I think there is an argument that Harris is making serious errors, even if we ignore the historical and social context.
Default Hypothesis — whatever the factors are that influence individual differences in IQ, the same factors would influence average group differences.
This is of course true for any two arbitrary groups. The causal graph looks like this:
Environmental differences → IQ differences ← Genetic differences
If we had literally no information about the groups, our best hypothesis would be that both environment and genetics play a role. But this is not the case. It is obvious that there are many environmental differences between the groups, and we can safely assume that they have some effect on IQ differences. At this point the hypothesis that these environmental differences explain all of the IQ differences, and that we know nothing about the genetic differences, becomes very likely.
Considering that the variables are not binary, and that the extent to which environment should be able to affect IQ is not known with certainty, we can’t deduce that the expected genetic differences are zero, but the expectation should shrink dramatically from the case where nothing is known (I admit, I don’t actually know how the math works out in the non-binary case).
Oh man, I really don’t want to be on the other side of that debate. But, I swore allegiance to the cause of local validity, and I must uphold that.
Let’s use a simplified model: Total intergroup variance= P*(genetic component of variance) + (1-P)*(environmental component). This is very simplified because genes and environment interact, but it will suffice.
Your logic only works if our prior was: 50% that all the difference is environmental (P=0), 50% that all the difference is genetic (P=1). In this case, finding an environmental difference would disprove the existence of a genetic difference.
But that’s not what our prior is. The prior for biological group differences in a highly heritable trait is some bell curve of P, with its peak probably somewhere around P=0.5 (or at least neither P=0 nor P=1). The fact that IQ-affecting environmental differences exist only rules out P=1, which maybe changes the posterior expectation of P from 0.5 to 0.45, but not to 0.
After all, our prior was that we would almost certainly find environmental differences that affect IQ, so finding them can’t cause that much of an update.
And if we haven’t even proven that the environmental differences affect IQ, only that they exist, then we shouldn’t update at all. Our prior for that was basically 1: any two groups will have some environmental difference (food, language, location...), so the existence of those differences can’t be evidence either way.
I don’t exactly know what you’re disagreeing with. I did not say that genetic difference is zero.
After all, our prior was that we would almost certainly find environmental differences that affect IQ, so finding them can’t cause that much of an update.
This is not a binary question as you seem to treat it. We need a probability distribution over “what difference in average IQ two groups in these two environments would have, if they were genetically identical”. And then depending on our beliefs about that, we could deduce that the genetic differences are a significant contributor, or that there is zero contribution, or even that “low-IQ” group has the superior genes.
And if we haven’t even proven that the environmental differences affect IQ, only that they exist
The kinds of environmental differences we’re talking about are things like poverty, discrimination, etc. I assume that their effect on IQ has been observed, at least for some of them.
Now, I don’t actually know what that distribution looks like. It could really be very insignificant. But if Harris does not make a good effort to evaluate this distribution and then update his P(“inferior genes”) accordingly, then he is making an error.
local validity
Somehow, whenever I see people link to that, I end up unimpressed.
All this discussion seems insufficiently specific to make actual progress.
Obviously there are imaginable states of affairs in which our best estimate of genetic differences should be very close to zero. (E.g.: Observed overall differences small, many environmental effects found and well understood, best estimate of total impact of all known environmental effects very close to observed overall difference.) Call this proposition “P0”.
Obviously there are imaginable states of affairs in which our best estimate of genetic differences should be rather large. (E.g.: Observed overall differences large, environmental effects looked for but few found to have any supporting evidence, best estimate of total impact of all known environmental effects much smaller than observed overall difference.) Call this proposition “P1”.
And obviously what we should think about this (if we think about it at all) depends a great deal on the details of the actual evidence: how big the various known effects are, how hard researchers have tried to make IQ (or whatever) be insensitive to many environmental factors, how much we trust any given bit of research not to be perturbed by the researchers’ prior prejudices, etc., etc., etc.
So far as I can tell, zulupineapple and Jacobian don’t disagree with any of that. I haven’t looked into the Harris/Klein affair much, but my guess is that they and the other people who have weighed in also don’t disagree with any of that.
But so much of the discussion—including pretty much everything above—seems to consist, modulo outright mistakes, of one person reiterating P0 and another reiterating P1. So, e.g., zulupineapple points out that there are known environmental factors (so far this is just P0) and then says “At this point the hypothesis that these environmental differences explain all of the IQ differences, and that we know nothing about the genetic differences, becomes very likely”. Well, no, at some point that happens but to know whether we’re at that point yet we’d need to know more about the environmental differences and more about the observations they’re meant to explain. And then Jacobian points out that we have some prior for what the relevant differences are and the effect of learning about environmental factors just shifts our probability distribution rather than ramming it all the way to 0. That’s more or less just P1. Then zulupineapple comes back, reaffirms that we should be adjusting probability distributions, and says that depending on our prior we might end up with an estimate of 0. That’s just P0 again.
Maybe Harris and Klein are also just reiterating P0 and P1, in which case what needs pointing out is that they need to engage with the details of the evidence. Maybe at least one of them is actually engaging with those details. But in either case, just repeating “P0! P1! P0! P1!” achieves nothing useful.
(I am not saying that anyone ought to be digging further into the evidence and trying to do better than P0 and P1. That might be a bad idea—one might e.g. decide that the chance of finding anything genuinely actionable is small, and that the most likely outcome is simply becoming a pariah to some fraction of the population for political reasons. But if it’s worth getting into this argument at all then I think what’s worth doing will have to involve getting more concrete than just P0 and P1.)
No, you’re missing the point. I have very little interest in whether P1 or P0 or some P2 is true (and I don’t really see Jacob strongly favoring one of those either).
Instead, my bold claim is that Harris is not actually evaluating the environmental effects. He says that he uses the “default hypothesis”, but that only makes sense if you have zero information about the environmental differences, which is not the case. Ignoring data you have to make some conclusions look more reasonable is an error.
Now, on the object level, I admit that I favor P0, because the idea of genetic differences doesn’t really make much sense to me. Why should they be there? Because only smart people managed to migrate out of Africa? Mabe by pure chance? Also, it seems to me that there are some hard-to-measure environmental factors, so it’s not surprising if the measured part of environmental contributions is small. But I actually know very little about this issue.
I think you have misunderstood at least one thing: P0 and P1 are definitely both true. (They are propositions of the form “there are imaginable states of affairs such that …”.)
Once again, I don’t know very exactly what Harris and Klein have said, so I can’t easily tell what if anything he’s doing with the environmental effects. Are you saying that he thinks there are none? (I am not a big fan of Harris, but I would be astonished if he were being that stupid.) If not, it’s not clear to me what specific “serious error” you think he is making.
Your original comment doesn’t help me here. It observes that there are environmental effects (which, again, surely Harris doesn’t deny) and then jumps straight to saying that “the hypothesis that these environmental differences explain all of the IQ differences, and that we know nothing about the genetic differences, becomes very likely”—and I don’t understand where that comes from. I mean, sure, it could well be true that the environmental differences explain everything. But it seems like you jump straight from “there are lots of environmental factors” to “environmental differences probably explain everything” and I just don’t see how you can do that without actually engaging with the details of the available evidence.
(Once again, I’m not saying that you should do that. Only that without doing that, I don’t see how you can reach the conclusion you say you do.)
Of course not, that would be too easy. He does, at some point, explicitly acknowledge that environmental effects exist and are “very important”. And then he proceeds to do nothing with those effects. If you admit that a factor is very important, but then arrive at the same conclusions as someone who believes that the factor has 0 effect, that is still a problem.
I imagine the thinking goes like this. He observes that there are relevant factors X, Y, Z. He notices that Z has a lot of uncertainty, or is hard to work with, or ect. Then he decides that he will look at X and Y in isolation. And then he assumes that whatever conclusions X, Y have lead him to, actually have some bearing on the real world. Depending on Z this may or may not be the case. If it happens that Z really is 0, then you arrive at the correct conclusion, but even then, the path you took to get there is still wrong.
Of course, all of this is very hard to talk about when nobody gives their actual probability estimates (and giving probability estimates is also very hard). In particular this is because the value of P(“inferior genes”) doesn’t seem central to Harris. There is a good chance that I’m misreading him and that his estimate of P(“inferior genes”) is not as high as I assume it to be, and that he really is honestly updating on the environmental differences.
Still, the claim that Harris is making an error seems more likely to me. At least now you better understand what error I’m accusing him of? (By the way, I’m also accusing him of the error pointed out by RamblinDash, but didn’t want to duplicate it).
I think there is an argument that Harris is making serious errors, even if we ignore the historical and social context.
This is of course true for any two arbitrary groups. The causal graph looks like this:
If we had literally no information about the groups, our best hypothesis would be that both environment and genetics play a role. But this is not the case. It is obvious that there are many environmental differences between the groups, and we can safely assume that they have some effect on IQ differences. At this point the hypothesis that these environmental differences explain all of the IQ differences, and that we know nothing about the genetic differences, becomes very likely.
Considering that the variables are not binary, and that the extent to which environment should be able to affect IQ is not known with certainty, we can’t deduce that the expected genetic differences are zero, but the expectation should shrink dramatically from the case where nothing is known (I admit, I don’t actually know how the math works out in the non-binary case).
Oh man, I really don’t want to be on the other side of that debate. But, I swore allegiance to the cause of local validity, and I must uphold that.
Let’s use a simplified model: Total intergroup variance= P*(genetic component of variance) + (1-P)*(environmental component). This is very simplified because genes and environment interact, but it will suffice.
Your logic only works if our prior was: 50% that all the difference is environmental (P=0), 50% that all the difference is genetic (P=1). In this case, finding an environmental difference would disprove the existence of a genetic difference.
But that’s not what our prior is. The prior for biological group differences in a highly heritable trait is some bell curve of P, with its peak probably somewhere around P=0.5 (or at least neither P=0 nor P=1). The fact that IQ-affecting environmental differences exist only rules out P=1, which maybe changes the posterior expectation of P from 0.5 to 0.45, but not to 0.
After all, our prior was that we would almost certainly find environmental differences that affect IQ, so finding them can’t cause that much of an update.
And if we haven’t even proven that the environmental differences affect IQ, only that they exist, then we shouldn’t update at all. Our prior for that was basically 1: any two groups will have some environmental difference (food, language, location...), so the existence of those differences can’t be evidence either way.
I don’t exactly know what you’re disagreeing with. I did not say that genetic difference is zero.
This is not a binary question as you seem to treat it. We need a probability distribution over “what difference in average IQ two groups in these two environments would have, if they were genetically identical”. And then depending on our beliefs about that, we could deduce that the genetic differences are a significant contributor, or that there is zero contribution, or even that “low-IQ” group has the superior genes.
The kinds of environmental differences we’re talking about are things like poverty, discrimination, etc. I assume that their effect on IQ has been observed, at least for some of them.
Now, I don’t actually know what that distribution looks like. It could really be very insignificant. But if Harris does not make a good effort to evaluate this distribution and then update his P(“inferior genes”) accordingly, then he is making an error.
Somehow, whenever I see people link to that, I end up unimpressed.
All this discussion seems insufficiently specific to make actual progress.
Obviously there are imaginable states of affairs in which our best estimate of genetic differences should be very close to zero. (E.g.: Observed overall differences small, many environmental effects found and well understood, best estimate of total impact of all known environmental effects very close to observed overall difference.) Call this proposition “P0”.
Obviously there are imaginable states of affairs in which our best estimate of genetic differences should be rather large. (E.g.: Observed overall differences large, environmental effects looked for but few found to have any supporting evidence, best estimate of total impact of all known environmental effects much smaller than observed overall difference.) Call this proposition “P1”.
And obviously what we should think about this (if we think about it at all) depends a great deal on the details of the actual evidence: how big the various known effects are, how hard researchers have tried to make IQ (or whatever) be insensitive to many environmental factors, how much we trust any given bit of research not to be perturbed by the researchers’ prior prejudices, etc., etc., etc.
So far as I can tell, zulupineapple and Jacobian don’t disagree with any of that. I haven’t looked into the Harris/Klein affair much, but my guess is that they and the other people who have weighed in also don’t disagree with any of that.
But so much of the discussion—including pretty much everything above—seems to consist, modulo outright mistakes, of one person reiterating P0 and another reiterating P1. So, e.g., zulupineapple points out that there are known environmental factors (so far this is just P0) and then says “At this point the hypothesis that these environmental differences explain all of the IQ differences, and that we know nothing about the genetic differences, becomes very likely”. Well, no, at some point that happens but to know whether we’re at that point yet we’d need to know more about the environmental differences and more about the observations they’re meant to explain. And then Jacobian points out that we have some prior for what the relevant differences are and the effect of learning about environmental factors just shifts our probability distribution rather than ramming it all the way to 0. That’s more or less just P1. Then zulupineapple comes back, reaffirms that we should be adjusting probability distributions, and says that depending on our prior we might end up with an estimate of 0. That’s just P0 again.
Maybe Harris and Klein are also just reiterating P0 and P1, in which case what needs pointing out is that they need to engage with the details of the evidence. Maybe at least one of them is actually engaging with those details. But in either case, just repeating “P0! P1! P0! P1!” achieves nothing useful.
(I am not saying that anyone ought to be digging further into the evidence and trying to do better than P0 and P1. That might be a bad idea—one might e.g. decide that the chance of finding anything genuinely actionable is small, and that the most likely outcome is simply becoming a pariah to some fraction of the population for political reasons. But if it’s worth getting into this argument at all then I think what’s worth doing will have to involve getting more concrete than just P0 and P1.)
No, you’re missing the point. I have very little interest in whether P1 or P0 or some P2 is true (and I don’t really see Jacob strongly favoring one of those either).
Instead, my bold claim is that Harris is not actually evaluating the environmental effects. He says that he uses the “default hypothesis”, but that only makes sense if you have zero information about the environmental differences, which is not the case. Ignoring data you have to make some conclusions look more reasonable is an error.
Now, on the object level, I admit that I favor P0, because the idea of genetic differences doesn’t really make much sense to me. Why should they be there? Because only smart people managed to migrate out of Africa? Mabe by pure chance? Also, it seems to me that there are some hard-to-measure environmental factors, so it’s not surprising if the measured part of environmental contributions is small. But I actually know very little about this issue.
I think you have misunderstood at least one thing: P0 and P1 are definitely both true. (They are propositions of the form “there are imaginable states of affairs such that …”.)
Once again, I don’t know very exactly what Harris and Klein have said, so I can’t easily tell what if anything he’s doing with the environmental effects. Are you saying that he thinks there are none? (I am not a big fan of Harris, but I would be astonished if he were being that stupid.) If not, it’s not clear to me what specific “serious error” you think he is making.
Your original comment doesn’t help me here. It observes that there are environmental effects (which, again, surely Harris doesn’t deny) and then jumps straight to saying that “the hypothesis that these environmental differences explain all of the IQ differences, and that we know nothing about the genetic differences, becomes very likely”—and I don’t understand where that comes from. I mean, sure, it could well be true that the environmental differences explain everything. But it seems like you jump straight from “there are lots of environmental factors” to “environmental differences probably explain everything” and I just don’t see how you can do that without actually engaging with the details of the available evidence.
(Once again, I’m not saying that you should do that. Only that without doing that, I don’t see how you can reach the conclusion you say you do.)
Of course not, that would be too easy. He does, at some point, explicitly acknowledge that environmental effects exist and are “very important”. And then he proceeds to do nothing with those effects. If you admit that a factor is very important, but then arrive at the same conclusions as someone who believes that the factor has 0 effect, that is still a problem.
I imagine the thinking goes like this. He observes that there are relevant factors X, Y, Z. He notices that Z has a lot of uncertainty, or is hard to work with, or ect. Then he decides that he will look at X and Y in isolation. And then he assumes that whatever conclusions X, Y have lead him to, actually have some bearing on the real world. Depending on Z this may or may not be the case. If it happens that Z really is 0, then you arrive at the correct conclusion, but even then, the path you took to get there is still wrong.
Of course, all of this is very hard to talk about when nobody gives their actual probability estimates (and giving probability estimates is also very hard). In particular this is because the value of P(“inferior genes”) doesn’t seem central to Harris. There is a good chance that I’m misreading him and that his estimate of P(“inferior genes”) is not as high as I assume it to be, and that he really is honestly updating on the environmental differences.
Still, the claim that Harris is making an error seems more likely to me. At least now you better understand what error I’m accusing him of? (By the way, I’m also accusing him of the error pointed out by RamblinDash, but didn’t want to duplicate it).