I haven’t read your book yet, so forgive me if you discuss this there. But I’ve been wondering:
Simple traits (such as an organism’s height) are probably relatively easy to alter via genetic mutations, without needing to combine many different genes chosen from huge populations. So, e.g., dog breeding altered dogs’ size relatively easily.
Complex adaptations aren’t nearly so easy to come by.
If intelligence is a conceptually simple thing, there might be simple mutations that create “more intelligence”—it might be possible to make smarter people/mice/etc. by tuning a setting on an adaptation we already have. (E.g., “make more brain cells”).
If intelligence is instead something that requires many information-theoretic bits to specify, e.g. because “intelligence” is a matter of fit between an organism’s biases and the details of its environment, it shouldn’t be easy to create much more intelligence from a single mutation. (Just as if the target was a long arbitrary string in binary, and the genetic code specified that string digit by digit, simple mutations would increase fit by at most one digit.)
From the manner in which modern human intelligence evolved, what’s your guess at how simple human (or animal) intelligence is?
You are even meaner than Shulman. We don’t know how human
intelligence evolved and we need to know it in order to answer your
question I think. This is where evolutionary psychology and differential
psychology (Am I using that term right?) must come together to
work this out.
We think that we know a little bit about how to raise intelligence. Just
turn down the suppression of early CNS growth. If you do that in one
way the eyeball grows too big and you are nearsighted, which is
highly correlated with intelligence. BRCA1 is another early CNS
growth suppressor, and we speculate in the book that a mildly broken
BRCA1 is an IQ booster even though it gives you cancer later. BTW
Greg tells me that there a high correlation between IQ and the risk
of brain cancer, perhaps because of the same mechanism.
But these ways of boosting IQ are Red Green engineering. (Red
Green is a popular North American comedy on television. The
hero is a do-it-yourselfer who does everything shoddily.)
On the other hand IQ seems to behave like a textbook quantitative
trait and it ought to respond rapidly to selection. We suggest that it
did among Ashkenazi Jews and probably Parsis. IQ does not seem
to have a downside in the general population, e.g. it is positively
correlated with physical attractiveness, health, lifespan, and so on.
Do we get insight into the costs of high IQ by looking at Ashkenazi
Jews? Do they have overall higher rates of mental quirks? Cancer?
I don’t know.
We think that we know a little bit about how to raise intelligence. Just turn down the suppression of early CNS growth. If you do that in one way the eyeball grows too big and you are nearsighted, which is highly correlated with intelligence.
There is now substantial evidence that there is a causal link between prolonged focusing on close objects—of which probably the most common case is reading books (it appears that monitors are not close enough to have a substantial effect) - and nearsightedness/myopia, though this is still somewhat controversial. This is the typical explanation for the correlation between myopia and IQ and academic achievement.
A genetic explanation is possible, and would be fascinating, but I wouldn’t want to accept that without further evidence. If the genetic explanation is true and environment makes no contribution, then I think one should find that IQ is more highly correlated with myopia than academic achievement—I don’t know if this has been found or not.
If the genetic explanation is true and environment makes no contribution, then I think one should find that IQ is more highly correlated with myopia than academic achievement
It’s like saying “if evolution is true, crocoducks should exist”. You are (deliberately?) misrepresenting opponent’s views. He meant that of all genetic variation affecting IQ, only small, but non-negligible, subset affects both myopia and IQ. However I still don’t quite get how larger brain can cause myopia rather than hyperopia.
Maybe the larger brain leads to more intelligence, and people with more intelligence read more, and reading more leads to myopia. (Whether reading actually leads to myopia can be questioned, but that doesn’t affect the point.)
I think one should find that IQ is more highly correlated with myopia than academic achievement
More correlated than academic achievement is correlated with IQ, or with myopia?
Your comment is a very good point. But IQ may be more-closely correlated with academic achievement than academic achievement is with reading books; so this comparison might not help. (And you want to talk about the variance in X accounted for by Y but not by Z, rather than place a bet on whether Y or Z has a higher correlation with X.)
Yes, of course. But remember that in science we are not in the business of “accepting” one thing of another. That is the domain of religion and politics. The only thing that matters is finding good hypotheses and testing them.
We think that we know a little bit about how to raise intelligence. Just turn down the suppression of early CNS growth. If you do that in one way the eyeball grows too big and you are nearsighted, which is highly correlated with intelligence.
That’s interesting. I found a 2006 paper which argued that a genetic mutation is responsible for myopia, and that it also increases intelligence, but the specific gene and mechanism involved were apparently still unknown at that time. Has there been some more recent research results on this topic?
Given the outward differences, it seems reasonable to expect to find fundamental differences in the portions of the genome that determine chimp and human brains—reasonable, at least, to a brainocentric neurobiologist like me. But as it turns out, the chimp brain and the human brain differ hardly at all in their genetic underpinnings. Indeed, a close look at the chimp genome reveals an important lesson in how genes and evolution work, and it suggests that chimps and humans are a lot more similar than even a neurobiologist might think.
...
… Still, chimps and humans have very different brains. So which are the brain-specific genes that have evolved in very different directions in the two species? It turns out that there are hardly any that fit that bill. This, too, makes a great deal of sense. Examine a neuron from a human brain under a microscope, then do the same with a neuron from the brain of a chimp, a rat, a frog, or a sea slug. The neurons all look the same: fibrous dendrites at one end, an axonal cable at the other. They all run on the same basic mechanism: channels and pumps that move sodium, potassium, and calcium around, triggering a wave of excitation called an action potential. They all have a similar complement of neurotransmitters: serotonin, dopamine, glutamate, and so on. They’re all the same basic building blocks.
The main difference is in the sheer number of neurons. The human brain has 100 million times the number of neurons a sea slug’s brain has. Where do those differences in quantity come from? At some point in their development, all embryos—whether human, chimp, rat, frog, or slug—must have a single first cell committed toward generating neurons. That cell divides and gives rise to 2 cells; those divide into 4, then 8, then 16. After a dozen rounds of cell division, you’ve got roughly enough neurons to run a slug. Go another 25 rounds or so and you’ve got a human brain. Stop a couple of rounds short of that and, at about one-third the size of a human brain, you’ve got one for a chimp. Vastly different outcomes, but relatively few genes regulate the number of rounds of cell division in the nervous system before calling a halt. And it’s precisely some of those genes, the ones involved in neural development, that appear on the list of differences between the chimp and human genomes.
That’s it; that’s the 2 percent solution. What’s shocking is the simplicity of it. Humans, to be human, don’t need to have evolved unique genes that code for entirely novel types of neurons or neurotransmitters, or a more complex hippocampus (with resulting improvements in memory), or a more complex frontal cortex (from which we gain the ability to postpone gratification). Instead, our braininess as a species arises from having humongous numbers of just a few types of off-the-rack neurons and from the exponentially greater number of interactions between them. The difference is sheer quantity: Qualitative distinctions emerge from large numbers. Genes may have something to do with that quantity, and thus with the complexity of the quality that emerges. Yet no gene or genome can ever tell us what sorts of qualities those will be. Remember that when you and the chimp are eyeball to eyeball, trying to make sense of why the other seems vaguely familiar.
If that’s actually correct, we should be able to just breed a superintelligence. Maybe not one as powerful as an AI gone foom, but still orders of magnitude higher than us mortals.
Unless he claims at some point that humans reached some sort of hard limit, but it seems vastly more likely that huge brains are costly and we’re the point where the tradeoffs balanced.
Supposedly human brain size is limited by the skulls that will fit out of our mothers, and human babies are actually born premature relative to other species because it’s only when we are premature that our skulls will still fit out.
And, since we’re born premature as you said, there’s already a partial workaround even if you need “natural” births for some reason (potential complications from the surgery?)
It must be simple in some way since it is so heritable. People with IQs of 90 and IQs of 140 both prosper and do fine. although there are lots of statistical differences between two such groups.
Other other hand if we take a trait like “propensity to learn language in childhood” this seems to me to be relatively invariable and fixed and so probably very complex.
Certainly one could breed for IQ and raise the population mean a lot. But what would we be doing to our children? People with 140 IQ seem to do all right but I would worry a lot about the kind of life a kid with an IQ of 220 would have.
Do you see any difficulties for very high IQ children other than isolation?
It’s a little much to expect people to have so much patience, but doing moderate IQ increases generation by generation, with large numbers of increased IQ children in each generation would do a lot to solve the social problems.
I haven’t read your book yet, so forgive me if you discuss this there. But I’ve been wondering:
Simple traits (such as an organism’s height) are probably relatively easy to alter via genetic mutations, without needing to combine many different genes chosen from huge populations. So, e.g., dog breeding altered dogs’ size relatively easily.
Complex adaptations aren’t nearly so easy to come by.
If intelligence is a conceptually simple thing, there might be simple mutations that create “more intelligence”—it might be possible to make smarter people/mice/etc. by tuning a setting on an adaptation we already have. (E.g., “make more brain cells”).
If intelligence is instead something that requires many information-theoretic bits to specify, e.g. because “intelligence” is a matter of fit between an organism’s biases and the details of its environment, it shouldn’t be easy to create much more intelligence from a single mutation. (Just as if the target was a long arbitrary string in binary, and the genetic code specified that string digit by digit, simple mutations would increase fit by at most one digit.)
From the manner in which modern human intelligence evolved, what’s your guess at how simple human (or animal) intelligence is?
You are even meaner than Shulman. We don’t know how human intelligence evolved and we need to know it in order to answer your question I think. This is where evolutionary psychology and differential psychology (Am I using that term right?) must come together to work this out.
We think that we know a little bit about how to raise intelligence. Just turn down the suppression of early CNS growth. If you do that in one way the eyeball grows too big and you are nearsighted, which is highly correlated with intelligence. BRCA1 is another early CNS growth suppressor, and we speculate in the book that a mildly broken BRCA1 is an IQ booster even though it gives you cancer later. BTW Greg tells me that there a high correlation between IQ and the risk of brain cancer, perhaps because of the same mechanism.
But these ways of boosting IQ are Red Green engineering. (Red Green is a popular North American comedy on television. The hero is a do-it-yourselfer who does everything shoddily.)
On the other hand IQ seems to behave like a textbook quantitative trait and it ought to respond rapidly to selection. We suggest that it did among Ashkenazi Jews and probably Parsis. IQ does not seem to have a downside in the general population, e.g. it is positively correlated with physical attractiveness, health, lifespan, and so on. Do we get insight into the costs of high IQ by looking at Ashkenazi Jews? Do they have overall higher rates of mental quirks? Cancer? I don’t know.
HCH
They’re engaged. :)
There is now substantial evidence that there is a causal link between prolonged focusing on close objects—of which probably the most common case is reading books (it appears that monitors are not close enough to have a substantial effect) - and nearsightedness/myopia, though this is still somewhat controversial. This is the typical explanation for the correlation between myopia and IQ and academic achievement.
A genetic explanation is possible, and would be fascinating, but I wouldn’t want to accept that without further evidence. If the genetic explanation is true and environment makes no contribution, then I think one should find that IQ is more highly correlated with myopia than academic achievement—I don’t know if this has been found or not.
It’s like saying “if evolution is true, crocoducks should exist”. You are (deliberately?) misrepresenting opponent’s views. He meant that of all genetic variation affecting IQ, only small, but non-negligible, subset affects both myopia and IQ. However I still don’t quite get how larger brain can cause myopia rather than hyperopia.
Maybe the larger brain leads to more intelligence, and people with more intelligence read more, and reading more leads to myopia. (Whether reading actually leads to myopia can be questioned, but that doesn’t affect the point.)
More correlated than academic achievement is correlated with IQ, or with myopia?
Your comment is a very good point. But IQ may be more-closely correlated with academic achievement than academic achievement is with reading books; so this comparison might not help. (And you want to talk about the variance in X accounted for by Y but not by Z, rather than place a bet on whether Y or Z has a higher correlation with X.)
Yes, of course. But remember that in science we are not in the business of “accepting” one thing of another. That is the domain of religion and politics. The only thing that matters is finding good hypotheses and testing them.
HCH
That’s interesting. I found a 2006 paper which argued that a genetic mutation is responsible for myopia, and that it also increases intelligence, but the specific gene and mechanism involved were apparently still unknown at that time. Has there been some more recent research results on this topic?
There is apparently a research group in China that has some solid results but I have not seen them and do not know if they are out yet.
HCH
From The 2% Difference, an article by Robert Sapolsky:
If that’s actually correct, we should be able to just breed a superintelligence. Maybe not one as powerful as an AI gone foom, but still orders of magnitude higher than us mortals.
Unless he claims at some point that humans reached some sort of hard limit, but it seems vastly more likely that huge brains are costly and we’re the point where the tradeoffs balanced.
Supposedly human brain size is limited by the skulls that will fit out of our mothers, and human babies are actually born premature relative to other species because it’s only when we are premature that our skulls will still fit out.
Of course, we have cesarean births now, so...
Great points.
And, since we’re born premature as you said, there’s already a partial workaround even if you need “natural” births for some reason (potential complications from the surgery?)
That’s not really a new idea :P all those sci fi worlds with brain bugs and future humans worshiping the morlock king knew that.
It must be simple in some way since it is so heritable. People with IQs of 90 and IQs of 140 both prosper and do fine. although there are lots of statistical differences between two such groups.
Other other hand if we take a trait like “propensity to learn language in childhood” this seems to me to be relatively invariable and fixed and so probably very complex.
Certainly one could breed for IQ and raise the population mean a lot. But what would we be doing to our children? People with 140 IQ seem to do all right but I would worry a lot about the kind of life a kid with an IQ of 220 would have.
Do you see any difficulties for very high IQ children other than isolation?
It’s a little much to expect people to have so much patience, but doing moderate IQ increases generation by generation, with large numbers of increased IQ children in each generation would do a lot to solve the social problems.
an IQ 220 kid will do just fine in company of other IQ 220 kids and teachers.
Moved to the kibitzing thread.