Race, genes and IQ: Some observations



By J.J. Ray (M.A.; Ph.D.)


An area of discussion that REALLY offends the Leftist equality dogma is the idea that differences in intelligence are inborn and that differences in average group intelligence may therefore be inborn too. I realize, in fact, that in even mentioning this subject, I am taking a risk. As it says here:

In the past, many of the the strongest taboos regarded sexual matters. One can read almost the entire body of Victorian literature without seeing any explicit mention of that activity which enables the human race to reproduce itself, and which is a major preoccupation of the majority of human beings. Today, one can freely discuss most sexual topics in public.

A major taboo in today's world concerns any mention of genetic differences between the races, even when it is made plain that the differences are statistical rather than universal. The politically correct view is that the only physical difference between Negroes and Caucasians lies in the color of their skin. There are, of course, many other statistical differences between the physical attributes of blacks and whites. (For example: eye color, hair color, amount of body hair, age at menarche, and frequency of fraternal twins.) But the most serious taboo regards any suggestion that the well-known racial difference in average IQs is even partly due to genetic factors.

As psychometrics is my academic specialty, however, I have always taken an interest in studies of IQ and I have even summarized some of the relevant evidence and issues in the academic literature. See: Ray, J.J. (1972) Are all races equally intelligent? Or: When is knowledge knowledge? J. Human Relations 20, 71-75. I will therefore not attempt to rehash here the mountain of evidence for large race and group differences in IQ but will rather look at some of the issues that have been raised in response to that evidence. For those who need convincing about what the evidence shows, however, there is a recent and comprehensive downloadable reference here and a PDF version of the same online here. There is a more condensed treatment of the evidence here.

And, perhaps surprisingly, what you will read there is no longer academically marginalized stuff at all. I don't quite know whether to be pleased or disappointed but it seems that mainstream psychology is catching up with what psychometricians such as myself have been saying for years: That IQ is highly general, highly central, highly hereditary and of overwhelming importance in determining people's life-chances. Even a few years ago any claim to that effect would be very marginal within psychology and would expose anyone making it to all sorts of nasty accusations.

But you can now read it all not in some obscure academic journal or some Rightist source but in a 2004 issue (vol. 86 no. 1) of the American Psychological Association's most widely-circulated journal -- the Journal of Personality and Social Psychology. Article after article there sets out the importance of IQ. And for social psychologists to be taking an interest in such evidence is really amazing. Psychometricians have known all that stuff for years. It is the social psychologists who have been most resistant to such ideas. I fear that I have suddenly become mainstream! I guess that even an organization as Leftist as the American Psychological Association has to come to terms with the evidence eventually. I would never have predicted it, though.

The madness of the 60s must be waning at long last. Before the 60s the central importance of IQ was uncontroversial introductory textbook stuff in psychology but the radical takeover of the universities from the 1960s onward and its inevitable accompanying baggage about "all men are equal" caused the whole idea of IQ to be marginalized for many years.

And a debate on "Slate" mentions some of the issues involved. Excerpt from Steven Pinker:

Judith Harris was among the first to call attention to the fact that we know much less than we think we do about "environmental" influences on personality and behavior. In The Nurture Assumption she points out that once you subtract out the effects of shared genes on correlations between parenting practices and children's outcomes (which few psychologists do), there isn't much evidence that parenting shapes children's personalities. It's not all in the genes, but the part that isn't from the genes isn't from parents either (siblings separated at birth end up no more different than siblings reared together, and adopted siblings end up not similar at all)

The big issue, of course, is how much of anyone's general intelligence is genetically determined. Leftists often go so far as to say: "None" but psychometricians and geneticists have been reporting results for nearly a century now that show IQ to be predominantly genetically inherited.

Faced with the evidence, Leftists sometimes try to discredit it by asking whether IQ tests really measure intelligence. And the answer of course is that everybody defines intelligence in their own way. I know some people who think that owning a bull-terrier dog is highly intelligent.

But if the concept of intelligence is not precise the concept of IQ is. IQ indexes 'g', which is general problem-solving ability. As Binet discovered over a century ago, it just so happens that people who are good at solving one sort of problem tend to be good at solving all sorts of other problems -- and it is that ability which IQ tests measure and are founded upon.

The Flynn Effect: One of the most interesting things to have turned up in recent years is the "Flynn effect" -- named after Prof. Jim Flynn, who is generally credited with being the first to note it (He wasn't. Richard Lynn was). What Flynn has rightly publicized at great length is that average scores on IQ tests have been rising steadily over the last century. The young people of today seem to be much smarter than their grandparents.

How do we explain that? The participants in the "Slate" debate did not think that they could explain it but I think I can if I put my sociologist's hat on (I also taught sociology for 12 years at a major Australian university):

I see the Flynn effect as just one example of the way modernization has improved various indices of people's physical health and well-being. People also now (for instance) live longer and grow taller than they did a century ago. And IQ is related to general physical functioning. If the body as a whole is working well, the brain should in general be working well too. The brain is after all just another part of the body. And the Terman & Oden (1947) "Genetic studies of genius" did show that high IQ children grew up to be taller, healthier, better adjusted etc.

Note also this academic article on IQ.

Abstract:

"Virtually all indicators of physical health and mental competence favor persons of higher socioeconomic status (SES). Conventional theories in the social sciences assume that the material disadvantages of lower SES are primarily responsible for these inequalities, either directly or by inducing psychosocial harm. These theories cannot explain, however, why the relation between SES and health outcomes (knowledge, behavior, morbidity, and mortality) is not only remarkably general across time, place, disease, and kind of health system but also so finely graded up the entire SES continuum. Epidemiologists have therefore posited, but not yet identified, a more general "fundamental cause" of health inequalities. This article concatenates various bodies of evidence to demonstrate that differences in general intelligence (g) may be that fundamental cause."

(From the very mainstream journal: Journal of Personality and Social Psychology, 2004, Vol. 86, No. 1, 174-199)

But why has modernization improved many health and wellbeing indices? The obvious factor is improved medical care generally but two areas of medical care may be particularly important: Mass vaccination campaigns and improved perinatal care. Many illnesses can have a damaging effect on the brain as well on the rest of the body so preventing major illnesses through vaccination should be generally beneficial. And by improved perinatal care I mean better obstetric services (including a now very high rate of caesarians) and more advice and support for new mothers to enable them to look after their babies better. But better nutrition, more widespread hygiene practices, piped water, efficient sewerage systems, basic public health measures, more stimulation by way of modern entertainment media and more years spent in the educational system could also of course play a role. The infant brain is known to develop more complex connections when subjected to a high level of stimulation and there is much in the modern world that is far more stimulating than the village or small-town life of yesteryear.

If I take my sociologist's hat off, however, and re-don my psychometrician's hat, there is another interesting explanation for the Flynn effect: It could be an "artifact" (not a real effect -- i.e. maybe real IQ did not rise at all). Why?

Because, although scores on all sorts of IQ subtests (puzzle categories) rose during the 20th century, they did not rise evenly. And the scores that rose least were for those problems that loaded most highly on 'g' (See e.g. here). The implication is that scores on a perfect measure of 'g' would not have risen at all.

So how do we explain that? There is no general agreement but the commonest explanation among psychometricians is that the rise in measured IQ reflects increasing test sophistication. Kids now spend MANY more years in the educational system than they once did and although there is probably little to show for that overall, kids DO get a lot of practice in passing tests of various sorts. And practice may not make perfect but it would be surprising if test-taking skills and strategies (such as guessing when you are not certain) were not improved by many years of extra practice at taking such tests.

But, whichever way you look at it, it is clear that the Flynn effect does not weaken the case for saying that IQ is substantially genetically determined. It simply suggests what are the circumstances for making the most of our genetic inheritance. And, sadly for those who hate the idea of genetic influences, the IQ increases have not closed the usual big gap between average black and white IQ levels. Negroes have forged ahead but whites have forged ahead too. And, if U.S. education results are any guide, the black-white IQ gap may even have widened in recent years.

Jewish IQ: I have had an interesting correspondence with Richard Lynn about Israeli IQ. He notes that Israelis of European origin (Ashkenazim) have an average IQ of about the European norm (100) whereas Israelis from the Arab lands (Sephardim) have the quite low average IQ of 88.

What does that say about Arab IQ? Seeing that those Jews who are racially mainly Arab ought to be at least no less intelligent than the parent Arab population, it suggests to me that Arabs in general are pretty low on intelligence.

The most interesting question, however, is why the Israeli Ashkenazim are not well ABOVE the European norm. As Rushton summarizes the recent American data: "The average IQ for African Americans was found to be lower than those for Latino, White, Asian, and Jewish Americans (85, 89, 103, 106, and 115, respectively)". So why do not Israeli Ashkenazis average 115 too? I am afraid that the obvious explanation is that it was mainly the foolish (idealistic?) Jews of European origin who have ended up in Israel. The smart ones are in New York.

Lynn points out, however, that the figure for Jews quoted by Rushton is based on limited sampling. Lynn believes that a figure of 108 is better substantiated. In statistician's terms, however, 108 is still quite a high figure (around half a standard deviation above the mean).

Update on Israeli IQ: Since I wrote the above the Israeli IQ picture has become a lot clearer. This article quotes IQ test results from Israeli army intakes -- and army intakes are a traditionally strong source of IQ norms, particularly where conscription prevails -- as it does in Israel. He points out that the Israeli army intakes average an IQ of 100 and relates that to the well-known fact that "Sephardim" (broadly defined) score much lower than that. The obvious deduction is that the Askenazi component of the intake is pulling the army average up so must themselves be scoring around 107 -- which is similar to what we find among Ashkenazim in NYC and elsewhere.

A second contribution comes from smart fraction theory. Israel shows enormously high competencies in all sorts of ways so the idea that their average IQ is unremarkable clashes with that. Smart fraction theory, however, shows that it is not the average IQ that matters to national wellbeing and achievement but rather the IQ of (say) the top 5% of the population. So in an ethnically mixed population, you could well have a very smart top 5% even though the average is low or unremarkable. And that describes Israel very well -- with the Ashkenazim providing that smart fraction.

The most comprehensive look at the black/white gap: But the really sensitive area for discussion as far as IQ is concerned is of course the IQ of American blacks. Since roughly the 1960s the long-standing scientific evidence that intelligence is highly heritable has come to be bitterly and arbitrarily dismissed by Leftists -- now that it is well-known that the same evidence also shows lower average scores for favoured Leftist groups such as blacks and people of lower socioeconomic status (Brand, 1996). The evidence of heritability is now simply denied as absurd or the standard of proof required for the evidence to be accepted is raised so high that no evidence would ever be sufficient (Ray, 1972a). The animosity to even the concept of intelligence has become so great that bans on intelligence testing in schools have been introduced in some American States.

But, if we are interested in the facts, the most authoritative book on the subject is undoubtedly the 2006 book: "Race differences in intelligence: An evolutionary analysis" by Richard Lynn. Review here.

The essential thing to note about this book is that it is NOT an expression of opinion. It is an attempt to do something far more difficult -- an attempt to gather together ALL the available scientific evidence on its topic. Let me give you a little personal anecdote to show you how hard that is.

Like Lynn, I am a psychometrician (specialist in psychological measurement) but my interest is in measuring attitudes and personality. And one of my interests is in how to measure ambition (what psychologists call achievement motivation). And roughly once a year somebody publishes a new set of questions designed to do that. But nobody ever seems to be aware of all the previous attempts in the same field. Typically, they seem to know of only two or three attempts to measure ambition in that way. On a couple of occasions, psychologists have published what they thought was a comprehensive survey of the literature in the field but the best of them could find (from memory) no more than 16 such articles in the academic literature. So a couple of years later I published a catalogue of such articles. And I found around 70 such!

How come? It is because the standard resources for searches of the academic literature are very imperfect. They miss heaps. You cannot instantly acquire a knowledge of the findings on a topic simply by doing a search. You have to be a specialist in the field who continually has an eye out for interesting findings and who systematically collects such findings over a period of many years. Richard Lynn is such a person in the field of IQ. Lynn's book is, in other words, about as authoritative as you can get. And in comparison with the measly 70 articles that I could find on my topic, Lynn records over 500 surveys of IQ.

So what the book tells us is not what Richard Lynn thinks. Lynn of course has his opinions and he does express them (he argues, for instance, that an evolutionary history of coping with cold winters selects for high intelligence) but that is not what the book is primarily about. What the book shows us is what the entire body of scientific research on the subject stretching back over the last 100 years or more has shown. And, as all psychometricians know, the findings are remarkably uniform. There is normally a huge gap between the average scores of African-origin populations and European-origin populations. Brilliant blacks do of course exist. The person whom I quote most on my blog is an African-American (Thomas Sowell). But brilliant (high IQ) people are simply much rarer in African-origin populations than in European ones. And all the studies of the genetics of IQ show its transmission to be overwhelmingly genetic.

Confronted with this now very old and very persistent finding, the usual response from those who feel challenged by it has been to dismiss IQ tests. They say that IQ scores mean nothing, do not measure intelligence and are of no importance generally. Lynn of course takes such claims seriously and devotes his opening chapter to such challenges. The essential thing that you need to know in evaluating such challenges is however very simple: IQ is a DISCOVERY, not a product of theory. The whole concept of IQ arose in the late 19th century when educationists began to notice a very strange thing: People who were good at solving one type of problem or puzzle also tended to be good at solving quite different puzzles and problems. There WAS such a thing as a general problem-solving ability. And it is for that reason that the scientific literature does not usually use the term "IQ". In the scientific literature, it is usually referred to as 'g' (short for "general factor"). And that is also why IQ tests normally are comprised of a whole series of quite different and apparently unrelated problems -- because problem-solving ability IS general, regardless of the sort of problem. And something as general as that is obviously of considerable importance.

I will not attempt here to survey comprehensively the various arguments that have been raised about the utility of IQ tests generally or about non-genetic explanations for the findings with Africans and others. That is what Lynn's book is for. Be assured, however, that all the possible objections are well known to experts in the field and have been extensively researched. It is a case of there being "nothing new under the sun" as far as theories of that kind are concerned and most such theories can be decisively rejected in the light of the research available. The one non-genetic but physical explanation for IQ differences that has stood up fairly well is nutrition. Good or bad nutrition in childhood can affect how well the brain develops and hence IQ. The brain is however pretty good at protecting itself so the differences observed due to nutrition are generally very small, much smaller than the black/white difference, for instance. The best diet in the world won't make a dummy into an Einstein nor will the best education or the best anything else. But if you want to get a doctorate it helps a lot if your father has one -- even if you don't live with him or know him.

The adoption test: Of particular interest on the subject of racial differences in IQ is an impressively scholarly article here by Glayde Whitney summarizing the results of the Minnesota study of transracial adoption.

The background of course is that researchers always find a huge gap (of about 15 IQ points) between the average IQ of American blacks and the average IQ of American whites. And American Leftists almost always attribute this to the poor upbringing that black children receive (and since that is not very complimentary to black mothers they then blame black "culture" -- and that, of course, is the fault of whites!).

So the obvious experiment to test the Leftist theory is to have black children adopted into white families and see what happens. Will they grow up with IQs at the same average level as whites? If upbringing is the key, they should. Some well-intentioned whites actually did just such an adoption program on a fairly large scale in Minnesota in the 1970s. The result years later? There was still that same old black/white gap in IQ when the children concerned had grown up. The implication is, as so many other studies suggest, that it is the African gene pool that is responsible for the lower black IQs.

There is an adoption study that focuses on income summarized here which gives similar results to studies of IQ. Excerpt:

The graph below is from a fascinating new paper, What Happens When We Randomly Assign Children to Families?, by Bruce Sacerdote. Holt's International Children's Services places children, primarily Koreans, with families in the United States. Holt has an interesting proviso to their adoption contract, conditional on being accepted into the program, children are randomly assigned. Sacerdote has collected data from children who were adopted between 1970-1980, and thus who today are in their mid 20's or 30's, and their adoptive parents.

The graph shows how parent income at the time of adoption relates to child income for the adopted and "biological" (non-adopted) children. The income of biological children increases strongly with parental income but the income of adoptive children is flat in parent income.

In other words, as with IQ, family environment had NO EFFECT on achievement. Kids adopted into high income households did no better than kids adopted into low income households. Only genetics made a difference: Very contrary to lots of popular assumptions and a bitter pill for Leftists to swallow but those are the facts. And, given that the measurement of income is a lot less controversial than the measurement of IQ, the concordance between income and IQ studies could well be seen as particularly impressive.

The DNA speaks: Under the influence of Leftist political correctness, a lot of biological scientists have in the past pooh-poohed the reality of race and said that all races are more or less the same genetically. It is interesting, therefore, that DNA research establishes what every honest observer has known all along -- that there are different races, that they are genetically different and that the differences in the genes correspond to how people generally group the races. Excerpt:

Scientists studying the DNA of 52 human groups from around the world have concluded that people belong to five principal groups corresponding to the major geographical regions of the world: Africa, Europe, Asia, Melanesia and the Americas. The study, based on scans of the whole human genome, is the most thorough to look for patterns corresponding to major geographical regions. These regions broadly correspond with popular notions of race, the researchers said in interviews. The researchers did not analyze genes but rather short segments of DNA known as markers, similar to those used in DNA fingerprinting tests, that have no apparent function in the body. "What this study says is that if you look at enough markers you can identify the geographic region a person comes from," said Dr. Kenneth Kidd of Yale University, an author of the report.

The issue of race and ethnicity has forced itself to biomedical researchers' attention because human populations have different patterns of disease, and advances in decoding DNA have made it possible to try and correlate disease with genetics. The study, published today in Science, finds that "self-reported population ancestry likely provides a suitable proxy for genetic ancestry." In other words, someone saying he is of European ancestry will have genetic similarities to other Europeans.

The new result is based on blood samples gathered from around the world as part of the Human Genome Diversity Project, though on a much less ambitious scale than originally intended. Dr. Feldman and his colleagues analyzed the DNA of more than 1,000 people at some 400 markers. Because the sites have no particular function, they are free to change or mutate without harming the individual, and can become quite different over the generations.

There is a later report of genetic research with similar conclusions here

Motivation: There is an excellent summary article here on the old chestnut that blacks do poorly on IQ tests because of lack of motivation. The truth is that blacks try harder: When given unlimited time to do tests, blacks tend to stick at it longer. All that seems to be forgotten in the latest bout of weird reasoning, however. Leftist psychologists now say that "Stereotype threat" causes the low scores. The claim is that blacks try less because they fear that their poor results will reflect badly on blacks generally. One would have thought that such fears would cause them to try HARDER but all that is brushed aside. The article concludes: "Lack of evidence and grave methodological defects haven't prevented the stereotype threat industry from taking off. Distortions are now pervasive."

National differences: The book on national differences in IQ by Richard Lynn and Tatu Vanhanen (IQ and The Wealth of Nations) is finally getting a bit of attention and their findings have also now been used academically (Voracek M. "National intelligence and suicide rate: an ecological study of 85 countries". Personality & Individual Differences, 2003). Lynn & Vanhanen show, of course, that national average IQs vary greatly and that the higher IQ nations are much more likely to be economically prosperous. The lowest averages are in Africa.

As my contribution to the discussion, I have uploaded to the web an article by Nathaniel Weyl which was written nearly 40 years ago and which is now very little known (though it is referred to here). It reports a large and comprehensive body of data on white Rhodesians -- as they then were. They were one of the most intelligent Caucasian populations ever -- now of course thoroughly dispersed and destroyed by the Mugabe regime. Weyl explains the selective pressures that produced such high IQs among whites in what is now Zimbabwe. Details here or here

Nutrition and IQ: It is an old claim that blacks have lower IQs because of their poor nutrition. Apparently fried chicken is really bad for you! Since American blacks have very low average IQs despite America's "obesity (overnutrition) epidemic" (in which blacks share), that has always been a rather desperate claim but there is a potential grain of truth in it. The effect of nutrition on IQ seems to be rather variable. The famous Dutch famine study showed that children born into famine conditions can have higher average IQs because all the weaker children die off. Under more normal conditions, however, about 5 IQ points can be added to average IQ by optimal nutrition (a full range of vitamins and minerals at all times). A 2004 United Nations report (about the "Micronutrient Initiative") has confirmed that -- acknowledging that the people of poor countries (mostly black) are less intelligent!

"But the most disturbing gap between countries with good and poor nutrition is in intelligence, said Cutberto Garza, a Cornell University professor who also leads the nutrition program at United Nations University. "A difference of five to seven IQ points doesn't sound like a lot, but you have to look at the tail ends of the (statistical) curve". *

The report, however, glides past the magnitude of the problem. It states, correctly, that about 5 IQ points can be added by optimal nutrition but neglects to mention that the gap between (say) some European and (say) some African populations is more than 20 points on average!


S.J. Gould: In their hatred of genetics and IQ, something Leftists cling to is a superficially clever book called The Mismeasure of Man by that smug old Leftist propagandist, Stephen Jay Gould. It is a book that would deceive no-one who knew anything about the field and totally misrepresents those who do but as more and more data on genetics and brain function emerge, the sheer stupidity of the work become more and more obvious. Here is a brief summary of Gould's lies and evasions and what the latest brain findings show. An older and more extensive demolition of Gould is here

The Bell Curve: The best known work on group differences in IQ is of course The Bell Curve by Murray & Herrnstein -- which has come under a huge amount of unscholarly attack. Murray himself commented in reply:

"I do not know how to explain the extraordinary discrepancy between what The Bell Curve actually says about race and what most commentators have said that the book says, except as the result of some sort of psychological projection onto our text. Other factors are at work as well. Michael Novak (who has written favorably about The Bell Curve) and Thomas Sowell (who has his criticisms of the book) have pointed out in similar terms that the Left has invested everything in a few core beliefs about society as the cause of problems, government as the solution, and the manipulability of the environment for reaching the goal of equality. For the Left, as Novak puts it, The Bell Curve's "message cannot be true, because much more is at stake than a particular set of arguments from psychological science. A this-worldly eschatological hope is at stake. The sin attributed to Herrnstein and Murray is theological: they destroy hope".

Sternberg's "triarchic" theory: One of the people best known among psychologists for disparaging the importance of IQ ('g' or general problem-solving ability) is Robert Sternberg. He is much less of a lightweight than Gould and his ilk and does acknowledge the reality of IQ but says that it is only one of three types of important mental functioning that can be measured.

But the other two he puts forward are pretty desperate proposals. The second one he himself summarizes as "street smarts" so is nothing more than knowledge of a particular culture or environment -- and nobody has ever disputed that you need both intelligence and knowledge to solve problems well. So while knowledge is important, to refer to it as an "ability" is evasive. And his third alternative is creativity -- which again seems reasonable at first. The problem with creativity, however, is that there appears to be no such thing. Different indices of creativity often fail to correlate with one another. You can be creative in one field and not in another. I myself, for instance, am highly creative at scientific writing or I would not have 250+ academic papers in print -- but I would not be able to write a novel for nuts. So although problem-solving ability is demonstrably general -- which is why we have the concept of IQ -- creativity is not. So Sternberg is still left with IQ as the single useful generalization about abilities.

And the criticisms of his work simply seem to have driven Sternberg to retreat further and further into dishonesty. He simply ignores whole bodies of data -- including things he had acknowledged in his own earlier work -- as Linda Gottfredson (PDF) points out.

The failure to hide IQ differences: As I mentioned earlier, the black-white gap in average IQ was once standard introductory psychology textbook stuff but heroic efforts have been made since the 60's to hide or explain away the difference. It is impressive, therefore, that confirmatory studies are still coming out. A huge and very careful study of mental abilities came out recently from Johns Hopkins University under the title: "Disparities in Cognitive Functioning by Race/Ethnicity in the Baltimore Memory Study". Blacks were found to have much lower scores than whites across the board. As the study was primarily of memory, the tests used were not all high loaders on 'g' (general intelligence or 'IQ') so the racial difference varied a fair bit from test to test but it was always there. The amusing thing was that the racial difference persisted depite heroic attempts by the researchers to remove it. They even did some things that an Australian would call "shonky" (con-men and frauds are "shonks"). For example, they removed the effect of social class variables such as wealth on their results. In other words, the scores of poorer people were "adjusted" upward. But wealth is a product of IQ! Smarter people get richer! And this particular study was of 50-70 year old people so any effect of intelligence on wealth would have had plenty of time to show up. If the researchers had used parental status indicators only it might have been more defensible. So the fact that the racial difference emerged despite such blatant attempts to mask it is testimony to how strong the difference is.

Policy implications? The only policy implication that I see as flowing from an acceptance of low average black IQ in a decent society is that we may often have to treat some blacks as we do any other handicapped people -- kindly. On the other hand, a policy founded on the claim that the differences do not exist -- as "Affimative action" is -- must in the circumstances be a cruel hoax that imposes unrealistic expectations on many blacks, discriminates unfairly against many individual whites and discredits the achievements of the many blacks who can achieve well under their own steam.

Steve Sailer summarizes the policy implications well. He says that there is no overall equality or inequality between blacks and whites, only differences, and deplores the Leftist habit of denying that any differences exist:

We must finally take seriously the value of diversity. The first step is to drop the fashionable but Orwellian habit of saying "diversity" when we mean "sameness." To pretend that all groups have all the same talents to all the same degree is the antithesis of truly celebrating diversity.

But do Leftists really believe their claim that the black and white populations are inherently equal intellectually? If so, why is the gross discrimination in favour of blacks that is euphemistically called "affirmative action" seen as necessary? Surely if Leftists saw blacks as genetically equal, all that would be needed would be to ensure that blacks had equal opportunity (equal access to education etc.) to ensure equality of outcomes. Instead, however, Leftists see it as necessary to enforce equal outcomes by the weight of the law. Their deeds reveal that Leftists obviously do NOT really believe that blacks are inherently equal to whites.

This Leftist hypocrisy would also seem to show in the current Leftist doctrine that preferential admission of blacks to universities and colleges is needed to ensure "diversity" on US campuses. No testing of the "diversity" of thinking in the relevant candidates for admission is done. Just their blackness seems to suffice as evidence that they will add "diversity". Their backgrounds could be thoroughly middle class but there is still that unshakable confidence that they will add "diversity". This implies that blacks think differently from whites just because they are black. That may well be true but acting on such a principle seems to betray precisely that belief in inborn racial differences which Leftists normally condemn vehemently in others.

CODA

IQ is just the start of the differences that can be genetically inherited and racially differentiated. Note for instance the way the anti-heredity psychologist Jerome Kagan was dragged kicking and screaming by his own findings into acknowledging inborn personality differences between Han Chinese and white children.


Addendum

The Kane & Brand article mentioned above is now subscriber-only so I reproduce below the passage relevant to S.J. Gould:

Perhaps the most cited critic of g was the late Harvard biologist, Stephen J. Gould. His 1981 text, The Mismeasure of Man, is still widely known for its strident condemnation of g, as well as its personal attacks on many researchers who choose to study a general factor of intelligence.  The book was well received by the general public, winning the National Book Critics Circle award.  In 1996, it was re-issued as a refutation to The Bell Curve (Herrnstein & Murray 1994).

The pivotal argument of The Mismeasure of Man is that researchers investigating individual differences in intelligence have intentionally and misleadingly reified Spearman's g. With immodest effrontery, Gould inaccurately paraphrased many scientists, claiming they view g as a "quantifiable thing" and a "single scaleable, fundamental thing residing in the human brain" (p. 259).  Gould claimed this error of reification resulted in the "hegemony of g" (p. 234) as an instrument of bias and discrimination.  In his own words:

This book is about the abstraction of intelligence as a single entity, its location within the brain, its quantification as one number for each individual and the use of these numbers to rank people in a single series of worthiness, invariably to find that oppressed and disadvantaged groups-races, classes, or sexes-are innately inferior and deserve their status. (p. 25)

However, even a cursory reading of Spearman (1904), Burt (1940), and Jensen (1982) confirms that no expert in the field of factor analysis or intelligence has ever considered g a "thing" to be found in the human body. Fifty years before the first publication of The Mismeasure of Man, Burt (1940) addressed the error of reification in his text, The Factors of the Mind.  From a chapter entitled, "The Metaphysical Status of Mental Factors," Burt warned that "to speak of factors of the mind as if they existed in the same way as, but in addition to, the physical organs and tissues of the body and their properties, is assuredly indefensible and misleading" (p. 218). In a direct response to Gould's misquotations, Jensen (1982) stated:

In the same chapter from which Gould is supposedly paraphrasing my views, I stated unequivocally that intelligence is not an entity, but a theoretical construct.which is intended to explain an observable phenomenon, normally the positive intercorrelations among all mental tests, regardless of their apparently great variety. (p. 126)

Therefore, Gould himself seems to have been the source of the error of reification, rather than Burt, Spearman, or Jensen. The funny thing is that Gould was quite happy to accept other products of factor analysis, the Thurstone-type multiple factors: it was only g that seemed to Gould to involve grievous philosophical error.

A growing body of research suggests that the provenance of g may lie not in factor analysis of mental test items, but in genetic and physical variables and in more "basic" psychological processes.  Kranzler and Jensen (1991) were able to account for 54% of the variance in IQ scores using a battery of reaction time (RT) tasks. Vernon (1990) summarized a number of studies in which measures of g were regressed on subjects' RTs derived from multiple elementary cognitive tasks (ECTs). Various combinations of RT variables accounted for 22% to 56% of the variance in participants' IQ scores. Eysenck and Barrett (1985) found a rank order correlation of 0.93 between the g loadings of the Wechsler Adult Intelligence Scale (WAIS) and the subtests' correlations with a composite measure of the average evoked potential (AEP). Similarly, Haier (1993) reported an average correlation of -0.79 between WAIS subtest performance and glucose metabolic rate (GMR).


* CORRIGENDUM

I referred above to a micrionutrient study conducted in Africa.  I was however rather abbreviated in what I said.  I referred to the  effects of iron supplementation but ignored the iodine issue.  This was because lack of iodine causes cretinism and it seemed obvious to me that no cretin born in Africa would live long enough to complete an IQ test.  Prof. Garza obviously had a similar view