Race, Gender and IQ

In modern-day America, anyone arguing that the difference in average IQ between blacks and whites is part of the reason for the difference in average outcomes risks accusation of racism. Anyone arguing that the difference in the distribution of IQ between men and women is part of the reason that there are more men than women with elite positions in fields such as mathematics risks being accused of sexism. Examples of the risk of publicly offering  such ideas are provided by the cases of James Watson and Lawrence Summers. Watson, who received a Nobel prize for his role in the discovery of the nature of DNA, arguably the most important biological breakthrough of the century, was so careless as to tell the Times that he was "inherently gloomy about the prospect of Africa" because "all our social policies are based on the fact that their intelligence is the same as ours - whereas all the testing says not really". He was attacked ferociously for the statement, accused of prejudice, stripped of titles and positions.

Prejudice is belief held without evidence. Watson’s view may have been mistaken but there was evidence to support it, since the average measured IQ in African countries was indeed strikingly below that in European countries. His attackers, so far as I could tell, had no evidence in support of their view, were acting on pure prejudice.

Summers, then president of Harvard, commenting in an academic talk on the small numbers of women in elite academic positions in fields such as mathematics, offered several possible explanations. One of them was that although the average IQ of men and women was about the same, female IQ had a tighter distribution than male IQ. That would imply fewer women than men far out on the upper tail of the distribution, where Harvard math and physics professors are located. He was fiercely attacked for mentioning that possibility, forced out of his position at Harvard at least in part as a result. Again there was evidence for the claim, no evidence against.

The result of suppressing arguments for an unpopular view is that nobody knows what conclusion would come out of an open debate, although many may find it prudent to pretend to. Until very recently, the only convincing argument I had seen against the claim of lower African genetic IQ was Thomas Sowell’s observation¹ that the average family income of immigrants to the U.S. from the West Indies reached the U.S. average in one generation. West Indians are blacker than Afro-Americans in both their genes and their skin color, so if Afro-Americans did badly because of their African genes West Indian immigrants should do worse, and similarly if the reason was discrimination. Sowell offered instead an explanation based on the different cultures produced by differences between West Indian and North American slavery.²

I have now found more and better arguments against the hereditarian explanation of racial differences.³ Chanda Chisala is a Zambian immigrant who, like Sowell, is happy to engage in arguments on unfashionable subjects. His main topic is not Afro-American IQ but African IQ. He offers several independent lines of evidence to show that its low measured value, variously claimed to be 70 or 80, cannot be right.

One part of his evidence is the academic performance of African immigrants in first world countries where they are exposed to a first world environment, physical and educational. U.K. data on student performance is available not merely for racial groups conventionally defined but for linguistic subgroups within those populations. Africans on average do not do particularly well but a number of the African subgroups, including the two largest Nigerian tribes, Igbo and Yoruba, substantially outperform the native English, in some cases outperform East Asians as well.

Chisala’s U.S. evidence is more anecdotal. One year, a single college applicant in the U.S. was accepted by all eight Ivy League schools. He was a Nigerian immigrant. Another Nigerian immigrant is a serial entrepreneur who invented a computer application, founded a company, and sold it to Apple for an estimated billion dollars.⁴ Black students in elite universities are African or West Indian immigrants or their children in numbers far out of proportion to their share of the population.⁵ In at least one context where data on school performance happen to be available, black refugee immigrants, not native speakers of English, substantially outperformed Afro-Americans. That is the opposite of the result one would expect if Africans were genetically inferior in intelligence to whites, since Afro-Americans, unlike Africans, have significant white ancestry.

Chisala’s second line of argument is that African performance in checkers and Scrabble competition would be impossible if African average IQ were anything like as low as the estimates. While success in Scrabble at low levels depends in large part on vocabulary, the critical skill in high level competition is the ability to do the mental arithmetic needed to decide which play will give the player the most points and his opponent the fewest. Top white players have very high IQ’s; many are mathematicians. Yet a substantial fraction of the top players of English language Scrabble, including at least one world champion, are from Nigeria.

 In 2015, of the ten top players in the French Scrabble championship, three were from France, three from Gabon, three more from other African countries. Gabon is an ex-French colony with a population of 1.7 million. If one believes Richard Lynn’s figures on its IQ average and standard deviation there should not be a single person in the country close to the intelligence level of top Scrabble players. The figures on Nigerian IQ should make it very nearly impossible that Nigeria could have as many of the world’s top players of English Scrabble as it does if those estimates were close to correct.

A substantial fraction of the world’s top players of checkers, including some at the very highest level, are Africans. They do not do nearly as well at chess. Chisala’s explanation is that for chess, unlike Scrabble or checkers, playing at the highest level requires extensive instruction in the literature of the game, so much so that Bobby Fisher found it necessary to learn Russian in order to read the Russian chess literature. Few Africans have the opportunity for that sort of training. Russia has dominated modern chess competition at the highest level not because Russians are smarter than other people but because the Soviet Union chose, for purposes of international prestige, to put a lot of resources into subsidizing the training of its chess players. They put resources into checkers for the same reason only to find their dominance challenged by players from Africa.

The evidence Chisala offers does not tell us whether the average African genetic IQ is 95, 100, or 105, but it is clearly not 70 or 80. That conclusion is one that those skeptical of the hereditarian position will be happy with. Other parts of his argument are not. In the process of arguing that Scrabble performance at the high end requires a high IQ, Chisala takes on the issue that got Lawrence Summers in trouble, the effect of the difference between the male and female IQ distributions.

Explanations sometimes offered for why top physicists and mathematicians are almost all men are that women are culturally discouraged from entering such fields or discriminated against in them. That does not work for Scrabble, since more women than men play it and a large minority of the qualifiers to the North American Scrabble championships are women. Yet only about five percent of the highest rated players are women and no woman yet has won the world championship. As Chisala puts it,

This rising gender disparity as you go higher in expert Scrabble is a big win for the hereditarian corner of the gender-and-intelligence debate.

He goes on to write:

However, as we have seen many times in this research, a big win for the hereditarian side comes with a hidden pact with the devil: a victory in the gender-and-intelligence debate logically implies a decisive loss in the race-and-intelligence debate (you truly can’t have your cake and eat it in this world). How is it that black Africans, who (on average) are supposed to be about 30 IQ points below white women and supposedly have lower visuospatial or mathematical intelligence and even lower variance in their intelligence distribution, can achieve what has been accepted as statistically impossible for white women – outperforming white men – …

Chisala’s evidence that the genetic IQ of Africans is comparable to that of whites raises the puzzle of why Afro-American IQ apparently is not. One possibility is that observed lower IQ is due to environment rather than genetics. Chisala rejects that explanation, in part on evidence that the children of wealthy American blacks do less well than the children of poor whites despite what one would expect to be a more favorable environment, as well as evidence that African refugees from much less favorable environments outperform American blacks. He offers instead a genetic explanation.⁶ He conjectures that a feature of African genetics makes Africans more vulnerable than whites to unfavorable mutations and that such mutations were imported into the Afro-American gene pool early on by crosses with poor whites. I find his arguments for that conjecture less convincing than his arguments against the genetic inferiority of Africans, which leaves the puzzle of Afro-America IQ.

A possible explanation for part of it is vitamin D deficiency. Dark skin, the adaptation to a high sunlight environment by which blacks are commonly recognized, results in less conversion of sunlight to vitamin D. Milk in the U.S. is vitamin D fortified but a substantial fraction of Afro-Americans are lactose intolerant and so unlikely to drink milk.⁷ It follows that Afro-Americans are considerably more likely than whites to suffer from Vitamin D deficiency. There is evidence  linking vitamin D deficiency in pregnant women to lower IQ in their children.

How might one combine that speculation with Chisala’s evidence on the academic performance of African immigrants to the U.K.? The answer may be that a large fraction of the immigrants in question were born in an environment where their mothers were exposed to the level of sunlight they were adapted to. If that is the whole story, the next generation may not do as well. Unlike most other high latitude western countries the UK does not fortify any staple food items with vitamin D, aside from a small amount added to margarine.

Part of what I like about Chisala is that he has taught me something I did not know: Having read him I am now confident that African genetic IQ is not substantially lower than European. I also like his approach to arguing. He treats Lynn and Jensen, probably the two most prominent of the hereditarian scholars, not as wicked racists but as fellow scholars who have, for understandable reasons, reached mistaken conclusions.

What makes his work more persuasive than that of other critics of the hereditarian view of racial IQ is that he takes the other side’s arguments seriously. Too many of the attacks on the hereditarian position are on the level of the claim that some races cannot have a lower average IQ than others because there is no such thing as race, true in some technical sense but irrelevant to questions about the average IQ of races as conventionally defined, or the claim that what IQ tests measure doesn’t matter, demonstrably false given its correlation with things that do matter.⁸ The best arguments I had seen prior to reading Chisala offer some evidence against the position but not very strong evidence.⁹ That is the consequence of arguing in an environment where critics of the hereditarian position can be confident that most of their audience will never see the other side’s arguments.

Each of Chisala’s webbed essays is followed by a long thread of comments, many trying to explain away his evidence. He responds, in the comments or the next essay, by carefully examining each explanation and showing why it cannot be adequate.

His rebuttals are entertaining as well as convincing. Responding to the argument that Africans who decide to migrate to the U.K. are a select group, much more intelligent than the African average, he offers statistics showing that many are poor, few have high status careers. He also writes, responding to one critic:

I do not really know how it works in Jamaica, but I am quite confident that realizing that life is better in a very rich country than in your poor country is never exactly the most g-loaded epiphany among Africans.

Nature vs Nurture: A Natural Experiment

From 1970-1980 a large number of Korean-American children were placed for adoption by an agency which assigned them at random to adoptive families.¹⁰ That meant that any correlation between characteristics of the children as adults and characteristics of the families, such as maternal education, socio-economic status, or income, would be due to environment not genetics. By comparing the strength of the relation between characteristics of parents and adoptive children with the corresponding figure for parents and biological children raised by those parents, one can get at least an estimate of how much of the relation comes from which cause.

The conclusion is striking. An increase of one year in maternal education produces an increase of only .07 years in the education of an adoptive child but an effect four times as large on the education of a biological child. Similar results apply to a variety of other characteristics. It looks as though being brought up by well off or well-educated parents is indeed an advantage but a considerably smaller advantage than being the biological child of such parents.

One qualification to that result is that all of the adoptive families had to be certified by the adoption agency as suitable to adopt. That cut off some of the lower tail of the distribution of family environments; an alcoholic unmarried mother would be unlikely to qualify. And they had to be families that wanted to adopt, which again would eliminate some. But at least over the range of environments in the sample, nurture seems to be a good deal less important than nature.

The study cannot distinguish a relation due to shared genetics from one due to pre-natal environment; arguably, better educated and higher income mothers are in better condition during pregnancy, which could result in better children for (pre-natal) environmental reasons rather than genetic reasons. That does not affect the absolute level of the effect for adoptive children but might make the genetic contribution to the difference between adoptive and biological look larger than it really is.

Ethnic Cleansing, Other Horrors, and the Racial IQ Controversy

"It is never too much to remember how much ethnic cleansing was made in the past based on "scientific evidence" that some races were "not as intelligent as ours"..."

(from a comment on my blog)

It is a common claim, but I cannot find much evidence for it. Ethnic cleansing in Yugoslavia, where the term originated, had nothing to do with scientific evidence, real or bogus, about the relative intelligence of races; in some cases the cleansers and their victims differed only in whether their ancestors had or had not converted to Islam in the distant past. In others, the justification offered for the cleansing was "they have taken our land by immigrating and having more babies than we did and we want it back."

What about the Holocaust? Some Nazis made claims about Jewish inferiority but the basis for their anti-semitism was the idea that Jews were race enemies, in which case the more intelligent they were, the more dangerous; one can see that clearly in Henry Ford's less malevolent version of anti-semitism. In the post-war period, the largest race killings have been the Hutu/Tutsi conflicts in southern Africa; it is hard to believe that any significant amount of it was motivated by evidence of IQ differences between the two groups and the killing has gone in both directions.

If we shift the subject from killing to enslaving, the case becomes a little stronger. One argument used against freeing black slaves was that they were less intelligent, so unable to run their lives themselves, although it is hard to see that as a plausible argument for enslaving them in the first place. One justification offered for that was that it exposed them to Christianity, which presumes that they are at least sufficiently equal to have souls worth saving. But the main justification I have seen offered, insofar as any was needed beyond the usefulness of slavery to slave owners, was biblical, the "sons of Ham" argument. And of course black slavery, in the New World and earlier in the Islamic world, long predates the invention if IQ. In classical antiquity, slaves were frequently of the same ethnic stock as their owners.¹¹

When I invited readers of my blog to submit any historical example of genocide, ethnic cleansing, or slavery where either the main reason or the main justification offered was scientific or pseudo-scientific evidence that the victims were, on average, less intelligent than the perpetrators, the best answer I got was the case of the Nazis killing Slavs on the grounds that they were inferior to the Germans, untermenschen. But the main reason, pretty clearly, was that the Germans needed lebensraum and Slavs were occupying the real estate they wanted.

1. In Ethnic America.

2. Judging by Chisala’s account, Sowell later modified the theory, still attributing the result to culture but with a different explanation of its origin.

3. An archive of his writing.

4. Chinedu Echureo, the inventor of HopStop.

5. “While about 8 percent, or about 530, of Harvard's undergraduates were black, Lani Guinier, a Harvard law professor, and Henry Louis Gates Jr., the chairman of Harvard's African and African-American studies department, pointed out that the majority of them -- perhaps as many as two-thirds -- were West Indian and African immigrants or their children, or to a lesser extent, children of biracial couples.” (Top Colleges Take More Blacks, but Which Ones?, NYT June 24, 2004)

6. Curious readers will find it, and much else, in the series that starts with https://www.unz.com/article/the-iq-gap-is-no-longer-a-black-and-white-issue/ and goes on through eight more essays.

7. Some sources claim 75-80%, others a much lower rate.

8. For data on the subject see The Bell Curve, Part II.

9. One used data on the illegitimate children of Afro-American servicemen stationed in Germany after the end of WWII, ignoring the fact that the fathers were not a random sample of Afro-American males. Another observed that differences in school performance between white and black students could be eliminated by a regression that controlled for differences in parental income, home environment, and the like — all to some degree proxies for parental IQ.

10. My source for this section is Bruce Sacerdote, “What Happens When We Randomly Assign Children to Families?”

11. Arisotle argued that some people were natural slaves, hence slavery was not always unnatural, but not that that provided a justification for all actual slavery.