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Comment by philh | Hacker News Reader

> Human relationships are mostly defined by cultural norms, not genetics, or else short people would have been selected out millions of years ago.

I think that humans are taller than we were millions of years ago. So yes, in some sense short people are getting selected out. (Though I don't have data. I'm actually more confident that we're taller than we were thousands of years ago, than that we're taller we were pre-agriculture.)

2.5% of people will always be 2σ below the norm.

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Sure, and males are taller and stronger than women. But one doesn't have to be the strongest and the tallest. In fact if we observe the variation in today's population the minimum viable height and strength bar seems to be quite low, and since the distribution is approximately normal, it doesn't seem like evolution favors tall people more than short.

Curiously, sexual dimorphism may have something to do with our mating habits

  The sexes differ more in human beings than in monogamous mammals, 
  but much less than in extremely polygamous mammals.

http://en.wikipedia.org/wiki/Sexual_dimorphism

> In fact if we observe the variation in today's population the minimum viable height and strength bar seems to be quite low, and since the distribution is approximately normal, it doesn't seem like evolution favors tall people more than short.

I don't follow. If a trait is sexually advantageous, that doesn't mean the trait won't be normally distributed at any given time. It just means the trait will tend to increase with time. And I claim that this does in fact happen with height.

I also predict that if you did cross-cultural studies, you would find: in almost every culture, when people are free to choose their mates, taller males have more dating/marriage success, on average, than shorter males.

Of course you don't have to be the tallest and the strongest, but it helps.

Apparently height hasn't changed much since the dawn of man, but it has increased significantly (about 10cm!) in the past 150 years, due to better nutrition, but it's levelling off. It may thus be said that height is not seen as a genetic advantage in itself , but as a signal of better nutrition (although a few centuries is a short time for such a preference to be genetically selected for)

http://www.scientificamerican.com/article.cfm?id=why-are-we-...

That's interesting and surprising, thank you. I'm going to need to consider this further.

Humans are taller because of better nutrition, not due to genetics.

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