AI Determines Sex of Person from Brain Scans
neurosciencenews.com
neurosciencenews.com
> Until recently, a model like the one Menon’s team employed would help researchers sort brains into different groups but wouldn’t provide information about how the sorting happened. Today, however, researchers have access to a tool called “explainable AI,” which can sift through vast amounts of data to explain how a model’s decisions are made.
> Using explainable AI, Menon and his team identified the brain networks that were most important to the model’s judgment of whether a brain scan came from a man or a woman. They found the model was most often looking to the default mode network, striatum, and the limbic network to make the call.
I don't know if I want to stake my legal rights on an MRI machine. Even if I have a "guy" brain I'd still rather stay on E.
Transition (and by extension gender) is something deeply personal that shouldn't be gated by physical characteristics, including brain development.
It's often associated with TERFs, but it is VERY common within transgender communities themselves. There's notion that certain gender identities are valid and others are not (especially being male/female), and there's also the notion that diagnosable medical issues are required to be truly transgender.
In this conversation, if you're AMAB, and have a male brain, and claim to have transitioned to being non-binary a gender essentialist might go "aha! Science proves they are nothing but a transtrender and a man" A constructionist would say "aha - the fact they have a male brain yet expresses a non-male gender identity proves they're a truly unique and special transgender person".
It seems like an easy way to be on the "Right side of history" to reject gender essentialism, since you end up never calling a transgender person invalid. There is a dark side to rejecting essentialism, which is if gender ISN'T essential, than logically it should be possible to change people's gender identity to a "better" one. Which can result in things like Joan/John https://en.wikipedia.org/wiki/David_Reimer.
Hope that helps!
That being the case, unless you changed it at a young age I'm not sure that this could be changed later on in life.
However, if we take a closer look, we see some important underlying issues.
In a famous study, the authors compared prepubertal and adolescent children, then suggest sex atypical cerebral differentiation occurs within these individuals [1].
The authors found sex atypical differences in the adolescent cohort, but the majority of that cohort is homosexual:
- Homosexuality = 23% of trans boys + 44% of trans girls (prepubertal cohort)
- Homosexuality = 100% of trans boys + 78% of trans girls (adolescent cohort)
The only non-sex typical finding which was specific to gender dysphoria was in visual network-1 (VN-1; via fMRI). It was suggested that alterations in this network may disrupt body perception in gender dysphoric individuals.
In another study by some of the same authors, they tested whether transgender people (with gender dysphoria) would have sex atypical hypothalamic activation to androstenedione, a steroid hormone in human sweat that causes sex-specific olfactory responses [2].
But similar to the previous study, sexual orientation was not accounted for. Why is this important? Well, the same sex atypical hypothalamic response is observed in homosexual men [3] and in homosexual women [4].
It's becoming increasingly clear that the only people with any sort of sex atypical cerebral differentiation occurs in homosexual individuals (on average).
This is further supported by functional connectivity studies of sex atypical amygdala co-variance. You can see this in Figure 1 of this paper: [5]. Notice the high similarity in amygdala activity (at rest) between heterosexual females and homosexual males (and vice versa).
Interestingly, in an effort to bring all of this together, this study examined the brains of heterosexual transgender people in order to control for sexual orientation: [6]. As Figure 1 of this paper shows, the authors found sexual dimorphism in various gray matter parameters in control male and females. However, these findings were not found in the heterosexual transgender population.
So rather than sex atypical brain structure/function, what is specific to gender dysphoria itself?
It's been shown that individuals with gender dysphoria show weaker structural and functional connectivity within the default mode network (DMN) of the brain, which is vital for body perception/image and self-referential processing [7]. Findings which have been replicated in [8] and [9].
The DMN consists of cerebral midline structures, including the medial prefrontal cortex (mPFC) and the posterior cingulate cortex (PCC). Interestingly, it's been shown that trans individuals (with GD) show a stronger activation pattern within these DMN structures when viewing pictures of their body morphed to the opposite sex: [10]. You can see the results in Figure 5 of this paper.
It's important to note that correlation is not causation. Just because we observe a different pattern in gender dysphoric subjects compared to neuro-typical controls, does not suggest it's innate (born with) or a product of post-natal experience. We simply do not know.
Also, transgender people tend to have lots of co-morbidities from depression, anxiety, anorexia, autism, and a homosexual orientation. All of this needs to be considered when looking at neuroscience studies on this population.
[1] Nota, N. M., Kreukels, B. P. C., den Heijer, M., Veltman, D. J., Cohen-Kettenis, P. T., Burke, S. M., & Bakker, J. (2017). Brain functional connectivity patterns in children and adolescents with gender dysphoria: Sex-atypical or not? https://pubmed.ncbi.nlm.nih.gov/28972892/
[2] Burke, S. M., Cohen-Kettenis, P. T., Veltman, D. J., Klink, D. T., & Bakker, J. (2014). Hypothalamic response to the chemo-signal androstadienone in gender dysphoric children and adolescents. https://pubmed.ncbi.nlm.nih.gov/24904525/
[3] Savic, I., Berglund, H., & Lindström, P. (2005). Brain response to putative pheromones in homosexual men. https://pubmed.ncbi.nlm.nih.gov/15883379/
[4] Berglund, H., Lindström, P., & Savic, I. (2006). Brain response to putative pheromones in lesbian women. https://pubmed.ncbi.nlm.nih.gov/16705035/
[5] Savic, I., & Lindström, P. (2008). PET and MRI show differences in cerebral asymmetry and functional connectivity between homo- and heterosexual subjects. https://pubmed.ncbi.nlm.nih.gov/18559854/
[6] Savic, I., & Arver, S. (2011). Sex dimorphism of the brain in male-to-female transsexuals. https://pubmed.ncbi.nlm.nih.gov/21467211/
[7] Burke, S. M., Manzouri, A. H., & Savic, I. (2017). Structural connections in the brain in relation to gender identity and sexual orientation. https://pubmed.ncbi.nlm.nih.gov/29263327/
[8] Uribe, C., Junque, C., Gómez-Gil, E., Abos, A., Mueller, S. C., & Guillamon, A. (2020). Brain network interactions in transgender individuals with gender incongruence. https://pubmed.ncbi.nlm.nih.gov/32057995/
[9] Feusner, J. D., Lidström, A., Moody, T. D., Dhejne, C., Bookheimer, S. Y., & Savic, I. (2017). Intrinsic network connectivity and own body perception in gender dysphoria. https://pubmed.ncbi.nlm.nih.gov/27444730/
[10] Majid, D. S. A., Burke, S. M., Manzouri, A., Moody, T. D., Dhejne, C., Feusner, J. D., & Savic, I. (2020). Neural Systems for Own-body Processing Align with Gender Identity Rather Than Birth-assigned Sex. https://pubmed.ncbi.nlm.nih.gov/31813993/
It doesn't, because there is no explanation for how it determines the difference. It's just as likely some confounding thing that's not causally based on the brain, like all these other "AI can tell" studies that don't identify an actual mechanism.
That said I'm surprised that we can't tell men and women apart from the brain. I would have assumed there would be some differences that would make it obvious at least for the average brain. It's more surprising to find they are indistinguishable.
You don't need to know the mechanism to prove that it "supports the theory that there is a difference in brain organization". If there wasn't a difference, it wouldn't be able to find it.
>It's just as likely some confounding thing that's not causally based on the brain
Given that it does it's identification by looking at the brain, whatever the cause is, it is ALSO manifested as a "difference in brain organization".
>That said I'm surprised that we can't tell men and women apart from the brain.
Who said we can't? The article points to that we can.
And there are other brain attributes besides organization we can use to tell them apart, the biggest being size, including size of certain structures.
I think the person you’re responding to is talking about confounding factors _outside_ the brain scan, like when a model that could identify skin cancer used the presence of a ruler as its most weighted input: https://venturebeat.com/business/when-ai-flags-the-ruler-not...
This is a huge problem in medical use for AI - you have non-technical medical professionals influencing the data used to train the model, and introducing biases in the data that the model is learning from.
Well, those are just "bugs" and the results are then useless.
My point is that results taking into account only the scan (not random correlations with outside factors), would indeed be able to prove differences between M&F brains, without needing to also give a mechanism for it.
1. There's an M/F letter or other identifying text on the scans 2. Men and women get put into the machine slightly differently, and the ai sees a slight difference in the pose of the scan 3. It sees something else that's identifying and pretty good at splitting, like ear holes for ear rings
Anyways, would recommend some caution, there’s no reason to believe there’s some obvious fundamental difference in brain organization that we can’t see ourselves, until the research is a bit further along :)
All the photos of tanks had clouds in the sky. And few to none of the counter examples had clouds. So darpa paid for an expensive cloud detector.
Without more information about the study, I'm guessing there's a 'M' or 'F' stamped on the image somewhere.
_edit_ Ah - https://gwern.net/tank the tank story
I don’t think an explanation is required for this.
I should be able to state that two species have a different lifespan based on a difference in mean age of death - without needing to provide any specific biological mechanism in my study.
Substitute that mean for a linear regression / neural network and the species lifespan for some vector of brain organisation to get the results in the article.
You need to control for confounders. For example, if I told you:
- Mean lifespan of species 1 is: 3 years - Mean lifespan of species 2 is: 10 years
Does that mean that species 2 has a longer lifespan than species 1?
What happens when you find out that species 1 is domesticated cattle, which has (almost) all of its males slaughtered at age 2?
You could then say "I meant for two species that are in controlled conditions", but now you need to define what conditions you're controlling, which implies what casual mechanisms you're controlling for.
Without thinking terribly deeply about it, it seems like this could be modified to "what correlated mechanisms we're controlling for", in which case, yes I think if we controlled for the highly correlated variable of "does this cow live on a meat farm" with the mean age, we would be able to make broad claims about cattle lifespan without needing to be privy to the internal mechanisms of the agriculture industry
> Until recently, a model like the one Menon’s team employed would help researchers sort brains into different groups but wouldn’t provide information about how the sorting happened. Today, however, researchers have access to a tool called “explainable AI,” which can sift through vast amounts of data to explain how a model’s decisions are made.
> Using explainable AI, Menon and his team identified the brain networks that were most important to the model’s judgment of whether a brain scan came from a man or a woman. They found the model was most often looking to the default mode network, striatum, and the limbic network to make the call.
What's more fascinating it that it's not just a parlor trick and actually can be "validated" in some sense by doing a cognition test for just that part of the brain and observing the differences. So the model said "check here and you'll see a difference," and apparently, they did.
> They developed sex-specific models of cognitive abilities: One model effectively predicted cognitive performance in men but not women, and another in women but not men. The findings indicate that functional brain characteristics varying between sexes have significant behavioral implications.
> “These models worked really well because we successfully separated brain patterns between sexes,” Menon said. “That tells me that overlooking sex differences in brain organization could lead us to miss key factors underlying neuropsychiatric disorders.”
Huh?
I’m not sure what you are saying here.
If there’s some subset of the pixels or whatever which the models predictions depend on more than the others, then, it depends on those more than it depends on the others.
Obviously it would be using the data it is given. That, doesn’t mean that looking into “what part of the data that it is given, is it using?” not meaningful.
Although never demonstrated, it's always been most intuitive to me that sex-related brain differences underlie gender dysphoria. I would feel exceptionally relieved and vindicated to finally have some objective, falsifiable observation to point at that suggests the reality of dysphoria.
Plus, there's a whole ton of confounding business we'll have to look out for. Just off the top of my head, you've got certainty intervals. And wouldn't it be prudent to at least examine the effects of various hormones like testosterone, dihydrotestosterone, estradiol, progesterone on the brain? Say, post age twenty five, pre age twenty five. And so on. Might exist, might not.
We're a long way from being able to have much certainty at all.
Brain structure, as in the gross features visible on imaging, would probably not dictate what kinds of hormones you body might expect. I think that sort of thing would occur at a much lower level, right on the receptors of the tissues, and would not be visible.
According to the article, we can.
How so? They are clearly saying they expected this to be possible already, until this article claimed otherwise (by suggesting AI is contributing something new here).
They are saying that this result will not resolve the disputes, because it doesn't address the core thing in dispute: that there are meaningful differences that people actually care about. For example, maybe it is possible to tell the sex based on the shape of the brain. This doesn't mean that men and woman think differently, which is what people are actually arguing about. And the AI in this study can't proof that, because it doesn't give us any further insights into how cognition works.
This point strikes me as actually pretty mundane and obviously correct. The fact that 5 people immediately seem to have misunderstood it (as in, they are not responding to the argument) seems to tell us something about their priors instead.
That's not their claim. Their claim is that there is some flaw ("confounding thing") in the study. They then go on to say that men and women's brains are "indistinguishable." Well, of course you will automatically assume there is a flaw if that is your belief.
On the other hand, welcome to the machine...
Sex is binary, based on gametes which are binary. Anything with a bimodal distribution will by necessity never be the right tool for determining something which is truly binary.
The next best determinant of sex other than gametes is the presence or absence of the SRY gene.
There is a kind of cocktail-party level expertise that is behind comments that scientific results are obvious. First of all, even if they were, it’s likely there’s a novel angle the researchers are targeting. We should ask ourselves why a researcher would spend time on such “obvious” results.
Conveniently, the article author asked the researchers why they would study this. It’s not just a question of whether their brains are dissimilar, but how.
Second, whether male and female brains are structurally similar is controversial. As the article states, brain structures tend to look mostly the same in men and women.
A hypothetical technology that could very accurately determine the sex of a brain would seem to be a boon for transgendered people. Early detection could mean better treatment and less suffering with fewer cases of desisting.
What is the specificity and sensitivity? Or hell just give me a confusion matrix. That'll give you the answers you care about.
If the sensitivity is extremely high then it's an excellent diagnostic for sexual characteristics that are a deviation from the norm. But otherwise tbh I just don't see it being a super useful test.
i.e. for people who ahead of time aren't known to be intersex or trans, it would be able to identify them with high accuracy.
And the sensitivity vs specificity will depend for each category they are testing for (i.e. testing cis male, cis female, trans masc, trans fem, nonbinary, and some of the different intersex categories).
i.e It could be a cheaper test to do than genetic testing and if particularly effective may be useful in identifying genetics associated with different sex characteristics.