Why are Europeans much taller than the rest of the world?

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Before people argue with the question assumptions—they are valid on a country-level comparison:

All of the countries with the tallest men are either in Europe, or majority-European settlers. Many majority-European nations have had a decrease in average height due to immigration over the last 50 years.

Nutrition is an obvious factor—African Americans are much taller on average than the people in most West African countries. There is significant admixture between European Americans and African Americans, but the difference is large enough that nutrition has to play a role. A more obvious example is North Koreans and South Koreans, who have large height differences, but have not been separate populations for long.

Nutrition however, does not explain everything. South Koreans are shorter than Europeans and they are not particularly malnourished.

Robinson et al (2015) found a correlation between the frequency of various genes, and average height, within Europe. The effect size was moderate (r=.51; p<.0001).

There could be a variety of reasons for this. Robinson et al found several genes corresponding to height, but did not say explicitly what type of quote ‘selection’ they believe is causing it.

A large driver of ethnic differences in human beings is sexual selection. Some of this is nature-driven, but a lot of it is cultural. Certain features are perceived as attractive, and then—whether or not those features actually are beneficial to survival—people with those features are much more likely to reproduce.

Some of the height variation across the planet is probably just some cultures perceiving height to be sexually attractive of one gender or another. If you notice, South Korean women are as tall as European women but South Korean and Japanese men are much shorter than European men. I can speculate that at some point, for a long period of time, height was viewed as attractive in women in South Korea, but not to the same extent in other parts of East Asia, and this speculation is not unreasonable.

Cultural sexual selection even happens outside of humans. At some point Peacock females started viewing males with longer feathers as more attractive, and over generations, Peacock males with long feathers reproduced more, and eventually Peacock males developed absurdly long feathers even though they are detrimental to their survival.

Another possible influence is Neanderthal admixture. European populations have some Neanderthal admixture, and East Asians have the highest. I happen to have 303 Neanderthal markers.

Most Europeans have over 300.

Two Neanderthal markers in particular RS7544462, and RS1877547 have been associated with increased height—I have neither.

I am not sure whether these two Neanderthal markers are more common in European populations or not, but maybe.

The reasons are probably all of the following:

1. Sexual selection (Europeans being more likely to reproduce if they are taller for arbitrary cultural reasons)
2. Natural selection (Europeans being more likely to survive to reproduce if they are taller in a harsh climate that generally does not require climbing trees)
3. Nutrition (less of a factor over time as more countries become rich)
4. Non-human admixture during the last Ice Age and perhaps earlier