Nested comments on Substack become unreadable after a certain number of levels, so I’m using this post to continue a conversation.

Jeff: We know that athletic ability is heritable in individuals, but you’d look pretty dumb if you said it’s plausible that Jamaicans are naturally better sprinters, Kenyans better distance runners, and African-Americans better basketball players.

Now if you said Kenyans are better distance runners and Norwegians better cross country skiiers, one could come up with a dumb but superficially plausible (because they look different, so they must be really different deep down) just-so story about different selective pressures in Norway vs Kenya.

And then I’d tell you it’s a dumb just-so story, and you could tell me that “explaining via heredity is plausible, but not proven. More research is needed to test the hypothesis.”

TGGP: I actually do think it’s likely that people of East African descent are naturally better long distance runners, while people of West African descent are naturally better sprinters.

That link doesn’t discuss it, but East Africans tend to be taller & thinner than West Africans, resulting in advantages in different sports.

Jeff: West Africans in general are not notably great sprinters. It’s specifically a few Caribbean islands that excel at it, and the best of them, Usain Bolt, is tall and thin. It’s not because Caribbeans have genes to be good sprinters. It’s because in Jamaica sprinting is pretty much the national sport and has been for decades.

Countries excel at whatever sport kids there are disproportionately into. Brazil, soccer. Japan, baseball. America, basketball. Norway, winter sports. And so on. With team sports, it’s obvious that it’s not genetic. With individual sports, if you’re prone to over-theorizing stuff, it’s easy to convince yourself that it’s genetic. But it’s really just how many kids went into the funnel and whether the talented among them got support.

TGGP: The West African advantage in sprinting isn’t just Jamaicans/Caribbeans. Look at this list of the top 25 men in the 100m:

There are 5 Jamaicans and 3 from Trinidad/Tobago. There are 10 Americans and 2 Canadians (recall that the Middle Passage mostly brought West Africans to the New World). The one remaining country with multiple people is Nigeria with 2. Aside from them, Namibia also has one entry, as does France and Portugal (again, of West African descent). Talking about the culture of the Caribbean can’t explain why Nigeria has more than the entire continent of Asia. Running fast for short distances is something basically all kids do all over the world, and no specific culture had to invent. The fact that continental West Africa has fewer entries per capita than the West African diaspora does indicate that some non-genetic factors probably play a role, but you can’t explain the odd coincidence of every entry being West African descended even though they live in multiple different regions/cultures.

Jeff: There are 3 million Jamaicans vs 44 million African-Americans, but Jamaica produces as many top 10 sprinters as the US and half as many top 25 sprinters as the US. Do you think all the fast slaves got sent to Jamaica or something?

TGGP: As I said, the per capita numbers indicate to me that there are some non-genetic factors. But the complete absence of any people not of West African ancestry (which is to say, the overwhelming majority of the Earth’s population) speaks much louder than 3 million vs 44 million having equal numbers in the top 10.

Jeff: It’s totally possible that West African genes help, but you have to add a bunch of epicycles to the theory to explain why West Africans make great sprinters in Jamaica, good sprinters in America, and are nothing special anywhere else. And if you just drop the West African bit and keep the epicycles, you have a more parsimonious theory with just as much explanatory power.


TGGP: I disagree, I think a theory about West African ancestry explains much more than your Jamaican/Carribbean specific theory. A simple version would be that there’s some threshold to be at all competitive at the top levels of the 100m, and only people with West African ancestry can reach that level. Right away you’ve explained the astonishing factoid that the vast majority of the Earth’s population which is NOT of West African descent is absent. Then afterward we can say that there are smaller factors which have effects on the margin. We place less weight on those factors because they explain less than the theory about West Africans. In your Jamaican/Carribbean theory, you ONLY explain those 8 out of 25. It’s an astonishing coincidence that the 17 non-Carribbeans in that group are also of West African descent. Even the two from Europe! Combine with that, we have what Greg Cochran noted: there are physical differences we know about which are quite relevant for sprinting! My bet is that the next time a non-Carribbean gets added to that list, they will also be of West African descent. How much would you wager against me?

Jeff: I wouldn’t wager much because the next guy will be African-American. But that’s mostly a function of US high school track demographics (plus America’s ridiculously good Olympic talent pipeline), not West African genes. If China wanted to churn out world-class sprinters like they do gymnasts and divers, it’d be a Chinese guy instead.

The nesting became too much after that last comment from Jeff, so I decided to move the discussion here.

TGGP: WHY are “US high school track demographics” such that people of West African descent dominate them? They’re a minority of the U.S population! Don’t you find it odd that both they and the Caribbean sprinters have that shared ancestry? Would you be willing to bet against me of whether the next person on the list who is NEITHER Caribbean nor American will also be of West African descent?