9 Comments

> Most farming/foraging societies put their kids to work at a fairly young age, when they are still small, and kids might even be a win, in terms of the ratio of calories produced to those consumed. Their caloric requirements at that age are also small, even when they are working hard.

I dunno; how would that work, exactly? I would expect kid labor to be less efficient than adult labor simply because kids need extra calories for growing, while adults aren't growing.

Expand full comment

The Status Syndrome: maybe low status is debilitating in itself.

Expand full comment

I know it's common sense that women most heavily have a bias against coupling with men who are short, much less shorter than themselves. This bias is evident across cultures. It's as biologically ingrained as caring about whether or not your future husband has a job (reverse the sexes and think about the fact that men don't care about these things, in general)

In cultures where women have less opportunity for economic mobility, one factor in declining height of the population is perhaps that height becomes less important vs. ability to acquire resources once the economy contracts.

These male birds have evolved do to crazy dances to attract mates since they have a lot of time on their hands living in an area where acquiring food is pretty easy.

http://www.youtube.com/watc...

But... what if it wasn't so easy. Priorities shift. Don't get me wrong, I'm sure the issue is more complex than this because height is also affected by nutritional issues.

Expand full comment

Regardless, wouldn't size be a signal of genetic quality - if you can survive well despite the handicap of being huge, that shows just how fit you are otherwise!

Expand full comment

I don't know about the tribe discussed here specifically, but the New Guinean farming-foraging cultures I read about 15 years ago, was more like suburban gardening in its physical requirements than historical agriculture as practiced in the Middle East and Medieval Europe, which was sheer backbreaking labor on the part of those actually practicing it. And only someone ignorant of agriculture would claim agriculture = agriculture; agriculture subsumes a huge variety of practices.

Expand full comment

Actually, the amount of physical labor and size required for agriculture is roughly proportional to ... the amount of physical labor and size required for agriculture! Most farming/foraging societies put their kids to work at a fairly young age, when they are still small, and kids might even be a win, in terms of the ratio of calories produced to those consumed. Their caloric requirements at that age are also small, even when they are working hard.

So I would say there might be genetics at work here, but perhaps operating in almost the opposite way -- a population that's been subsisting on foraging/farming for a long time might have effectively bred itself to respond to famine better (in long-term cognitive performance terms) than long-term herding/hunting societies, where the typical reaction to food shortage might have been for the tribes of bigger people to kill off or starve out the smaller ones. Size might be of no intrinsic advantage or disadvantage in food-getting generally, but it certainly is an advantage in fighting.

It might be interesting to compare with Japan. Kiichi Miyazawa was by far the most the most intelligent Prime Minister Japan has had in the last few decades, but he was also its shortest. I live in Japan, and kids these days are starting to get pretty tall, but without getting noticeably brighter. Looks like it's kind of going the other way, if anything.

Expand full comment

Actually, this isn't that surprising. There is no reason for size or strength to be strongly selected for in a hunter-gatherer culture; greater size and strength became an advantage only with the grueling labor of agricultural societies; in the respect of labor, farming-foraging societies are closer to hunter-gatherer economics than fully agricultural ones.

Expand full comment

This result helps clear our thinking.

A theory of why height is positively correlated with IQ, income, etc..., should take into account why this is not true in a rural agrarian culture.

My guess would be it has something to do with entrepreneurialism, as there is less room for that in the "foraging-farming society".

Expand full comment

Strange. Even if the Tsimane live in an evolutionary equilibrium where the benefits of greater than average height are offset by its greater energy requirements, you would still expect to see effects in some of those outcomes.

Expand full comment