22 Comments

Nice read! Glad someone had looked into this.

Expand full comment
Dec 29, 2022·edited Dec 29, 2022

Distribution of glacial ice masses could have been a cause of the Han IQ being higher than that of the Germanic nations. At the last glacial maximum, northern Europe was ice-bound, and the European peri-glacial tundra was at much lower latitudes than was the most northerly tundra in largely ice-free eastern Siberia, i.e., in the Upper Paleolithic Han populations probably had to function in colder climates than did Western Hunter Gatherer populations.

https://www.nature.com/articles/s41467-019-11601-2/figures/1

Expand full comment
Dec 28, 2022·edited Dec 28, 2022

The Templer p-values seem elevated to the extent that similar populations (for example, Baltic bordering and West African) are sampled via small, highly-divided political units that raise N, rather than by a biologically meaningful scheme that can be applied to all temperature regimes equally. Easy data is sloppy data.

Expand full comment
Jan 15·edited Jan 15

So there seems to be a Goldilocks zone for evolution of intelligence in humans? (pun intended).

Emil you are correct in surmising that there are countervailing factors. One fairly obvious one might be a sharp reduction in selection pressure within established agricultural communities - we know that adequate food produces a sharp reduction in mortality.

Then cultural or societal factors must be invoked. For example, the Greek city-states were notoriously combative and only became unified in the face of a greater threat.

And we know that culturally they valued intelligence - I refer to Odysseus.

Expand full comment

After becoming more intelligent wouldn't the groups start moving more south for an easier life?

Expand full comment

"But historically, it seems the most clever people lived in warmer climate, as judged by their ability to invent agriculture (Mesopotamia, India etc.) and, well, Western civilization (in Greece and Rome, not in Scandinavia!)."

Crop production means grain-based food, which makes larger populations possible. This in itself increases the occurrence of mutations that affect the intellect. However, mycotoxins in cereals, in particular aflatoxin (the most potent naturally occurring genotoxin), increase this effect by orders of magnitude due to extra mutations. It would be worthwhile to address this effect...

Expand full comment

I don't think the logic that suggests not migrating in winter should select for bigger brains is sound. Bigger rains aren't strictly better, they have an energy cost, to say cold climates favour big brains more than warm ones it needs to be the case that cold climates offer enough payoff for higher intelligence to offset the extra energy cost. Which isn't obviously true, maybe there's not actually anything you can use extra intelligence for and it's just a waste of energy. There's no reason to assume the point where the gains from extra intelligence balance the costs is higher in cold environments just because they're harsher.

Anyway, we'll be able to deduce IQ directly from the genome fairly soon, so we can just test archaeological remains and know for certain when intelligence increased for different populations. My hunch is we'll find it was within the last few centuries in most places, as is the case for the Ashkenazim.

Expand full comment

You can simulate changing temperature in hangar just with automatons which give more or less food/water.

Expand full comment
Dec 29, 2022·edited Dec 29, 2022

Is it possible to to test correlatoin IQ vs (summer temp minus winter temp)? or IQ vs. T1-T2*K and see which K gets best correlation.

The Australian Abos and Kalahari people are only recently live in deserts after their kin was displaced from more comfy environments, like you point what happened with Amerindians.

The fig 1 is probably more about nearly identical plant/insect species than only handful of specialists in entire world can tell apart of. For large mammals than humans domesticate, the picture would look somewhat different.

Expand full comment

Ashkenazi Jews were extremely small population in the middle ages, and still they developed high IQ.

Expand full comment