Wednesday, April 11, 2012

Thomas Sowell on IQ and Race

From Thomas Sowell's 1995 review of The Bell Curve.
[Herrnstein and Murray] seem to conclude... that... biological inheritance of IQ... among members of the general society may also explain IQ differences between different racial and ethnic groups.... Such a conclusion goes... much beyond what the facts will support....

[T]he greatest black-white differences are not on the questions which presuppose middle-class vocabulary or experiences, but on abstract questions such as spatial perceptual ability.... [Herrnstein and Murray's] conclusion that this "phenomenon seems peculiarly concentrated in comparisons of ethnic groups" is simply wrong. When European immigrant groups in the United States scored below the national average on mental tests, they scored lowest on the abstract parts of those tests. So did white mountaineer children in the United States tested back in the early 1930s. So did canal boat children in Britain, and so did rural British children compared to their urban counterparts, at a time before Britain had any significant non-white population. So did Gaelic-speaking children as compared to English-speaking children in the Hebrides Islands. This is neither a racial nor an ethnic peculiarity. It is a characteristic found among low-scoring groups of European as well as African ancestry.

In short, groups outside the cultural mainstream of contemporary Western society tend to do their worst on abstract questions, whatever their race might be....

Perhaps the strongest evidence against a genetic basis for intergroup differences in IQ is that the average level of mental test performance has changed very significantly for whole populations over time and, moreover, particular ethnic groups within the population have changed their relative positions during a period when there was very little intermarriage to change the genetic makeup of these groups.

While The Bell Curve cites the work of James R. Flynn, who found substantial increases in mental test performances from one generation to the next in a number of countries around the world, the authors seem not to acknowledge the devastating implications of that finding for the genetic theory of intergroup differences, or for their own reiteration of long-standing claims that the higher fertility of low-IQ groups implies a declining national IQ level. This latter claim is indeed logically consistent with the assumption that genetics is a major factor in interracial differences in IQ scores. But ultimately this too is an empirical issue--and empirical evidence has likewise refuted the claim that IQ test performance would decline over time.

Even before Professor Flynn's studies, mental test results from American soldiers tested in World War II showed that their performances on these tests were higher than the performances of American soldiers in World War I by the equivalent of about 12 IQ points. Perhaps the most dramatic changes were those in the mental test performances of Jews in the United States. The results of World War I mental tests conducted among American soldiers born in Russia--the great majority of whom were Jews--showed such low scores as to cause Carl Brigham, creator of the Scholastic Aptitude Test, to declare that these results "disprove the popular belief that the Jew is highly intelligent." Within a decade, however, Jews in the United States were scoring above the national average on mental tests, and the data in The Bell Curve indicate that they are now far above the national average in IQ.

Strangely, Herrnstein and Murray refer to "folklore" that "Jews and other immigrant groups were thought to be below average in intelligence." It was neither folklore nor anything as subjective as thoughts. It was based on hard data, as hard as any data in The Bell Curve. These groups repeatedly tested below average on the mental tests of the World War I era, both in the army and in civilian life. For Jews, it is clear that later tests showed radically different results--during an era when there was very little intermarriage to change the genetic makeup of American Jews.

My own research of twenty years ago showed that the IQs of both Italian-Americans and Polish-Americans also rose substantially over a period of decades. Unfortunately, there are many statistical problems with these particular data, growing out of the conditions under which they were collected. However, while my data could never be used to compare the IQs of Polish and Italian children, whose IQ scores came from different schools, nevertheless the close similarity of their general patterns of IQ scores rising over time seems indicative--especially since it follows the rising patterns found among Jews and among American soldiers in general between the two world wars, as well as rising IQ scores in other countries around the world.

The implications of such rising patterns of mental test performance is devastating to the central hypothesis of those who have long expressed the same fear as Herrnstein and Murray, that the greater fertility of low-IQ groups would lower the national (and international) IQ over time. The logic of their argument seems so clear and compelling that the opposite empirical result should be considered a refutation of the assumptions behind that logic....

A man who scores 100 on an IQ test today is answering more questions correctly than his grandfather with the same IQ answered two-generations ago, then someone else who answers the same number of questions correctly today as this man's grandfather answered two generations ago may have an IQ of 85.

Herrnstein and Murray openly acknowledge such rises in IQ and christen them "the Flynn effect," in honor of Professor Flynn who discovered it. But they seem not to see how crucially it undermines the case for a genetic explanation of interracial IQ differences. They say:
"The national averages have in fact changed by amounts that are comparable to the fifteen or so IQ points separating blacks and whites in America. To put it another way, on the average, whites today differ from whites, say, two generations ago as much as whites today differ from blacks today. Given their size and speed, the shifts in time necessarily have been due more to changes in the environment than to changes in the genes."
While this open presentation of evidence against the genetic basis of interracial IQ differences is admirable, the failure to draw the logical inference seems puzzling. Blacks today are just as racially different from whites of two generations ago as they are from whites today. Yet the data suggest that the number of questions that blacks answer correctly on IQ tests today is very similar to the number answered correctly by past generations of whites. If race A differs from race B in IQ, and two generations of race A differ from each other by the same amount, where is the logic in suggesting that the IQ differences are even partly racial?

Herrnstein and Murray do not address this question, but instead shift to a discussion of public policy:
"Couldn't the mean of blacks move 15 points as well through environmental changes? There seems no reason why not--but also no reason to believe that white and Asian means can be made to stand still while the Flynn effect works its magic."
But the issue is not solely one of either predicting or controlling the future. It is a question of the validity of the conclusion that differences between genetically different groups are due to those genetic differences, whether in whole or in part. When any factor differs as much from Al to A2 as it does from A2 to B2, why should one conclude that this factor is due to the difference between A in general and B in general?...

A remarkable phenomenon commented on in the Moynihan report of thirty years ago goes unnoticed in The Bell Curve--the prevalence of females among blacks who score high on mental tests. Others who have done studies of high-IQ blacks have found several times as many females as males above the 120 IQ level. Since black males and black females have the same genetic inheritance, this substantial disparity must have some other roots, especially since it is not found in studies of high-IQ individuals in the general society, such as the famous Terman studies, which followed high-IQ children into adulthood and later life. If IQ differences of this magnitude can occur with no genetic difference at all, then it is more than mere speculation to say that some unusual environmental effects must be at work among blacks. However, these environmental effects need not be limited to blacks, for other low-IQ groups of European or other ancestries have likewise tended to have females over-represented among their higher scorers, even though the Terman studies of the general population found no such patterns.

One possibility is that females are more resistant to bad environmental conditions, as some other studies suggest. In any event, large sexual disparities in high-IQ individuals where there are no genetic or socioeconomic differences present a challenge to both the Herrnstein-Murray thesis and most of their critics.

Black males and black females are not the only groups to have significant IQ differences without any genetic differences. Identical twins with significantly different birthweights also have IQ differences, with the heavier twin averaging nearly 9 points higher IQ than the lighter one. This effect is not found where the lighter twin weighs at least six and a half pounds, suggesting that deprivation of nutrition must reach some threshold level before it has a permanent effect on the brain during its crucial early development.

Perhaps the most intellectually troubling aspect of The Bell Curve is the authors' uncritical approach to statistical correlations. One of the first things taught in introductory statistics is that correlation is not causation. It is also one of the first things forgotten, and one of the most widely ignored facts in public policy research. The statistical term "multicollinearity," dealing with spurious correlations, appears only once in this massive book.

Multicollinearity refers to the fact that many variables are highly correlated with one another, so that it is very easy to believe that a certain result comes from variable A, when in fact it is due to variable Z, with which A happens to be correlated. In real life, innumerable factors go together. An example I liked to use in class when teaching economics involved a study showing that economists with only a bachelor's degree had higher incomes than economists with a master's degree and that these in turn had higher incomes than economists with Ph.D.'s. The implication that more education in economics leads to lower incomes would lead me to speculate as to how much money it was costing a student just to be enrolled in my course. In this case, when other variables were taken into account, these spurious correlations disappeared. In many other cases, however, variables such as cultural influences cannot even be quantified, much less have their effects tested statistically....
[emphasis added]
Interesting that Pew Research Center's latest survey on book reading shows blacks (16%) to be slightly less likely than whites (17%) to be non-book readers.

Having lived and taught at college level in a society with a much larger black and mixed race population than in the U.S., the thesis that blacks are less intelligent than whites does not match my experience as a college teacher (anecdotal though it is). Actually what I found was that desire to learn is the key to intelligent learning irrespective of supposed IQ, background or training. Which is why people like St. Peter, John Bunyan and William Carey have a richer, brighter legacy than that of 99.9% of the high IQ population of the last 2000 years.

To give him his due, here's a link to a recent interview with Charles Murray on his latest book Coming Apart.

H/T Peter Robinson


MAX Redline said...

While I don't believe that relative IQ is a function of "race" (indeed, I disagree with the use of the term in general due to its inherent divisiveness), I strongly suspect that factors such as out-of-wedlock birth and the rise of the "single-parent family" figure heavily in the development and ultimate formation of the array of characteristics that taken together define what we term IQ. In the USA, no group has suffered more under policies largely promulgated by Democrats than blacks.

These policies encouraged the bulldozing of entire neighborhoods; supplanting them with Cabrini Greens - as I saw first-hand in Chicago. Marriage and other forms of responsible self-determination were discouraged in favor of patently destructive policies - welfare,ADC, and similar "programs" offer reduced "benefits" to couples, which encourages single-parent families while disincentivizing personal responsibility.

The effort has been wildly successful: today in the USA, 66% of all blacks are single-parent families, compared with 24% of whites and 16% of latinos. In the vast majority of cases, single-parent families consist of a woman and her offspring. The environment is not generally conducive to cognitive development, and therefore has been widely glorified by Leftists - consider the heat that vice-President Dan Quayle received when he criticized the Murphy Brown television character's "decision" to have a child out of wedlock. Democratics had a field day with that.

Democratics, who brought us the wonders of segregation and the Jim Crow laws, have been at once remarkably successful in their continued efforts to marginalize people with black skins, and at portraying Republicans as evil, greedy racists - a caricature that carries through to this day, as Tea Party identifiers are cast as racist "teabaggers" and other forms of deviance.

In general, I find that Democratics aren't especially intelligent, but they are especially crafty. Their world revolves not around logic, not around thought, and most definitely not around fact - instead, their focus is upon emotion, manipulation, and deception. This is why they declare that Republicans are engaged in a "War on Women", even as they tear down the Palins, the Bachmanns, and most recently, the Ann Romneys in this country. It's why they are the first to scream "racist", though their actions clearly demonstrate that it is they who seek to disempower others.

And it is they who refer to a successful black (such as a Supreme Court Justice) as an "Uncle Tom".

T. D. said...

Excellent comment, Max. I would only disagree at one point. Democrats are intelligent but that does not mean wise.

The intelligentsia leans left by a large margin (and they do brutalize any among their own who stray from the party line). A recent Pew poll shows 55% of American college graduates favor the Democratic party and just 31% favor the Republican party. That's a 24 point difference. Those with some college have a 7 point difference and those with high school or less a 10 point difference in favoring Dems over Repubs.

I think that being in the minority and under attack (whether for political or religious reasons) forces people to use their mental abilities more than people who can coast because they have the majority view and, so to speak, the wind behind their back. That's why conservatives usually have better arguments than liberals. They need real arguments since the presumption is against them. Those on the left can often get by with mere laughing or sneering.

In general, I think IQ score is a somewhat useless measurement except for people who have severe learning disabilities. Even then, as in sports when people with real handicaps become champions (e.g., Roger Bannister, Elaine Zayak) desire is primary.

MAX Redline said...

Oh, I'm not saying that Democrats are stupid by any means, T.D. - however, I differentiate between intelligence (which is a rare commodity among the Left) and craftiness (which they possess in abundance).

As a general rule, academia does not foster intellect, but conformity. It is for this reason that some of the most successful Americans (Steve Jobs, etc.) were college dropouts. Having worked in academia, I'm well-acquainted with the pressure for conformity. When working with Dr. L.E.L Rasmussen, for example, on the neurochemistry of the flehmen behavior in elephants, the paper for SCIENCE was initially rejected because the "peer" reviewers knew that elephants exhibit no such behavior. They knew it.

After considerable back-and-forth, I suggested that the wording be altered slightly to "flehmen-like behavior. The paper was subsequently accepted, and the occurrence of flehmen in elephants is now accepted.

I encountered similar resistance when coauthoring other papers for publication in "peer-reviewed" journals, leading me to conclude that academics are generally strongly biased against new material that conflicts with their established beliefs; in other words, they place great value upon conformity.

As this is a hallmark in academia, and as Leftism is strongly reinforced in those settings, it is not only possible, but indeed likely that graduates will exhibit conformity to Leftist precepts. This does not promote intellectual growth, but it's really quite an effective incubator for craftiness. Thus, intellect isn't required for them to prevail; crafty manipulation (often coupled with derision) will suffice.

Of course, there are exceptions; some survive the indoctrination process relatively intact, though as you note, desire is the primary driver (e.g., Temple Grandin, Stephen Hawking, etc.).

T. D. said...

"however, I differentiate between intelligence (which is a rare commodity among the Left) and craftiness (which they possess in abundance)."

Good differentiation, Max. Use of intelligence is different than craftiness (knowing how to use available tools).

The best is to combine the two as you did in getting the article published. The content was intelligent, the phrasing was good use of available tools.

Thanks for both of these thoughtful comments.

MAX Redline said...

Give me a good post to work with, as you so regularly do, and I stick in my 2 cents....

T. D. said...

Thanks, Max. :-)

Unknown said...

It's amazing how utterly uninformed IQ-race critics are. The race differences have been shown, now a number of times, to be qualitatively different from the secular differences. This point was made in the BC and has since been confirmed a number of times: there is neither a theoretical nor an empirical connection between the two phenomena. To summarize the findings: (1) The race differences, in the US at least, are measurement invariant, unlike the secular differences:

"This clearly contrasts with our current findings on the Flynn effect. It appears therefore that the nature of the Flynn effect is qualitatively different from the nature of B–W differences in the United States. Each comparison of groups should be investigated separately. IQ gaps between cohorts do not teach us anything about IQ gaps between contemporary groups, except that each IQ gap should not be confused with real (i.e., latent) differences in intelligence. Only after a proper analysis of measurement invariance of these IQ gaps is conducted can anything be concluded concerning true differences between groups. (
Wicherts, Dolan, Hessen, et al. 2004. Are intelligence tests measurement invariant over time? Investigating the nature of the Flynn effect)"

(2) The race differences are general factor loaded, unlike the secular differences:

"Flynn effect gains are predominantly driven by environmental factors. Might these factors also be responsible for group differences in intelligence? Group differences in intelligence have been clearly shown to strongly correlate with g loadings. The empirical studies on whether the pattern of Flynn effect gains is the same as the pattern of group differences yield conflicting findings. We present new evidence on the topic using a number of datasets from the US and the Netherlands. Score gains and g loadings showed a small negative average correlation. The general picture is now that there is a small, negative correlation between g loadings and Flynn effect gains. It appears that the Flynn effect and group differences have different causes (te Nijenhuis, 2012. The Flynn effect, group differences, and g loadings).

(3) When factor analyzed, the race differences load with biological differences, unlike the secular differences, which load with cultural differences.

(4) As expected from the above, no interaction has been found between the secular rise, in the US, and between race/ethnic differences:

"These prior findings suggest that the NLSYC data can be used as a natural laboratory to study more subtle FE patterns within various demographic subgroups. We test for subgroup Flynn Effect differences by gender, race/ethnicity, maternal education, household income, and urbanization. No subgroups differences emerged for three demographic categories. (Ang et al., 2009. The Flynn Effect within subgroups in the U.S.: Gender, race, income, education, and urbanization differences in the NLSY-Children data.)

In short, there are good reasons for supposing that the cause of the race differences is other than the cause of the secular differences. Even if we didn't know that the race differences were unrelated to the secular differences, of course, Sowell's conclusion would still not follow. The secular rise can no more be an argument against a hypothesis of genetic group differences than it can be against a hypothesis of genetic individual differences. And we know for certain that differences between individuals
within groups are highly genetically conditioned.

The secular rise is a clean illustration of how an IQ score gap need not represent a latent ability gap and how a latent ability gap between populations need not have the same cause as latent ability gaps within populations. But that's all. It's not an argument against genetic differences. It's merely an illustration of how some group differences could be non-genetic, despite interindividual differences being otherwise.

Unknown said...

"While I don't believe that relative IQ is a function of "race" (indeed, I disagree with the use of the term in general due to its inherent divisiveness)...."

Between race differences can be a function of genes without being a function of "race" in the evolutionary sense. For example, in a recent defense of "environmentalism," several prominent authors argued:

"The differences in achievement between Asian Ame icans and White Americans are not hard to explain on cultural grounds. East Asians are members of cultures having a Confucian background.... Matters in the United States have changed since the passage of immigration laws in the late 1960s that encouraged the immigration of highly skilled workers. That change resulted in a huge inflow of talented East and South Asians. These people bring on average very substantial educational and cultural capital and undoubtedly some genetic advantage over the general U.S. population. (Nisbett et al., 2012)."

As they point out towards the end, migrant populations are not necessarily genetically representative of indigenous populations. Differences can arise due to differential migrant selectivity. When it comes to the Black-White gap, in the US, proponents of genetic equality, with respect to psychometric intelligence, are effectively arguing that there are no genetic differences between indigenous populations (e.g., White Europeans and Black West Africans) and that the migrant populations (e.g., European and African Americans) faced similar selective pressures. As for the latter, this might be the case. But I see no a priori reason for supposing it so.