Uriah

In the published paper "East Asian" is left a little vague, but if you read the original preprint, go to p. 84 and zoom in close you can see all the populations. The selective signal is strongest in Koreans, Miao, Yi, Tujia, Han, Japanese, Hezhen, Naxi https://www.biorxiv.org/content/10.1101/146043v1.full.pdf …

Of note, SE Asians like Vietnamese and Thai lack the signal entirely, as do most Siberian groups not immediately adjacent to China. This helps to narrow down the ancient population where selection occurred: it was likely agricultural, but long before the first Chinese dynasties.

This is represents a serious challenge for all the previously imagined scenarios for how an environment could select for IQ. In such a primitive society it is difficult to imagine merchants or mandarins piling up wealth and babies Ashkenazi style.

On the other hand if this was somehow an adaptation to cold (Lynn's idea) why would most Siberians and all American Indians not show the elevated nonverbal IQs of the Han or Japanese?

The archaeological cultures (possibly Yanshao or the proto-Altaic Hongshan) that experienced this selection revolved around millet agriculture. If the selection revolved around unique cultural practices I'll never understand it, but if millet itself played a role that's a start.

In Yangshao something like 75% of the diet could derive from millet and this is interesting because Pearl Millet at least (the African variety), acts as a goitrogen, allowing for goitres to develop even when thyroid levels are normal.

The only scenario I have ever been able to imagine where IQ becomes higher among isolated farmers is as a reaction to widespread cretinism. 100 years ago Arthur Keith promoted the idea that parts of the East Asian skeletal for were pre-adapted to hypothyroidism