Testosterone and IQ

Almost twenty years ago I encountered the two-pronged IQ dilemma for the first time, when I realized that almost every second famous chess player was of Jewish descent. Around the same time I began to wonder why there are zero African mathematical or technological geniuses. This was genuinely troubling to me and in the first case I quickly accepted the reason brought forth by a book of chess history, that the systematic study of the Talmud uniquely prepared Jewish kids for playing high-level chess. I now know that this is at most superficially plausible as a closer look reveals that players like Gary Kasparov, Bobby Fischer or Levon Aronian likely never even set a foot in a synagogue.

My cope for the absence of African genius in technical areas was more ingenious and anticipated this blog to a certain degree. I had read about the Eysenck-study which is still a favorite of newspapers to trot out whenever the need arises. The Eysenck study was published in several steps so the numbers are different depending on which part one cites, but the way I remember the newspaper article, the kids of African-American GIs in Germany had an IQ of 99 for the boys and of 101 for the girls. I had also read that testosterone levels correlate negatively with IQ (for men). Despite almost two decades going by I still remember the claim, that this relationship was so robust that it was easily replicable with shoe size and math scores in a random class. Apparently there was an ideal testosterone level for mental achievements, which was in the low male range.

So I took these two disparate facts and combined them into the theory that higher testosterone levels in Africans raised the IQ of African women by bringing them closer to the low male level, but lowered the IQ of African men. The Eysenck-study was evidence in that direction, because the kids were only ten years old and only half African, so it was plausible that this bifurcation would show in full force after puberty. This fit perfectly with the evidence and the leftwing worldview I was raised in: The average IQ of all groups where the same, but patriarchy in Africa suppressed the expression of the superior mental abilities of African women.

Very happy with that theory I avoided checking any facts that might disabuse me off it. Of course the reality is that African women do not tend to do better in mathematics or IQ tests than African men. The testosterone-IQ-connection does not seem to have gained much traction either. However, it still strikes me as very plausible. Rarely are mathematicians or chess professionals particularly well muscled and rarely does it make sense to listen to what a physical athlete has to say. I was reminded of this again, when I saw the AlphaGo documentary recently released on youtube and listened to the unusually high voice of Lee Sedol.

That same high voice I had already noticed among top level chess players, for example, of the top of my head, Viswanathan Anand, Peter Leko, Veselin Topalov, Ivan Cheparinov and Anatoly Karpov. Now, there is such a thing as confirmation bias, so this list containing no less than three world champions does not constitute much evidence. But it would be an interesting project to quantitatively assess the pitch of the voice of top chess players compared to some baseline.

2 thoughts on “Testosterone and IQ

  1. That is an interesting question. It is possible that the association of IQ and testosterone might be following an inverted U-shaped graphic. The geniuses of 20th century don’t look like Kurt Russell but they don’t look like Micheal Cera either, as far as facial masculinity is concerned.


    1. Yeah, I read something along those lines. But there is always the possibility to consider that among healthy people IQ and testosterone levels are pretty straighforwardly anti-correlated, however below a certain level low testosterone in many cases points towards some underlying problems that also lower IQ. You’d have to look at tail effects to distinguish this case from a true U-shaped causal relationship.


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