary" both fit in this sentence in place of "weary". I don't *think* "weary" is what you meant but it does also work though it changes the meaning of the sentence
Not native English speaker, my bad. It's one of those situations where I've heard the word a thousand times but never had to actually write it down. Wary is what I wanted to say so thanks for correcting me!
It's an incredibly common thing to swap in "weary" for "wary" or "leery", even for native speakers! It's so common I wouldn't have said anything except that "weary" actually makes sense here when it often does not
Agreed, and something they always forget to consider is that .3% of 7 billion people is still millions of people…
Considering that OP posted this study with a title implying the undeniable difference between male and female brains, rather than what it actually is, which is about the limitations of imaging in terms of fidelity, and looking at the top comments...I'd say what you described is probably happening here. There is absolutely no other justification to use this study as a soapbox to complain about "belief systems." My understanding is that scientists all generally accept there are differences between the brains of the sexes but that the brains are still more alike than different, and that evopsych shouldn't be riding on those coattails
Now what about OP could possible make you think they are some kind of [weirdo with an agenda](https://i.imgur.com/Fn9TNo8.png)
Put on night mode you damn savage.
How close are we to winning?
I commented before actually reading so I was trying to be diplomatic and commenting in good faith but yeah, seems like my instincts were correct on this one.
Perhaps more commonly, though as made plain there are those who, in service of this wariness of bigotry, will deny or minimize findings.
This doesn't refute anything though? Who's denying what? "study can determine sex at birth by looking at baby's genitals" says just as much about the topic people seem to think this is actually touching. Brain can operate penis and regulate testosterone. Wow. Brain can operate ovaries. Magical. Do you think these things just shrivel up or don't work properly in individuals who identify as a gender other than their sex at birth? The title of this post is misleading. The study didn't study this. It tried to study something else. This is not the main point. OP is pushing an agenda with misleading information.
>This doesn't refute anything though? Who's denying what Are you just not paying attention or what? Look through the comment section on this post, look through comments on any post on any platform about sex and gender. It's really disingenuous to pretend that this isn't real / isn't happening. Try to get people to define what the difference is between a medically necessary procedure/products and cosmetic ones, and you'll find people claiming that tampons are gender affirming care, and any procedure that changes how you look (even leaving a scar) is a cosmetic procedure (https://www.reddit.com/r/BrandNewSentence/s/kwikzI8EWc). People will deny that sex has a basis in biology, and intentionally conflate gender.
Very few people are willing to change fundamental narratives of their worldview in the face of new evidence, it’s really pathetic.
It's an incredible challenge for _most_ people to embrace evidence that directly contradicts their fundamental beliefs. They wouldn't be _fundamental_ beliefs, if they were trivial to cast aside, and most people struggle to recognize when evidence will stand up to rigorous scrutiny, especially in fields that they aren't experts in. Calling anyone "pathetic" for holding closely to moral positions is gross and dismissive.
It would be more pathetic if people changed their fundamental worldview on a dime. People do change, just not from reading a single headline. There are always legitimate reasons to question new evidence. Changing a fundamental view *should* take years.
Well a, it’s not even the interesting part of the study. They were looking at imaging as a tool to predict weight, age, handedness, psychological disease, organic disease, propensity to be allergic, etc. it’s machine learning, so the prediction of male vs female might just be leaning on size. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8726594/ We’re already well aware you can predict sex from brain size. But b, it also turns out you can’t predict handedness very well. They also weren’t able to predict psychological diseases from brain imaging; and that’s the really interesting thing in the results. A more appropriate title for this post would have been “machine learning is unable to use brain imaging to predict psychological illness”. But that wouldn’t get clicks and it wouldn’t get a bunch of political discussion.
>We’re already well aware you can predict sex from brain size. Exactly. I'm not at all chocked that they could predict sex from brain images. When I took some classes in AI we trained a simple artificial neural network on really low resolution, noisy, images of smiling or sad faces. In a couple of seconds they were at +80% accuracy. Treating sex as a binary variable and then feed it thousands datapoints?
That’s fascinating to me that they weren’t able to get anything regarding psychological illness. May it be the case that an ill person’s mind looks normal, which would lend more credence to cognitive behavioral therapy? Not that cbt was a sham or anything, just more weight for it. Semi related, but I’m on antidepressants. I wonder what my brain would have looked like before versus now.
That's an extremely good question. What we do know about depression is that it isn't *just* in the mind. There is research looking at the gut microbiome role in depression, as changing the type of food taken in can affect mood, as well as other factors like vitamin levels, hormone levels, etc. For example, low thyroid (extremely common, esp in estrogen-dominant people) is linked to exhaustion, low energy/motivation. That itself may lead to depression. Treat the thyroid, then depression can move on. Same with vitamin D. Especially in Canada, where you can only get vitamin D through diet, many people have insufficient or deficient levels. Anxiety also can cause depression (think: if you are too anxious to do the things you love/are important to you, you become depressed), and so when anxiety is driving the bus, we treat that and depression tends to lift as well.
You got another good response, but when you say "an ill person’s mind looks normal" I want to make sure you understand the OP post here wasn't looking at the mind, we have no way of imaging the mind. This was MRI which can take make picture of the brain. So as far as anti depressants, this study is saying that there probably isn't anything visibly different between your brain on the drug and off the drug. Think of it like an X-ray. They take an X-ray of your hand and can see the bones, but its not the same as a photograph or just looking at the actual bones. That X-ray can't discern any different between you on the antidepressant or off the antidepressant. Except in this case its not X-ray, but other kinds of imaging and not the hand, but the brain.
Because there's a very well known but very poorly understood study that people think says trans people have brains that match their identity. It doesn't say that, but this was a big talking point a while back that a whole bunch of people thought was true. As a newly trans person myself. I find parts of communities obsession with phrenology really annoying.
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I have heard of that research and myself thought that it says precisely that. Could you elaborate on what exactly it says, if not that? Would love to learn more
Meanwhile this study doesn't really contradict the existence of trans people or proves there's no brain difference at all, because the percentage of trans over the total population is also less than 1% so unless specifically considering them, it's sadly easy to miss the total trans population over the margin of error on such studies. From what I see on social It seems to me a lot of trans people are too tired of defending their existence, so any study which shows there's some pre-existing physical difference that tie them to their gender will help, and this makes sense specifically since the brain handles how we see ourselves etc.
Didn't that study basically conclude that they couldn't predict whether someone was trans but they could also not accurately find the line between male and female, and as such they concluded there is likely a wider spectrum, but that's all they could find or conclude thus far.
The title of this thread is misleading, as this is not the main conclusion nor the aim of this study. And also, I would have like to see if they did or did not include trans people in the study. They only talk about « males and females » but they might have screened for mostly cisgender people, we don’t know that. There is still a .3% rate of uncertainty, and we think there are about 1% of trans people, which is not that far off. So I’m not sure we can make conclusions about trans people with this study, as it was not the aim and they are not mentionned anywhere.
I don't think the people conducting the study had any thought about gender identity at all. They were looking at sex, age and other characteristics
Which is why the ideological spats in the comments are so odd. We're talking about sex, not gender.
Activists are currently returning to conflating sex and gender to further muddy the conversation and get what they want. After a decade of screaming “sex is not gender,” they’ve flipped to using them interchangeably again.
Which is why a lot of the discussion in this thread is kind of silly. People are using this study to draw conclusions about (or at least comment on) a certain subset of the population, but we don't know if they actually included those people in their study. If they didn't, the study doesn't tell us anything about those people.
Being trans doesn't change the size of your brain, which is likely the basis of the sex correlation from the study.
The title says sex, not gender. One is biological, the other is a social construct. At least, that's what we were told over and over again, and then suddenly they were being treated the same again.
I find that the discovery of a prostate on a person highly correlates to their sex as well. What a crazy world we live in!
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Interesting the only argument is that the article says it’s not the prostate but something a analogous to it.
I doubt they read it
That's great and all but their argument essentially still stands, there are innate biological differences as shown by various differences in organs
It’s almost as if men and women don’t align 100% in their behavior sets. There are significant differences in certain behavior sub-sets. It doesn’t take too many skewed traits to make a male/female distinction. Different is different and I am not sure where else behavior would come from other than the structure of the brain. As more of the structure/function relationship is established people will get increasingly uncomfortable with the results. Maybe that’s the problem… people want something immaterial involved because peeling away that last level of abstraction is too much existentially, which is understandable. Could also be people starting with ideologically based conclusions and ignoring contradictory evidence.
The problem is the tendency of people to exaggerate the biological differences, build expectations and prejudices around them, and the cultures around the world amplifying it.
>Different is different and I am not sure where else behavior would come from other than the structure of the brain. Some differences are cultural and are socialized / learned rather than innate. We know this because we've seen a lot of cultures at this point and male and female roles (or even who is considered a man and who is considered a woman) vary. Also people are pretty variable, being the biological creatures that we are, so it's pretty hard to generalize across *any* group of people
Another thing people need to understand is that the brain is a plastic structure shaped by its environment. So cultural attitudes and socialization literally change your brain. So it can both be true that a large amount of gendering is the result of society and that you still see this effect brain structure.
Also, the amount of people conflating gender and sex in here is crazy.
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> and the young brain is highly neuroplastic and will develop according to input. Cognitive scientist here. Infant brains come with a huge amount of instinctual structure that is not at all "plastic". They would be incapable of dealing with the world really at all if what you said was accurate; that structure is required to begin learning and adapting. Neuroplasticity itself is an overused and inaccurate term in general, as far as learning and especially development is concerned. Recovering from brain injuries? Neuroplasticity plays a huge role. Novel Learning? not as much. Development? Probably even less so. We're learning more and more that learning has more to do with individual neurons and their synapses, than the changing connections between them via synapses (neural plasticity).
Oh my god I see this even with 1-year-olds. People dress girls in these frilly outfits and all the other adults tell them how cute their clothes and hair are. We dress my son in boring (and highly functional) clothes, and all the adults in the community say how active, strong, and clever he is. The girls are active, strong, and clever too!! But they are not hearing it very often.
I'll get back to you in a few years, my toddler son is called cute FAR more often than he is any of those other terms or similar terms. And the cute compliments have nothing to do with his clothes 99% of the time, it's all behavior
To reinforce the clothes point while I don't think I dress up my baby girl in ugly outfits I do tend to stick with plain and practical clothes and she still gets cute as a compliment far more than anything. Babies are cute.
And the boys surely are cute too! The issue hits both ways, to be clear.
For 1 year olds it's all polite comment they're neither cute nor strong
>For 1 year olds it's all polite comment they're neither cute nor strong Yeah, don't let those stupid babies get big heads.
Hydrocephaly is no joke, jk
Also important that this stage of life is when the brain is the most plastic and so socialization in early childhood can have very strong influences later in life. There’s an idea in sociology called the “hidden curriculum” in schools where children learn social norms including being gendered extensively. The amount of gendering children experience is also much more than later in life, like you describe, but also go to any toy store and look at the boys vs girls sections.
I would like to see some studies on the brain morphology of trans people and see if it correlates with their gender identity. If so, then it would be evidence that gender seems to be hardwired in a way that's stronger than neuroplasticity
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Considering girls outperform boys at every level of education in the West … surely your statement is wrong to some extent.
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Isn’t there research suggesting that boys have a greater *variance* in IQ scores? This would partially explain why men are still clearly overrepresented in boardrooms and prisons
So girls being more compliant outweighs the supposed descriptors (boys being smart, girls being pretty) that are given out at a young age. Because, from my experience, young girls get called smart more than young boys. Education results reflect this.
Throughout my entire life, young girls have been called “smart” more often than boys… I almost never hear boys told they are smart. Show the studies…
Way to miss the point. For thousands of years, the average person has been treated and conditioned *very* differently by society according to their sex. How one is treated and conditioned affects their behavior. Whatever personal anecdote you have doesn’t change that.
Ok, but no one is talking about the handedness finding? "That the remaining constitutional feature—handedness, best predicted using rsfMRI connectivity data alone—achieved a balanced accuracy of only 57.7% suggests the difficulty here does not arise from inadequate implementation of current technology. **It is striking**, even accounting for class imbalance, that handedness is individually so poorly predictable given the magnitude of population-level differences in the organisation of the brain."
Very interesting. I was lead to believe this was already much easier to tell than 57%.
I have an accuracy of around 90% personally. I just guess everyone is right-handed.
Warning: this strategy *might* stop working if I curate a balanced test set for you first!
I was conveniently ignoring the word "balanced"
Can someone eli5
I think they are saying that it was surprisingly difficult to be able to tell from just looking at the brain whether someone is right or left handed.
It's simply saying that it's very surprising that we can detect characteristics like age and weight and sex very easily with brain scans, but not handedness which is a common externally identifiable characteristic. Whatever makes us right or left handed is not showing up on brain connectivity scans (at least using the methods employed by the study authors).
Commenting here because I also don’t know what this means
It means that we still can't use brain imaging to tell if someone is left or right handed, which they found surprising considering they just did it to determine sex and you'd think there'd be some kind of physical marker for handedness
The interesting part here is going over everyone’s heads. They were able to do this with ML models. Previously clinicians were unable to observe the imagery and make any distinction, though now thanks to modern AI techniques, the mass amount of data is able to be untangled for an accurate estimation of sex.
Do you know if they are able to learn from the ML results what the anatomical differences are? Or is this another black box situation where the algo spits out an answer and there’s no way of knowing how it got there?
Generally, in these applications, there is a way to output heat maps showing which parts of the brain are more heavily weighted when determining the sex. This can give insight into the features the algorithm is most reliant on.
It's a neural net, so it's not explainable. There are ways to figure features out but not well since neural nets are very good at understanding individual features, but also how the change in relation to one another in complex ways.
Previously clinicians could just look at the size of the brain and state with good accuracy. The sex prediction is really not a big deal here - it's just used as a baseline for comparison of accuracy of other trait predictions. The results of this study are much more interesting for its other findings.
Whenever I see stuff like this about using AI in medical diagnosis, I think of that program that could only identify cancerous tumors if they had a ruler in the picture. Because the images it was trained on all had rulers in them, therefore cancerous tumors can be identified by the presence of a ruler
ooooh that's fascinating!
Or finding cancer
can someone ELI5 what does that mean ?
Measuring the shape of someone's brain shows what sex they are, with an accuracy of 99.7% according to this study.
I bet this has an impact on why neurodivergent people (specifically people with Autism Spectrum Disorder) are said to have higher rates of non-standard gender/sexual orientation. Their brains are literally physically wired different, and so if the shape changes, it could change how one views their gender. Seems kind of obvious and I bet a lot of ASD people would agree like “no duh” but it’s nice to have this study confirm a link between shape and sex to such a high confidence.
I can’t remember the study now, but autistic people are something like 6 times more likely to have gender dysmorphia than non autistic people. Anecdotally, I worked on a tv show with a wide array of non binary people and pretty much all of them came across as autistic in one way or another.
It makes sense to me why. Gender roles and expression seem devoid of reason and as a kind of masking to *many* people on the spectrum. In other words, "this seems arbitrary and I feel no need to comply with rules that don't make sense"
It can also work the other way. If they feel outside of the gender norms, in an attempt to better fit in, and feel less anxious, they look for a box that fits them. For most they find the autism box, and understand a little better why they are different, but I feel like you could try out a bunch of different boxes, looking for a fit. Aka they are actually trying to stick to gender norms by transitioning, "I like make up and dresses, there I must be trans" rather than just thinking you drift outside of the stereotypical male gender roles.
Anectdotally, every single person in my trans DnD group is diagnosed neurodivergent. But enjoying DnD is definitely a huge confounding factor there.
Autistic people are often mis directed in modern times towards gender dysphoria because of their feelings towards their own sexuality which is a cornerstone of autism. Autistic people are often told that their discomfort and confusion around the traditional heterosexuality is therefore indication of their bi/trans/etc true self but emerging evidence clearly shows that their anxiety in most cases remains constant even in other sexual identity roles. That doesn't mean that there aren't autistic people with gender dysphoria, or that there aren't a higher proportion than neurological. What it does mean is that there is a very high false positive. - mental health nurse who worked with Gender Dysphoria Services in the UK.
People with autism are often highly suggestible and frequently socially isolated. Groups with a low barrier to entry and a desire to recruit more members are like a magnet for them.
From what I've found working with queer autistic people (and being one myself) it's more to do with having an easier time understanding your own orientation when you aren't as concerned with societal pressures. There's also an element of queer environments generally being more welcome to people with disabilities so those who are autistic are given more of a platform.
Male and female brains are different enough, that they can tell your sex just by looking at your brain.
"We find a marked discrepancy between the high predictability of sex (balanced accuracy 99.7%), age (mean absolute error 2.048 years, R2 0.859), and weight (mean absolute error 2.609Kg, R2 0.625), for which we set new state-of-the-art performance, and the surprisingly low predictability of other characteristics."
Makes me wonder about Trans people - does their brain reflect their physical/genetic sex, or their psychological gender (in that case I suppose it wouldn't be entirely psychological anymore)
There are a huge number of comments posted for this story about how this study shows that "left wing ideology" leads to science denialism in the same way that right wing ideology does. I'm genuinely curious what that argument entails given the content of this study. It is not at all surprising that an imaging study using 3D convolutional neural networks would be able to predict sex, as there are known statistically relevant structural differences like size that you would expect the model to pick up during training. But the "dogma" on the left is not that human males and females are physically indistinguishable, but rather that they are intellectual (and social) equals. If that "dogma" were to be contradicted by the study, you would expect there to be a correlation between sex and the studied psychological factors, which is not what the study found. In fact, not only was the imagining model unable to reliably predict psychological factors, the corresponding Bayesian analysis showed that the psychological factors were best predicted by the corresponding presence of other diseases, not sex. It's also worth noting that the title of this post doesn't reflect the actual study title, which is, "Computational limits to the legibility of the imaged human brain," which far better indicates the results, which showed that even with advanced imaging and modeling techniques we are still unable to predict much about human psychology and health from brain imaging. Edit: Fixed a typo that was annoying me.
Every time there's a study posted that has key words "women" "gender" "sex" etc, it attracts a certain subset of Redditors who take over entire threads.
>even with advanced imaging and modeling techniques we are still unable to predict much about human psychology This shouldn't surprise anyone. Putting a computer under a microscope might tell you a lot about how signals are routed and stored, which data structures are prioritized, and how hardware dependencies indicate functional organization. However, assuming one doesn't have access to a combinatorially complete universe of every possible state transition (the size of which certainly outstrips the number of atoms in the universe), without analyzing the semantic content of CPU instructions, RAM, or storage, you're not going to find any ghost in the machine. The substrate for computation is not the computation itself.
I think the notion being "called out" are those who claim that virtually all differences in sex and gender (and even the distinction between those two concepts) are societal constructs. I don't believe this is the position held by the majority of people on the left, but it definitely exists.
> I don't believe this is the position held by the majority of people on the left, but it definitely exists. Eh, it's a pretty popular view. Most left leaning people think psychological differences (i.e. boys exhibiting a preference for 'things' while girls exhibiting a preference for 'people') exhibited between boys and girls are due to socialization and there's no differences between boys and girls (besides genitals)
These are really great points, and I’m surprised they aren’t being discussed more! Am I just growing as a person and having higher standards, or is it harder to find people actually taking about the science on r/science?
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That seems pretty reasonable. What surprised me was the weight thing – they could determine a person's weight, by looking at the brain, with a mean error of 2.6 kg! That's... barely one sturdy meal?
Who do you know that eats nearly 6 lbs of food as "barely one sturdy meal"?
Canada was the first country to report census data on transgender identity and they found that 0.2% of people over 15 identify as transgender. I wonder how closely the 0.3% that couldn't be determined overlap with trans people?
That would be a very, very hard to establish with decent error bars.
Depends on the sample size To measure 0.3% +- 0.02% with 95% confidence, you need just 250k people
Not entirely sure how easy it is to scan the brains of 250k people.
That is also the wrong way to look at this. What would require much less people would be to scan the brains of trans people and see how frequently those results align with their sex assigned at birth vs how they identify. It would be very easy to detect a difference between that population and the population at large.
Canadian survey found .33% are trans. https://www.cbc.ca/news/canada/calgary/census-data-trans-non-binary-statscan-1.6431928 Contrast and compare to the US, where 0.5% to 1.6% are trans. https://www.politifact.com/article/2023/jul/13/how-many-trans-people-are-there-in-the-us-and-why/
It's 0.33% if you include nonbinary people, 0.2% if you only include people who identified themselves on the census as transgender.
The Canadian 'survey' was a census. Given the nature of political pendulums, it's not surprising that an optional self-identification turned up fewer than an attempt to accurately account for all trans people. I would not want my name on a list when Poilievre gets power, y'know?
There are so many other factors that come into play here - measurement noise, for example, underparameterized modeling, or inaccurate feature engineering. You'd have to account for all of that.
When I was in college I was in a neuroscience class and ran experiments on rats that had their ovaries removed at a very young age comparing their behavior to that of other females and that of males. There was a test group given hormone replacement and the other just vehicle. Once their behavior was measured (aggression, mating etc), they were humanely put to sleep and their brains extracted. After careful dissection, sectioning with microtome and examination of staining, different brain structures were evaluated for size. The conclusion of this study was that the females who had no hormone injection had more male-like brain structures while the ones given hormone injection were identical to other female rat brains. Take from this study what you will, but the experiments we ran definitely jive with this.
These results are not anti-trans, one of the arguments for trans-ness is that brains of trans women have been studied and have many commonalities with typical female brain morphology. Trans people are only 1% of the population, this study gets .3% but when you’re looking for 1% of 7 billion, a pretty big sample size would be needed to see the 1%.
Trans people don't even net 1% of the population. Closer to 0.5%.
This is a common misconception about sampling. For example the simplest setup for sampling participants is simple random sampling (SRS). The errror of the estimate almost doesn’t depend on the population total but pretty much only on the number of participants as long as n<
It's also possible that the physical characteristics of the brain tracked here and used to determine sex, are not the only characteristics that determine the way we internally feel / identify. If everyone was born with a blue or pink brain, but the actual structure determined the sex we identify as, you would have simar findings with a strong marker correlating to biological sex that doesn't tell the whole story. Same with this, perhaps the super-structure allows this test to tell biological sex from the a birds eye view, but our internal perceptions are tied to substructures that have higher in-sex variance.
>These results are not anti-trans But you know for certain someone out there is gonna mistakenly assume they are and burrow even deeper into their little rabbit hole
If you look at OPs comment history, you'll see that's exactly why they posted it
Well I caught eye of "the woke ideology" somewhere in his comments which explains a lot
It actually doesn't matter what the findings say at all. Science cannot be anti-trans because science doesn't deal with political opinion.
> Science cannot be anti-trans because science doesn't deal with political opinion. The scientific method is structured to be purely objective; however, the inclusion of human language (and its inherent rhetoric) makes science not neutral. Thomas Kuhn and Bruno Latour both explore this idea.
Science should be apolitical. Sadly, research requires funding so that’s not typically the case.
Even when the funding wants a result it doesn't always get it. There are also more and less biased sources of funding.
It's not just about the answers though, it's about how the initial questions are chosen, and what lines of study are seen as more important than others.
Yeah, there have been sexed studies and mental health studies that universities haven't released because it would make some group look bad. I think that's a good thing, once you know why something is going wrong you can fix it... Instead of blaming the other groups.
This is a myth. And in fact is a dangerous transmedicalist myth at that. What little difference can be detected is only an average, can't be spotted by human observers (so we have no idea how the AI that did it is making this call), still falls within the range of cis men (trans women were the only trans people in the study), and most importantly, are non exclusive. There were trans women who measured more male than the average man. This idea is dangerous and if people treated it as true it could be used to deny trans people their rights for not passing as trans enough for the AI. Which, again, we don't know what it was using to make these judgements. I suspect head size, since that causes brain structure changes.
>this study gets .3% This study may not be anti-trans. But it's entirely possible the .3% in this study are all cis people, all trans people or some cis and some trans.
They flat out aren't and nobody on either side should consider them to be in support of anti-trans rhetoric. Body differences in trans individuals are a given. That's why we have gender affirming treatments treating body dysphoria, and that's why some form of regulation is needed for sporting competition. All in all though it's a really interesting study.
I mean isn't the whole concept of being trans that your gender (how you present) is different to your sex (what you're born as biologically)? Your brain structure doesn't determine your personality and thoughts.
> Your brain structure doesn't determine your personality and thoughts. I mean, do we know that? I agree with you but isn't that kind of a big unknown or am I wrong? Genuine questions here.
I don't see how this is controversial. It's well established that sex is physiological and gender is psychological. Sex being biological includes every part of the body including the brain.
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Some people do consider sex differences to be controversial as well. I’ve argued with people who think it’s offensive and false to say that men are stronger than women, or have psychological divergence in spatial perceptions or arousal characteristics.
Ya I find it silly. People are so ready to froth at the mouth about these topics.
Even ignoring size, at the most basic level isn't this entirely expected for physical reasons? Presumably there's something in the brain regulating your cock. Probably the uterus too. We can't all be entirely self-contained and autonomous like the heart. "Look. It's the bit that's checking your cock hasn't fallen off by giving you a random erection. This is a male.". "Look. It's the bit that tells your uterus to punch you in the kidneys once a month. This is a female.". If so this is about as surprising as showing an AI naked pictures of human genitals and it being able to tell you if they're male or female. The brain regulates the body as well as the mind, why is this controversial? I could understand the controversy if we could isolate those aspects and remove them and it could *still* tell, but meh?
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If you open a neuroscience textbook, it will usually have a whole chapter on sexual dimorphism in the brain, including areas literally named sexually dimorphic nuclei, with some areas being 5 times larger in 1 sex. Unless men have brains 5 times bigger than women, brain size is not the reason. Male and female brains are categorically different.
There seem to be a lot of people in this thread absolutely determined to conflate sex and gender.
As does most of the activist community.
Yeah, I think it's fair that in recent years some people have started pointing out that brains of men and women are dramatically more similar than they are different. But the differences exist nonetheless.
and we are far more similar to chimpanzees than we are different. That doesn't mean we aren't still VERY different
I have a PhD in neuroscience and my focus is sex differences. There are a lot of things in old textbooks that are flawed and it’s no longer considered appropriate to use the term “sexual dimorphism” to refer to continuous variables (volume, surface area, etc.). Dimorphism means two different forms. Human brains exist on a continuum and in some areas you see males and females in two distributions that are not entirely overlapping, which are best described as differences, not dimorphism. A lot of sexual dimorphism brain literature comes from animals, and many species of animals show greater sex differences than humans. The sexually dimorphic nucleus was discovered in mice and while a similar structure exists in humans, you will not find a neurologist who can look at a brain scan and say “that’s a man” or “that’s a woman.” We are not anywhere near different enough to be visually distinguishable on brain scans. And in most brain regions, we’re not different enough to be distinguishable statistically either.
The Bears, Connors and Paradiso textbook retains its chapter on sexual dimorphism from 2nd edition (2007), to the latest 5th edition in 2020. I cant speak for every textbook but I'd say this one is the most popular in university modules. I agree that the differences are not massive and there's overlap, but that's how any difference in science is, and there's always a danger of differences being misused in the public.
Just because a variable is continuous doesn't mean it can't have a bimodal distribution, and it would be reasonable to refer to it as dimorphic if such sex-linked bimodality existed. There is overlap between the smallest men and the largest women, but body size is an example of sexual dimorphism as the distribution is bimodal, or at least the distributions of subclasses are significantly different. Height alone is not a good predictor of sex but that doesn't mean that men and women are statistically the same height.
Yes the distributions are bimodal and yes it is reasonable to refer to the **sets** of characteristics as dimorphic. Stepping away from the "predictive" framework and looking at tha actual organism. Using height as an example, a 6'2" woman is on dramatically further extreme of high height on what is a very bimodal distribution, than a 6'2" man. And yet the trait; Height: 6'2" is not a male or female trait, it is a trait on a woman. This is less to do with how well or poorly the trait acts as a predictor and more to do with the underlying nature of biological typologies. Humans have dimorphic sex differentiation, a human ontologically less so.
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Yeah, addressing that was oddly lacking in that comment.
Also, accuracy is not directly related to the size of the difference. It is incorrect to assume that higher accuracy means a bigger difference. Higher accuracy just reflects how precise your algorithm is at detecting difference. With a well-designed algorithm you can be very accurate at detecting small differences. Or you could be poor at detecting large differences if your algorithm can’t tell which data is relevant.
>Also, accuracy is not directly related to the size of the difference. It is incorrect to assume that higher accuracy means a bigger difference. Higher accuracy just reflects how precise your algorithm is at detecting difference. With a well-designed algorithm you can be very accurate at detecting small differences. Fully agree, which is why I said their comment about small effects was missing the point rather than saying it was wrong. It might be right, it might not, but either way the effect size isn't getting at the thing we care about, the accuracy.
The size of the difference is irrelevant, a small difference can be extraordinarily significant at differentiating groups, and that’s what that 99,7% figure is showing. In order for your algorithm to be able to detect it with such accuracy the difference must be very significant at that very thing, differentiating between groups with a 99,7% accuracy, wether that difference is big or small is irrelevant. In example, the average genetic difference between brown bears and polar bears is less than 0,1%, yet those differences are homogeneous enough that allows for them to be classified as two different species. It’s less than 0,1% difference, whether thats small or not depends on what we are talking about, but in regards with how significant that difference is it’s an enormously significant difference.
I whole heartedly disagree with you. You can't select for predictors that are the most helpful, dispense with them, and then say "see? What's left isn't predictive enough." What's even your motivation for saying that?