Warning: This post might be depressing to read for everyone except trans women. Gender identity and suicide is discussed. This is all highly speculative. I know near-zero about biology, chemistry, or physiology. I do not recommend anyone take hormones to try to increase their intelligence; mood & identity are more important. I am myself a fairly high-T dude.

Why are trans women so intellectually successful? They seem to be overrepresented 5-100x in eg cybersecurity twitter, mathy AI alignment, non-scam crypto twitter, math PhD programs, etc.

To explain this, let's first ask: Why aren't males way smarter than females on average? Males have ~13% higher cortical neuron density and 11% heavier brains (implying   more area?). One might expect males to have mean IQ far above females then, but instead the means and medians are similar:

Left. Right.

My theory is that too much testosterone makes you dumber, particularly during adolescence. You need a little for your cells & organs to work, but past a certain point it does more harm than good (for intelligence specifically —  motivation & happiness etc aside). Apparently this is not a new theory and people have posited a U-shaped curve for how testosterone affects IQ. The key (sad) claim is that the vast majority of men are on the too-much-T side of the curve.

Maybe trans women get the best of both worlds intellectually — a male skull with female chemistry.

How big is this effect? I will give anecdotal data. Of my six smartest male friends in high school, five had little-to-no interest in sex, and the sixth had an incredibly healthy body/metabolism (eg winning track & field). Three of them gender-transitioned since high school. I don't know the odds ratio but seems high. Consider also how few nerds have big muscles unless they do weightlifting or something. (Most moderately buff dudes do not have to try.) Apparently gifted schoolkids have low-T in studies as well.

Why is testosterone a nootropic then? I think the main harms of it come during puberty and early adolescence, or occur over many years. Also note that post-menopausal women seem to experience bigger benefits from taking estrogen & progestin.

Why didn't evolution give females big heads if it would make them all geniuses? Another anecdote. My sister has a big head. She was valedictorian in high school I think. She hit her head one day in middle school during gym class by running into a wall. She also fell off a bike and hit her head in high school. I have never hit my head and I think the main reason is that my arms are strong enough to catch myself. So maybe the big headed women would-be-ancestors fell and hit their heads.[1]

Why did evolution give most males so much testosterone instead of making low-T nerds? Obviously testosterone makes you horny and buff. But I think there is a second reason: you might kill yourself without it. Trans women have high suicide rates. Anecdotally, my smartest oldest brother had low sex-drive and small muscles and killed himself. Eliezer's brother killed himself [citation needed] and if he was like Eliezer then he probably had low-T. My low-T nerd friends seemed kinda suicidal sometimes.

Why don't cis women kill themselves then? Well they "attempt" it way more often but they somehow actually die 5x less often on net. Perhaps their testosterone/something-else is so low that they don't have the initiative/spontaneity/stupidity to actually do it. I think suicide is usually a very spur-of-the-moment thing and is misleadingly depicted as a never-ending battle situation in movies & books.

Do trans men get the worst of both worlds intellectually — female skulls and male chemistry? Yes.

First example had birth defect. Second example is trans woman.

Does testosterone just make you more interested & able to pursue non-intellectual things rather than make you literally straightforwardly dumber? I don't think so. There's only so many hours per day you can spend having sex. And IQ scores seem to show that the T makes you straightforwardly dumber. Furthermore, inclination to use your thinking muscles can be more important than the strength of your thinking muscles.

What about all the smart buff cis dudes? Hormones & skull are not the only factors.

What about all the smart cis women? Hormones & skull are not the only factors.

Society

Wherein I use my flimsy explanation above to give even flimsier explanations of the world. Confidence on each of these is like 40%.

Why is google so google? Like why is it so hard for anyone to like do anything there? Maybe by hiring exclusively by coding tests (low-T) they excluded most of the go-getters lets-do-an-actual-thing-right-nowers (high-T) and have no defense against middle management disease. (Seems the main contribution of the new guy on the Gemini team from Dwarkesh's podcast is to bring some high-T energy — I doubt he is much smarter than the people already there. Sounds like he was hired via side-channels as well.)

Why is nobody in San Francisco pretty? Hormones make you pretty but dumb (pretty faces don't usually pay rent in SF). Why is nobody in Los Angeles smart? Hormones make you pretty but dumb. (Sincere apologies to all residents of SF & LA.)

Why is the San Francisco government broken? The big tech employees lack initiative to fix it (low-T). The startup folks would rather start a startup. And once you have some money you can move to a better neighborhood.

Why are the sluttiest people usually pretty? High hormones make you prettier and sluttier.

Why are really good tech founders so rare? You have to have very high power-seeking/initiative (T) and very high IQ. This is an incredibly rare combination because the testosterone murders your IQ. You have to be a genius before puberty hits. Helps if your brain/head is giant. Look at eg Elon Musk & Jeff Bezos.

Why are trans women dominating internet intellectualities but not the tech biz world? Not enough initiative / power-seeking. There are exceptions.


Why did I write this if I don't think everyone should go start taking testosterone blockers because of it? If this explanation is correct and you invent a way to counteract the harm of testosterone on the brain then you could cheaply make ~all people a lot happier, hornier, hotter, more driven, and smarter without drawbacks. I have no idea if separating testosterone's benefits from its drawbacks is possible at all. The effect sizes seem big though.

If that's too hard, I suspect that some simple electrical stimulation in the womb could make infant females' skulls bigger and result in lots of genius women. If they don't fall off their bikes and hit their heads.

Edit April 26:

  • Added "(or just low-T)" to title.
  • Thought of some more potential evidence. The smartest cis women I've known almost all had lack of butt (women's most visible muscle -- so low testosterone?)
  • Nobody in the comments has presented any first-hand counter-evidence. Do you know lots of smart people in your muscly men groups or lots of big-butted brilliant women? Have you been to a city where people are both smart and beautiful? Are you in the trans men's science league? Are you a high-T man who experienced zero brain damage during puberty?  The opposite?  Share!
  • Can anyone who knows a damn thing about the relevant chemistry/biology comment on the plausibility of magic upside-only synthetic testosterone? That's where all the positive sum of this game is.

 Later that day: i asked my sister. She said all her smart friends (men and women) lack butts too! She and I both have the butt, so we are speaking against our own kind here.

  1. ^

    Then why didn't evolution give women big muscles? I think because if you are in the same strength range as men then you are much more plausibly murderable. It is hard for a male to say that he killed a female in self-defense in unarmed combat. No reason historically to conscript women into battle. Their weakness protects them. (Maybe someone else has a better explanation.)

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All the smart trans girls I know were also smart prior to HRT.

Yes my point is the low T did it before the transition

Did any of them have big muscles before the transition?

I always assumed that, since high IQ is correlated with high openness, the higher openness would be the cause of higher likelihood of becoming trans. 

(or, some more general situation where IQ is causing transness more than the other way around., e.g. high scores on IQ tests might be caused to some extent by earnestness/intensity etc., which could also cause more likelihood of becoming trans)

Then where are the smart trans men hiding?

I buy that trans women are smart but I doubt "testosterone makes you dumber" is the explanation, more likely some 3rd factor raises IQ and lowers testosterone.

Like what exactly? That seems unlikely to me. I suppose we will have results from the ongoing gender transitions soon.

I don't know enough about hormonal biology to guess a specific cause(some general factor of neoteny, perhaps??). It's much easier to infer that it's likely some third factor than to know exactly what third factor it is. I actually think most of the evidence in this very post supports the 3rd-factor position or is equivocal - testosterone acting as a nootropic is very weird if it makes you dumber, that men and women have equal IQs seems not to be true, the study cited to support a U-shaped relationship seems flimsy, that most of the ostensible damage occurs before adulthood seems in tension with your smarter friends transitioning after high school.

seems in tension with your smarter friends transitioning after high school.

They seemed low-T during high school though!

Yeah could be a third factor though. Maybe you are right.

The trans IQ connection is entirely explained by woman’s clothing being less itchy.

LOL! I don't think women's clothing is less itchy (my husband's isn't any itchier than mine), but even if it were, that advantage would be totally negated by most women having to wear a bra.

I think its more likely its the transgender - autism correlation....

 

  • some forms of autism come with higher iq (and other forms, really really  dont)
  • and there's the transgender autism correlation

which together would seem to predict transgender high iq people

(and also transgender low iq that you arent seeing due to ascertainment bias)

Why is nobody in San Francisco pretty? Hormones make you pretty but dumb (pretty faces don't usually pay rent in SF). Why is nobody in Los Angeles smart? Hormones make you pretty but dumb. (Sincere apologies to all residents of SF & LA.)

Some other possibilities:

  • Pretty people self-select towards interests and occupations that reward beauty. If you're pretty, you're more likely to be popular in high school, which interferes with the dedication necessary to become a great programmer.

  • A big reason people are prettier in LA is they put significant effort into their appearance -- hair, makeup, orthodontics, weight loss, etc.

Then why didn't evolution give women big muscles? I think because if you are in the same strength range as men then you are much more plausibly murderable. It is hard for a male to say that he killed a female in self-defense in unarmed combat. No reason historically to conscript women into battle. Their weakness protects them. (Maybe someone else has a better explanation.)

Perhaps hunter/gatherer tribes had gender-based specialization of labor. If men are handling the hunting and tribe defense which requires the big muscles, there's less need for women to pay the big-muscle metabolic cost.

The U-Shaped Curve study you linked does not seem to support really any solid conclusion about a T-vs-IQ relationship (in this quote, S men = "successful educational level", NS men = "unsuccessful educational level"):

  • In the total sample (S + NS men), the correlation between T to IQ was best described by a polynomial regression (3rd order), exhibiting an inverse U-shaped regression. 
  • In S-men, the relationship between T and IQ was best described by a polynomial regression equation of the 3rd order; however, the relationship was not U-shaped, but rather a positive correlation (low T: low IQ and high T high IQ). 
  • In NS-men, there was an inverse U-shaped correlation between T and IQ (low and very high T: low IQ and moderate T: high IQ)

So there are three totally different best regressions depending on which population you choose? Sounds fishy / likely to be noise to me.

And in the population that most represents readers of this blog (S men), the correlation was that more T = more IQ. 

I'm only reading the abstract here and can't see the actual plots or how many people were in each group. But idk, this doesn't seem very strong.

The other study you linked does say:

Interestingly, intellectual ability measured as IQ was negatively associated with salivary testosterone in both sexes. Similar results were found in our follow-up study showing significantly lower testosterone in gifted boys than controls (Ostatnikova et al. 2007).

which seems to support the idea. But it still doesn't really prove the causality - lots of things presumably influence intelligence, and I wouldn't be surprised if some of them influence T as well.

I only linked the U-shaped study to mention that someone had said something vaguely similar. Notice my words "people have posited a U-shaped curve...". Study indeed seems like garbage. Perhaps i should've said that explicitly.

But it still doesn't really prove the causality - lots of things presumably influence intelligence, and I wouldn't be surprised if some of them influence T as well.

Yes so the experiment is that a million people are starting up in taking hormones/blockers now. I don't think proper results are in but what I have myself observed seems like strong evidence that blocking T preserves or raises intelligence on the margin.

Alternative theory (which, to be clear, I dont actually believe, but offer for consideration)

  • Many of the high iq people are too autistic to be successful
  • but female hormones protects against the autism somehow, without impacting iq too much
  • so the successful high iq people tend to be trans more often on average 
[-]lc9d3-1

Why aren't males way smarter than females on average? Males have ~13% higher cortical neuron density and 11% heavier brains...

Men are smarter than women, by about 2-4 points on average. Men are also larger, and so need bigger brains to compensate for their size (though this does not explain the entire difference you cite).

I would have guessed high T is associated with lower neuroticism, but studies found weak or no effects afaict.

Someone on a subreddit said "free testosterone" is what matters and they usually just measure uh "regular testosterone" in blood or something. I have no idea if that's true. Know what those studies measured?

Wildly guessing here, but my intuition is that estrogen would have a greater impact on neuroticism than testosterone. Although I can't even say which direction.

I don't understand why you need to invoke testosterone. Transgender brain is special, for example, transgender women have immunity to visual illusions. Anecdotally, I have friends with gender identity problems who do not make gender transition because it's costly and they don't have it this hard, they are STEM-level smart and they are not susceptible to visual illusions. So, assuming that this phenomenon exists (I don't quite believe your twitter statistics), it's likely explainable by transwomen innate brain structure.

The other weirdness in your hypothesis is that puberty blockers is a quite recent therapy and it's not ubiquous - most intellectually accomplished transwomen are likely to have standard male puberty. Even low-T male have mindboggingly large amount of testosterone compared to female, which implies really weird dose-dependency between testosterone and IQ in puberty.

There are plenty of stupid and/or distracting behaviors testosterone can push you for without any kind of "chemical brain damage", not only sex. Testosterone is likely to make you seek social status and status-seeking is notoriously incompatible with intellectual pursuits. I don't know my testosterone levels, but I have plenty of concussions due to my tastes for physical activity and I consider myself pretty average, stereotypical male. I suspect that concussions is the first direct source of male brain deterioration and testosterone is related here because it induces risk-seeking. The second and third, I think, smoking and drinking, and non-surpisingly, it's another sort of typical risky teenage male activity.

transgender women have immunity to visual illusions

Can you source this claim? I've never heard it and GPT-4 says it has no scientific basis. Are you just referring to the mask and dancer thing that Scott covered?

Whoops, it's really looks like I imagined this claim to be backed more than by one SSC post. In my defense I say that this poll covered really existing thing like abnormal illusions processing in schizophrenics (see "Systematic review of visual illusions schizophrenia" Costa et al., 2023) and I think it's overall plausible.

My general objections stays the same: there is a bazillion sources on brain differences in transgender individuals, transgenderism is likely to be a brain anomaly, we don't need to invoke "testosterone damage" hypothesis.

There are plenty of stupid and/or distracting behaviors testosterone can push you for without any kind of "chemical brain damage", not only sex. Testosterone is likely to make you seek social status and status-seeking is notoriously incompatible with intellectual pursuits.

This is the strongest alternative explanation by far. I wonder what to look for to check this...

Copied from a reply on lukehmiles' short form:

The hypothesis I would immediately come up with is that less traditionally masculine AMAB people are inclined towards less physical pursuits.

If it is related to IQ, however, this is less plausible, although perhaps some sort of selection effect is happening here.

Your hypothesis is ignoring environmental factors. I'd recommend reading over the following paper: https://journals.sagepub.com/doi/10.1177/2332858416673617

A few highlights:

Evidence from the nationally representative Early Childhood Longitudinal Study–Kindergarten Class of 1998-1999 (hereafter, ECLS-K:1999) indicated that U.S. boys and girls began kindergarten with similar math proficiency, but disparities in achievement and confidence developed by Grade 3 (Fryer & Levitt, 2010; Ganley & Lubienski, 2016; Husain & Millimet, 2009; Penner & Paret, 2008; Robinson & Lubienski, 2011). [...]

A recent analysis of ECLS-K:1999 data revealed that, in addition to being the largest predictor of later math achievement, early math achievement predicts changes in mathematics confidence and interest during elementary and middle grades (Ganley & Lubienski, 2016). Hence, math achievement in elementary school appears to influence girls’ emerging views of mathematics and their mathematical abilities. This is important because, as Eccles and Wang (2016) found, mathematics ability self-concept helps explain the gender gap in STEM career choices. Examining early gendered patterns in math can shed new light on differences in young girls’ and boys’ school experiences that may shape their later choices and outcomes. [...]

An ECLS-K:1999 study found that teachers rated the math skills of girls lower than those of similarly behaving and performing boys (Robinson-Cimpian et al., 2014b). These results indicated that teachers rated girls on par with similarly achieving boys only if they perceived those girls as working harder and behaving better than those boys. This pattern of differential teacher ratings did not occur in reading or with other underserved groups (e.g., Black and Hispanic students) in math. Therefore, this phenomenon appears to be unique to girls and math. In a follow-up instrumental-variable analysis, teachers’ differential ratings of boys and girls appeared to account for a substantial portion of the growth in gender gaps in math achievement during elementary school (Robinson-Cimpian et al., 2014b).

In a lot of ways the way you are looking at the topic perpetuates a rather unhealthy assumption of underlying biological differences in competency that avoids consideration of contributing environmental privileges and harms.

You can't just hand wave aside the inherent privilege of presenting male during early childhood education in evaluating later STEM performance. Rather than seeing the performance gap of trans women over women presenting that way from birth as a result of a hormonal advantage, it may be that what you are actually ending up measuring is the performance gap resulting from the disadvantage placed upon women due to early education experiences being treated differently from the many trans women who had been presenting as boys during those grades. i.e. Perhaps all women could have been doing quite a lot better in STEM fields if the world treated them the way it treated boys during Kindergarten through early grades and what we need socially isn't hormone prescriptions but serious adjustments to presumptions around gender and biologically driven competencies.

performance gap of trans women over women

The post is about the performance gap of trans women over men, not women.

It implicitly does compare trans women to other women in talking about the performance similarity between men and women:

"Why aren't males way smarter than females on average? Males have ~13% higher cortical neuron density and 11% heavier brains (implying 1.112/3−1=7% more area?). One might expect males to have mean IQ far above females then, but instead the means and medians are similar"

So OP is saying "look, women and men are the same, but trans women are exceptional."

I'm saying that identifying the exceptionality of trans women ignores the environmental disadvantage other women experience, such that the earlier claims of unexceptionable performance of women (which as I quoted gets an explicit mention from a presumption of assumed likelihood of male competency based on what's effectively phrenology) are reflecting a disadvantaged sample vs trans women.

My point is that if you accounted for environmental factors the data would potentially show female exceptionality across the board and the key reason trans women end up being an outlier against both men and other women is because they are avoiding the early educational disadvantage other women experience.