January 21, 2011

Under or over-estimating the influence of genes, depending on how hierarchical your society is

We ascribe so much of so many differences between people to environmental differences, and I'm not just talking about "don't go there" topics like whether someone is smart vs. dumb, where you have to say it's mostly environmental or suffer social shunning. One girl sees another girl with more lustrous hair than hers -- "I wonder what kind of product she uses?" One guy sees another guy with a man-boob chest -- "He must do a lot of bench pressing."

From what I've heard anecdotally, as well as what I've read about pre-state people's "folk biology," more primitive groups like hunter-gatherers are more likely to see the power of blood, heredity, or some transmissible inner essence -- whether or not they know what genes are.

Is this difference because primitive people live in fairly egalitarian societies, where the environment doesn't vary so much across people like it does in a more advanced society like ours? Their social hierarchy is a lot flatter than ours, and their diet is pretty similar across individuals because the easy stuff everybody picks (like nuts and berries) and the hard-to-get stuff like meat and organs winds up getting pretty evenly distributed among the group after a kill.

So if one girl has more voluminous hair than another, she probably has some genetic advantage whereby her body doesn't require as many resources to grow great big hair, or her genes make her more resistant to disease that would halt hair growth and rob it of its natural oils. It's probably not due to some difference in environment, like if she were eating a wholesome hunter-gatherer diet while the other girl was a nutrition-deprived vegan.

In a highly stratified society like ours, though, or any settled agrarian society, those are very real possibilities. This must be a decently large part behind the trend in more advanced societies toward down-playing the role of heredity and emphasizing the role of the environment. On some level, it's true: there is more environmental variance in an industrial society, so "nurture" probably plays a larger role in making people different. Not for all traits -- certainly not for ones where the advanced society has eliminated environmental variation in, for example, pathogen exposure by cleaning up the water and giving everyone shots early in life. But overall, it should go in that direction.

Hunter-gatherers are going to over-estimate the heritability of traits, and industrial people are going to under-estimate them. Still, it would be nice to survey a lot of them about a lot of traits and compare them to the actual estimates (taken from their own society), so we can see who's closer to the truth. My guess is the primitive people, since moderns are so completely clueless about so much of the world, being so divorced from our natural state. But it would be neat to see no matter who wins.


  1. Your gut feeling about conceptions of heritability, IMO, is likely to hold water, but I wonder whether nomadic herders' acquaintance with animal breeding (sans sedentism) might not foster even more 'essentialist' perspectives.

    Khalkh Mongols, e.g., commonly assert that the Chinese ancestry of exclusively Khalkh-speaking erliiz who were born and raised in Mongolia is -- apart from physiognomy -- necessarily evident in posture, gait, and a subtle Chinese mangling of pronunciation.

  2. In Geoffrey Miller's book Spent, he writes about how conspicuous consumption is a product of people living in low trust, diverse communities that have nothing bonding them together. People are forced to compete over who has the most expensive stuff for status.

    In more homogenous societies (not necessarily ethnically based, but based around some common theme), the people compete over other characteristics, making them feel much more a part of the neighborhood.


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