Even if cultural factors are sufficient, in themselves, to explain the black-white IQ difference, it remains more probable that whites tend to have a higher IQ by reason of genetic factors, and East Asians even more so.
This should be obvious: a person’s total IQ is going to be the sum of the effects of cultural factors plus genetic factors. But “the sum is higher for whites” is more likely given the hypothesis “whites have more of an IQ contribution from genetic factors” than given the hypothesis “blacks have more of an IQ contribution from genetic factors”. Therefore, if our priors for the two were equal, which presumably they are, then after updating on the evidence, it is more likely that whites have more of a contribution to IQ from genetic factors.
I’m not sure that this is the case, given that the confound has a known direction and unknown magnitude.
Back to Smith, Jones, and Spanish treasure: let’s assume that we have an uncontroversial measure of their wealth differences just after Smith sold. (Let’s say $50,000.) We have a detailed description of the treasure Smith found, but very little market data on which to base an estimation of what she sold them for. It seems that ceteris paribus, if our uninformed estimation of the treasure is >$50,000, Jones is likelier to have a higher non-pirate gold income, and if our uninformed estimation of the treasure is <$50,000, Smith is likelier to.
Whites and blacks both have a cultural contribution to IQ. So to make your example work, we have to say that Smith and Jones both found treasure, but in unequal amounts. Let’s say that our estimate is that Smith found treasure approximately worth $50,000, and Jones found treasure approximately worth $10,000. If the difference in their wealth is exactly $50,000, then most likely Smith was richer in the first place, by approximately $10,000.
In order to say that Jones was most likely richer, the difference in their wealth would have to be under $40,000, or the difference between our estimates of the treasures found by Smith and Jones.
I agree with this reasoning, although it does not contradict my general reasoning: it is much like the fact that if you find evidence that someone was murdered (as opposed to dying an accidental death), this will increase the chances that Smith is a murderer, but then if you find very specific evidence, the chance that Smith is a murderer may go down below what it was originally.
However, notice that in order to end up saying that blacks and whites are equally likely to have a greater genetic component to their intelligence, you must say that your estimate of the average demographic difference is EXACTLY equal to the difference between your estimates of the cultural components of their average IQs. And if you say this, I will say that you wrote it on the bottom line, before you estimated the cultural components.
And if you don’t say this, you have to assert one or the other: it is more likely that whites have a greater genetic component, or it is more likely that blacks do. It is not equally likely.
And if you don’t say this, you have to assert one or the other: it is more likely that whites have a greater genetic component, or it is more likely that blacks do. It is not equally likely.
Often when people say “equally likely” they mean “I don’t know enough to credibly estimate which one is greater, the probability distributions just overlap too much.” (Yes, the ‘bottom line’ idea is more relevant here. It’s a political minefield.)
But that’s the point of my general argument: if you know that whites average a higher IQ score, but not necessarily by how much (say because you haven’t investigated), and you also know that there is a cultural component for both whites and blacks, but you don’t know how much it is for each, then you should simply say that it is more likely (but not certain) that whites have a higher genetic component.
I mean “equally likely” in wedrifid’s sense: not that, having done a proper Bayesian analysis on all evidence, I may set the probability of p(W>B)=p(B>W}=.5 (assuming intelligence works in such a way that this implied division into genetic and environmental components makes sense), but that 1) I don’t know enough about Spanish gold to make an informed judgement and 2) my rough estimate is that “I could see it going either way”—something inherent in saying that environmental differences are “sufficient to explain” extant differences. So actually forming beliefs about these relative levels is both insufficiently grounded and unnecessary.
I suppose if I had to write some median expectation it’s that they’re equal in the sense that we would regard any other two things in the phenomenal world of everyday experience equal—when you see two jars of peanut butter of the same brand and size next to each other on a shelf in the supermarket, it’s vanishingly unlikely that they have exaaaactly the same amount of peanut butter, but it’s close enough to use the word.
I don’t think this is really a case of writing things down on the bottom line. What reason would there be to suppose ex ante that these arbitrarily constructed groups differ to some more-than-jars-of-peanut-butter degree? Is there some selective pressure for intelligence that exists above the Sahara but not below it (more obvious than counter-just-so-stories we could construct?) Cet par I expect a population of chimpanzees or orangutans in one region to be peanut butter equal in intelligence to those in another region, and we have lower intraspecific SNP variation than other apes.
“I could see it going either way” is consistent with having a best estimate that goes one way rather than another.
Just as you have the Flynn effect with intelligence, so average height has also been increasing. Would you say the same thing about height, that the average height of white people and black people has no significant genetic difference, but it is basically all cultural? If not, what is the difference?
In any case, both height and intelligence are subject to sexual selection, not merely ordinary natural selection. And where you have sexual selection, one would indeed expect to find substantial differences between diverse populations: for example, it would not be at all surprising to find significantly different peacock tails among peacock populations that were separated for thousands of years. You will find these significant differences because there are so many other factors affecting sexual preference; to the degree that you have a sexual preference for smarter people, you are neglecting taller people (unless these are 100% correlated, which they are not), and to the degree that you have a sexual preference for taller people, you are neglecting smarter people. So one just-so-story would be that black people preferred taller people more (note the basketball players) and so preferred more intelligent people less. This just-so-story would be supported even more by the fact that the Japanese are even shorter, and still more intelligent.
Granted, that remains a just-so-story. But yes, I would expect “ex ante” to find significant genetic differences between races in intelligence, along with other factors like height.
Even if cultural factors are sufficient, in themselves, to explain the black-white IQ difference, it remains more probable that whites tend to have a higher IQ by reason of genetic factors, and East Asians even more so.
This should be obvious: a person’s total IQ is going to be the sum of the effects of cultural factors plus genetic factors. But “the sum is higher for whites” is more likely given the hypothesis “whites have more of an IQ contribution from genetic factors” than given the hypothesis “blacks have more of an IQ contribution from genetic factors”. Therefore, if our priors for the two were equal, which presumably they are, then after updating on the evidence, it is more likely that whites have more of a contribution to IQ from genetic factors.
I’m not sure that this is the case, given that the confound has a known direction and unknown magnitude.
Back to Smith, Jones, and Spanish treasure: let’s assume that we have an uncontroversial measure of their wealth differences just after Smith sold. (Let’s say $50,000.) We have a detailed description of the treasure Smith found, but very little market data on which to base an estimation of what she sold them for. It seems that ceteris paribus, if our uninformed estimation of the treasure is >$50,000, Jones is likelier to have a higher non-pirate gold income, and if our uninformed estimation of the treasure is <$50,000, Smith is likelier to.
Whites and blacks both have a cultural contribution to IQ. So to make your example work, we have to say that Smith and Jones both found treasure, but in unequal amounts. Let’s say that our estimate is that Smith found treasure approximately worth $50,000, and Jones found treasure approximately worth $10,000. If the difference in their wealth is exactly $50,000, then most likely Smith was richer in the first place, by approximately $10,000.
In order to say that Jones was most likely richer, the difference in their wealth would have to be under $40,000, or the difference between our estimates of the treasures found by Smith and Jones.
I agree with this reasoning, although it does not contradict my general reasoning: it is much like the fact that if you find evidence that someone was murdered (as opposed to dying an accidental death), this will increase the chances that Smith is a murderer, but then if you find very specific evidence, the chance that Smith is a murderer may go down below what it was originally.
However, notice that in order to end up saying that blacks and whites are equally likely to have a greater genetic component to their intelligence, you must say that your estimate of the average demographic difference is EXACTLY equal to the difference between your estimates of the cultural components of their average IQs. And if you say this, I will say that you wrote it on the bottom line, before you estimated the cultural components.
And if you don’t say this, you have to assert one or the other: it is more likely that whites have a greater genetic component, or it is more likely that blacks do. It is not equally likely.
Often when people say “equally likely” they mean “I don’t know enough to credibly estimate which one is greater, the probability distributions just overlap too much.” (Yes, the ‘bottom line’ idea is more relevant here. It’s a political minefield.)
But that’s the point of my general argument: if you know that whites average a higher IQ score, but not necessarily by how much (say because you haven’t investigated), and you also know that there is a cultural component for both whites and blacks, but you don’t know how much it is for each, then you should simply say that it is more likely (but not certain) that whites have a higher genetic component.
I agree.
I mean “equally likely” in wedrifid’s sense: not that, having done a proper Bayesian analysis on all evidence, I may set the probability of p(W>B)=p(B>W}=.5 (assuming intelligence works in such a way that this implied division into genetic and environmental components makes sense), but that 1) I don’t know enough about Spanish gold to make an informed judgement and 2) my rough estimate is that “I could see it going either way”—something inherent in saying that environmental differences are “sufficient to explain” extant differences. So actually forming beliefs about these relative levels is both insufficiently grounded and unnecessary.
I suppose if I had to write some median expectation it’s that they’re equal in the sense that we would regard any other two things in the phenomenal world of everyday experience equal—when you see two jars of peanut butter of the same brand and size next to each other on a shelf in the supermarket, it’s vanishingly unlikely that they have exaaaactly the same amount of peanut butter, but it’s close enough to use the word.
I don’t think this is really a case of writing things down on the bottom line. What reason would there be to suppose ex ante that these arbitrarily constructed groups differ to some more-than-jars-of-peanut-butter degree? Is there some selective pressure for intelligence that exists above the Sahara but not below it (more obvious than counter-just-so-stories we could construct?) Cet par I expect a population of chimpanzees or orangutans in one region to be peanut butter equal in intelligence to those in another region, and we have lower intraspecific SNP variation than other apes.
“I could see it going either way” is consistent with having a best estimate that goes one way rather than another.
Just as you have the Flynn effect with intelligence, so average height has also been increasing. Would you say the same thing about height, that the average height of white people and black people has no significant genetic difference, but it is basically all cultural? If not, what is the difference?
In any case, both height and intelligence are subject to sexual selection, not merely ordinary natural selection. And where you have sexual selection, one would indeed expect to find substantial differences between diverse populations: for example, it would not be at all surprising to find significantly different peacock tails among peacock populations that were separated for thousands of years. You will find these significant differences because there are so many other factors affecting sexual preference; to the degree that you have a sexual preference for smarter people, you are neglecting taller people (unless these are 100% correlated, which they are not), and to the degree that you have a sexual preference for taller people, you are neglecting smarter people. So one just-so-story would be that black people preferred taller people more (note the basketball players) and so preferred more intelligent people less. This just-so-story would be supported even more by the fact that the Japanese are even shorter, and still more intelligent.
Granted, that remains a just-so-story. But yes, I would expect “ex ante” to find significant genetic differences between races in intelligence, along with other factors like height.