near-evolutionarily-optimal range. That has not happened with intelligence,
What makes you think this? As I said, it’s not clear to me that there’s been much selection pressure for intelligence in the past few thousand years.
Also, the “evolutionary optimum” can change. E.g. calories are not much of a problem in the developed world, but that’s recent.
Also, there’s always an influx of de novo mutations, and evolution has limited selection power. I’m not clear on the math here exactly, and I think kman has suggested that mutational load isn’t the main source of IQ-associated SNPs, but it demonstrates that it’s far from ironclad logic to infer from evolutionary pressure on a trait that the trait should be near optimum in linear variants. The brain is one of the organs with the most diverse gene expression profile (I mean, more genes are expressed in the brain than in most other tissues); and IIRC most genes are expressed in the brain (not confident of this, maybe it’s more like 1⁄3 or 1⁄2. But anyway, there’s a lot of genes potentially relevant to brain function, so there’s a lot of surface area for mutational load to drag things down a bit.
genes are not simply choosing a level of intelligence.
I don’t know what you mean by this. Are you talking about pleiotropy? Between what and what? I mean of course genes do lots of things, but IIUC so far as we’ve observed, the correlations between most measured traits are pretty small (and usually positive between traits most people would judge desirable, e.g. lower risk of mental illness and higher intelligence).
Downvoting because it seems like you’ve barely read anything I wrote and also don’t know anything about genetics or intelligence, and are now posting AI slop, but I will upvote a thoughtful post making an argument using information and logic that address why people think it might work.
What makes you think this? As I said, it’s not clear to me that there’s been much selection pressure for intelligence in the past few thousand years.
Also, the “evolutionary optimum” can change. E.g. calories are not much of a problem in the developed world, but that’s recent.
Also, there’s always an influx of de novo mutations, and evolution has limited selection power. I’m not clear on the math here exactly, and I think kman has suggested that mutational load isn’t the main source of IQ-associated SNPs, but it demonstrates that it’s far from ironclad logic to infer from evolutionary pressure on a trait that the trait should be near optimum in linear variants. The brain is one of the organs with the most diverse gene expression profile (I mean, more genes are expressed in the brain than in most other tissues); and IIRC most genes are expressed in the brain (not confident of this, maybe it’s more like 1⁄3 or 1⁄2. But anyway, there’s a lot of genes potentially relevant to brain function, so there’s a lot of surface area for mutational load to drag things down a bit.
I don’t know what you mean by this. Are you talking about pleiotropy? Between what and what? I mean of course genes do lots of things, but IIUC so far as we’ve observed, the correlations between most measured traits are pretty small (and usually positive between traits most people would judge desirable, e.g. lower risk of mental illness and higher intelligence).
Downvoting because it seems like you’ve barely read anything I wrote and also don’t know anything about genetics or intelligence, and are now posting AI slop, but I will upvote a thoughtful post making an argument using information and logic that address why people think it might work.