Comments on my previous post

One person linked evidence of a correlation between head size and intelligence. Two pointed to a biological cost that I had left out, the difficulty of getting a large head through the birth canal when giving birth. That made me think of an idea for a story I never wrote, about a species of marsupial. They knew that because of the difficulty of getting a large head through the birth canal, only marsupials that deliver their babies early and finish their babies in their pouches could develop intelligence. As they observe the Earth, they wonder where and why the intelligent marsupials responsible for skyscrapers and radio broadcasts are hiding.

There were three arguments in the comments that I think are wrong. I heard each of them from multiple people.

One of these had to do with the nature of intelligence:

A key part of what our culture calls “smart” is the ability to manipulate abstractions, to remember complex structures of abstractions and data, and to embrace models of the world in imaginative ways. These are the things that mathematicians are good at.

The obvious answer to your question, which any socially conscious high school student could tell you, is that academic intelligence is not correlated with social consciousness.

Nerds often lack basic social awareness. Cool men and women have more sex and therefore more children.

Being smart enough to understand and develop theoretical physics won’t help you one bit in beating that woolly mammoth. For most of human history, we’ve needed street smarts and practical skills.

This interpretation of my post may be partly due to my use of “genius” in the title, which to many people denotes some form of intelligence, mathematical ability rather than the ability to run a business or manipulate people. That was not my intention. Elon Musk is a genius. Barack Obama is very smart. I suspect that basketball stars are very intelligent, although I have no data — they perform very complex physical and tactical calculations in real time. It takes brains to be a successful con artist, probably to succeed, even survive, as a mafia captain.

Another argument:

I personally know a very ugly and not so smart woman who has 6 children. She is a sweet person but…

…As long as such women can find men willing to mate with them, there is no “selection” for intelligence in evolution at all.

I have studied dozens of brilliant intellectuals. Perhaps a hundred. The pattern is clear that their intellectual pursuits are in most cases detrimental to their social and reproductive success.

I think you see a pretty strong correlation all over the world that the lower your intelligence, at least as long as you stay above the retardation, the more children you have. Prisons and welfare offices are full of people with ten children, ten different parents at 27. Where is your staff meeting of middle class HR people, not so much. Trailer parks and ghettos are full of children, upper middle class apartment complexes, not so much.

We live in a society that is so wealthy that even a not so successful woman can afford to bear many children until they reach adulthood. We also live in a society with reliable contraception that allows people to sacrifice the purpose of their genes to their own purpose. Neither of these was true for most of our species’ history. So those observations, while they may be true, are not very informative in explaining the results of human evolution.

A third argument:

People achieve things as cooperative groups. It is very difficult to cooperate with people who are different from you. In general, I think people communicate well within 1 SD of intelligence. Above 2 SD they find it very difficult to understand.

Too Smart and You Go Crazy: Being very smart and living with regularity can be very difficult for some people; they often become sociopaths or strange recluses because of an overwhelming sense of loneliness or otherness. This is really bad for reproductive success in societies where being very smart doesn’t have the exponential rewards it does today.

Smart people often don’t adapt well: Similar to the above, but smart people often notice that what people are doing is stupid and refuse to play along, and pay the price. Some societies don’t have a high price for it, a smart person can become a priest or a shaman or something, but some will kill you.

If this is true, it implies that in a society with an average IQ of 100, an IQ of 150 might decrease reproductive success rather than increase it. But as long as an IQ of 115 increases reproductive success, intelligence is being selected for and should increase. When the average reaches 115, 130 should increase reproductive success, and so on. So while this is a reason why evolution might increase intelligence more slowly, it is not a reason why it should not increase it, nor is it an upper bound on how high it might eventually become.

A nice explanation for the question of why we are not all geniuses, which is due to environment rather than genes:

I would also add: fluoride, glyphosate, aspartame, glutamates, BPA/BPS, atrazine, chlorine, lead, GMOs, ethyl alcohol, full language, and the Common Core!

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