That is good evidence that we aren’t in a mutation selection balance.
There are also game theoretic balances.
Here is a hypothesis that fits my limited knowledge of genetics, and is consistent with the data as I understand it and implies no huge designer baby gains. It’s a bit of a worst plausible case hypothesis.
But suppose we were in a mutation selection balance, and then there was an environmental distribution shift.
The surrounding nutrition and information environment has changed significantly between the environment of evolutionary adaptiveness, and today.
A large fraction of what was important in the ancestral world was probably quite emotion based. Eg calming down other tribe members. Winning friends and influencing people.
In the modern world, abstract logic and maths are somewhat more important than they were, although the emotional stuff still matters too.
Iq tests mostly test the more abstract logical stuff.
Now suppose that the optimum genes aren’t that different compared to ambient genetic variation. Say 3 standard deviations.
It’s just very hard for me to believe there aren’t huge gains possible from genetic engineering. It goes against everything we’ve seen from a millenia of animal breeding. It goes against the estimates we have for the fraction of variance that’s linear for all these highly polygenic traits. It goes against data we’ve seen from statisitcal outliers like Shawn Bradley, who shows up as a 4.6 standard deviation outlier in graphs of height:
Do I buy that things will get noisier around the tails, and that we might not be able to push very far outside the +5 SD mark or so? Sure. That seems unlikely, but plausible.
But the idea that you’re only going to be able to push traits by 2-3 standard deviations with gene editing before your predictor breaks down seems quite unlikely.
Maybe you’ve seen some evidence I haven’t in which case I would like to know why I should be more skeptical. But I haven’t seen such evidence so far.
I’m sort of confused by the image you posted? Von Neumann existed, and there are plenty of very smart people well beyond the “Nerdy programmer” range.
But I think I agree with your overall point about IQ being under stabilizing selection in the ancestral environment. If there was directional selection, it would need to have been weak or inconsistent; otherwise I’d expect the genetic low hanging fruit we see to have been exhausted already. Not in the sense of all current IQ-increasing alleles being selected to fixation, but in the sense of the tradeoffs becoming much more obvious than they appear to us currently. I can’t tell what the tradeoffs even were: apparently IQ isn’t associated with the average energy consumption of the brain? The limitation of birth canal width isn’t a good explanation either since IQ apparently also isn’t associated with head size at birth (and adult brain size only explains ~10% of the variance in IQ).
Yes. I expect extreme cases of human intelligence to come from a combination of fairly good genes, and a lot of environmental and developmental luck. Ie if you took 1000 clones of Von Neumann, you still probably wouldn’t get that lucky again. (Although it depends on the level of education too)
Some ideas about what the tradeoffs might be.
Emotional social getting on with people vs logic puzzle solving IQ.
Engineer parents are apparently more likely to have autistic children. This looks like a tradeoff to me. To many “high IQ” genes and you risk autism.
How many angels can dance on the head of a pin. In the modern world, we have complicated elaborate theoretical structures that are actually correct and useful. In the pre-modern world, the sort of mind that now obsesses about quantum mechanics would be obsessing about angels dancing on pinheads or other equally useless stuff.
Emotional social getting on with people vs logic puzzle solving IQ.
Not sure I buy this, since IQ is usually found to positively correlate with purported measures of “emotional intelligence” (at least when any sort of ability (e.g. recognizing emotions) is tested; the correlation seems to go away when the test is pure self reporting, as in a personality test). EDIT: the correlation even with ability-based measures seems to be less than I expected.
Also, smarter people seem (on average) better at managing interpersonal issues in my experience (anecdotal, I don’t have a reference). But maybe this isn’t what you mean by “emotional social getting on with people”.
There could have been a thing where being too far from the average caused interpersonal issues, but very few people would have been far from the average, so I wouldn’t expect this to have prevented selection if IQ helped on the margin.
Engineer parents are apparently more likely to have autistic children. This looks like a tradeoff to me. To many “high IQ” genes and you risk autism.
Seems somewhat plausible. I don’t think that specific example is good since engineers are stereotyped as aspies in the first place; I’d bet engineering selects for something else in addition to IQ that increases autism risk (systematizing quotient, or something). I have heard of there being a population level correlation between parental IQ and autism risk in the offspring, though I wonder how much this just routes through paternal age, which has a massive effect on autism risk.
This study found a relationship after controlling for paternal age (~30% risk increase when father’s IQ > 126), though the IQ test they used had a “technical comprehension” section, which seems unusual for an IQ test (?), and which seems to have driven most of the association.
How many angels can dance on the head of a pin. In the modern world, we have complicated elaborate theoretical structures that are actually correct and useful. In the pre-modern world, the sort of mind that now obsesses about quantum mechanics would be obsessing about angels dancing on pinheads or other equally useless stuff.
So I think there’s two possibilities here to keep distinct. (1) is that ability to think abstractly wasn’t very useful (and thus wasn’t selected for) in the ancestral environment. (2) Is that it was actively detrimental to fitness, at least above some point. E.g. because smarter people found more interesting things to do than reproduce, or because they cared about the quality of life of their offspring more than was fitness-optimal, or something (I think we do see both of these things today, but I’m not sure about in the past).
They aren’t mutually exclusive possibilities; in fact if (2) were true I’d expect (1) to probably be true also. (2) but not (1) seems unlikely since IQ being fitness-positive on the margin near the average would probably outweigh negative effects from high IQ outliers.
That is good evidence that we aren’t in a mutation selection balance.
There are also game theoretic balances.
Here is a hypothesis that fits my limited knowledge of genetics, and is consistent with the data as I understand it and implies no huge designer baby gains. It’s a bit of a worst plausible case hypothesis.
But suppose we were in a mutation selection balance, and then there was an environmental distribution shift.
The surrounding nutrition and information environment has changed significantly between the environment of evolutionary adaptiveness, and today.
A large fraction of what was important in the ancestral world was probably quite emotion based. Eg calming down other tribe members. Winning friends and influencing people.
In the modern world, abstract logic and maths are somewhat more important than they were, although the emotional stuff still matters too.
Iq tests mostly test the more abstract logical stuff.
Now suppose that the optimum genes aren’t that different compared to ambient genetic variation. Say 3 standard deviations.
It’s just very hard for me to believe there aren’t huge gains possible from genetic engineering. It goes against everything we’ve seen from a millenia of animal breeding. It goes against the estimates we have for the fraction of variance that’s linear for all these highly polygenic traits. It goes against data we’ve seen from statisitcal outliers like Shawn Bradley, who shows up as a 4.6 standard deviation outlier in graphs of height:
Do I buy that things will get noisier around the tails, and that we might not be able to push very far outside the +5 SD mark or so? Sure. That seems unlikely, but plausible.
But the idea that you’re only going to be able to push traits by 2-3 standard deviations with gene editing before your predictor breaks down seems quite unlikely.
Maybe you’ve seen some evidence I haven’t in which case I would like to know why I should be more skeptical. But I haven’t seen such evidence so far.
I’m sort of confused by the image you posted? Von Neumann existed, and there are plenty of very smart people well beyond the “Nerdy programmer” range.
But I think I agree with your overall point about IQ being under stabilizing selection in the ancestral environment. If there was directional selection, it would need to have been weak or inconsistent; otherwise I’d expect the genetic low hanging fruit we see to have been exhausted already. Not in the sense of all current IQ-increasing alleles being selected to fixation, but in the sense of the tradeoffs becoming much more obvious than they appear to us currently. I can’t tell what the tradeoffs even were: apparently IQ isn’t associated with the average energy consumption of the brain? The limitation of birth canal width isn’t a good explanation either since IQ apparently also isn’t associated with head size at birth (and adult brain size only explains ~10% of the variance in IQ).
Yes. I expect extreme cases of human intelligence to come from a combination of fairly good genes, and a lot of environmental and developmental luck. Ie if you took 1000 clones of Von Neumann, you still probably wouldn’t get that lucky again. (Although it depends on the level of education too)
Some ideas about what the tradeoffs might be.
Emotional social getting on with people vs logic puzzle solving IQ.
Engineer parents are apparently more likely to have autistic children. This looks like a tradeoff to me. To many “high IQ” genes and you risk autism.
How many angels can dance on the head of a pin. In the modern world, we have complicated elaborate theoretical structures that are actually correct and useful. In the pre-modern world, the sort of mind that now obsesses about quantum mechanics would be obsessing about angels dancing on pinheads or other equally useless stuff.
Not sure I buy this, since IQ is usually found to positively correlate with purported measures of “emotional intelligence” (at least when any sort of ability (e.g. recognizing emotions) is tested; the correlation seems to go away when the test is pure self reporting, as in a personality test). EDIT: the correlation even with ability-based measures seems to be less than I expected.
Also, smarter people seem (on average) better at managing interpersonal issues in my experience (anecdotal, I don’t have a reference). But maybe this isn’t what you mean by “emotional social getting on with people”.
There could have been a thing where being too far from the average caused interpersonal issues, but very few people would have been far from the average, so I wouldn’t expect this to have prevented selection if IQ helped on the margin.
Seems somewhat plausible. I don’t think that specific example is good since engineers are stereotyped as aspies in the first place; I’d bet engineering selects for something else in addition to IQ that increases autism risk (systematizing quotient, or something). I have heard of there being a population level correlation between parental IQ and autism risk in the offspring, though I wonder how much this just routes through paternal age, which has a massive effect on autism risk.
This study found a relationship after controlling for paternal age (~30% risk increase when father’s IQ > 126), though the IQ test they used had a “technical comprehension” section, which seems unusual for an IQ test (?), and which seems to have driven most of the association.
So I think there’s two possibilities here to keep distinct. (1) is that ability to think abstractly wasn’t very useful (and thus wasn’t selected for) in the ancestral environment. (2) Is that it was actively detrimental to fitness, at least above some point. E.g. because smarter people found more interesting things to do than reproduce, or because they cared about the quality of life of their offspring more than was fitness-optimal, or something (I think we do see both of these things today, but I’m not sure about in the past).
They aren’t mutually exclusive possibilities; in fact if (2) were true I’d expect (1) to probably be true also. (2) but not (1) seems unlikely since IQ being fitness-positive on the margin near the average would probably outweigh negative effects from high IQ outliers.