(See previous columns in this series.)
Myths about group differences in IQ and behavior depend very much on myths about individual differences in IQ and behavior. For example, some untenable ideas about the heritability of IQ are a central component of hereditarian explanations of group differences. Because of this overlap, discussion of myths about group differences often needs to include consideration of individual differences. In this column I focus on IQ and behavior myths with a special emphasis on myths related to race or groups as a whole and to cultural factors.
Myth: Biological or genetic determinism is a nothing more than a scientific discipline that studies the biological basis of all forms of human behavior.
Reality: Biological or genetic determinism as applied to human behavior is an ideology rather than a scientific discipline. It proposes that humans differ in fundamental abilities because of innate differences, that these innate differences are biologically inherited, and that human nature guarantees the formation of a hierarchical society -- top dogs and bottom dogs.
Myth: Intelligence is a general mental capability that involves the ability to reason, plan, solve problems, think abstractly, comprehend complex ideas, learn quickly, and learn from experience -- a broad and deep capability for comprehending our surroundings. Intelligence so defined can be measured, and intelligence tests measure it well.
Reality: The deep fallacy is the idea that any concept occurring in the human mind and expressible in language is a real measurable entity. Apart from measuring learning rates (for example, "learning quickly"), nothing in this myth can be measured quantitatively and reliably with objective measuring instruments. Intelligence is a concept, not an object or a succinct event, and no more measurable than beauty, truth, wisdom, humor, misery, and so on. What we can measure quantitatively is cognitive performance on a certain task. The only meaningful definition of cognitive performance is operational and in terms of the instruments used to measure it.
Myth: Different types of intelligence tests all measure the same intelligence.
Reality: This is a fallacy. Since cognitive performance is defined operationally, the definition must change as the test changes. The myth is based on the pair correlations between scores on one type of test with scores on another type of test. But pair correlations measure only similarities of variation and imply nothing about underlying causalities. There is no basis for the idea that pair correlations between two sets of test scores indicate the tests are measuring the same variable.
Myth: The spread of people along the IQ-test continuum, from low to high, can be represented by the bell curve (the normal curve).
Reality: The questions in the IQ test are designed to produce a bell-curve distribution of scores. It's possible to design a cognitive performance test that produces another kind of distribution. What we find as the "spread of people" in cognitive performance depends on the measuring instrument we use.
Myth: Intelligence tests are not culturally biased against American blacks or other native-born English-speaking people in the United States. Culture bias in IQ tests does not explain the difference in black-white IQ scores, a difference of approximately 15 points between the means of group distributions.
Reality: The idea that all "native-born English-speaking people in the United States" develop and live in the same culture is anthropological nonsense. Cognitive performance is never independent of culture any more than the way language is used is independent of culture. Linguistic structure, in fact, controls the way people think and learn, so that if linguistic structure is culture dependent, so also is thinking and learning. As for cultural bias in IQ tests not explaining the difference in black-white IQ scores, there is no hard scientific evidence to support any such idea -- and considerable evidence against it. The notorious black-white IQ gap of one standard deviation (about 15 points), touted by genetic determinists to be independent of culture, was in fact substantially reduced between 1972 and 2002 -- and it continues to shrink.
Myth: Heritability is the squared correlation of phenotype with genotype. Heritability estimates for IQ range from 0.4 to 0.8, most estimates thereby indicating that genetics plays a bigger role than does environment in creating IQ differences among individuals.
Reality: If heritability is the squared correlation of phenotype with genotype, the assumption is that the phenotype and genotype under discussion can be measured. The human individual genotype is not yet even defined, let alone measurable, so with or without a measurable phenotype, "heritability" cannot be calculated without restrictive assumptions. As for the range of 0.4 to 0.8 for the heritability of IQ, it's a fallacy based on an assumption of independent genetic and environmental variables in a linear relationship with heritability, which means no gene-environment interactions. The deep fallacy is that any contributions to variance due to factors acting before birth (such as prenatal impacts) are assumed to be genetic. As far as genes playing "a bigger role" than environment in creating individual differences in IQ is concerned, that's a total misreading of the meaning of a correlation coefficient.
Myth: Although the environment is important in creating IQ differences, we do not know yet how to manipulate it to raise IQ permanently.
Reality: Most evidence suggests the opposite. For example, concerning prenatal impacts, the known effects on fetal brain development and later IQ of factors such as environmental pollution, maternal stress during gestation, and poor health care for pregnant women imply that removing these stressors would ultimately mean an improvement in postnatal IQ.
Myth: To the extent that genes play a role in intelligence, IQ will vary by racial admixture.
Reality: This simplistic statement is not true. Given the complexity of gene expression prenatally and postnatally, variation by racial or ethnic admixture may or may not occur. There is certainly no scientific evidence to support the myth, and racial admixture blood group analysis does not predict IQ. Human intelligence, whatever it is, is certainly not a Mendelian trait.
Myth: IQ subtests based on abstract designs have little or no cultural content.
Reality: The fallacy here is the assumption that cultural bias means only culture-dependent content. Methods of problem solution can also be culture dependent. If the method that must be used to solve an abstract problem is common to one culture but not to another culture, the problem is culturally biased.
Myth: the Spearman g-factor (also called "global intelligence" or "general intelligence") represents a biologically grounded and highly heritable cognitive resource, which gives one reason to think that not much about black-white IQ differences will change in the years to come.
Reality: The so-called biological grounding consists of correlations with various physiological parameters such as brain evoked potentials, brain pH levels, brain glucose metabolism, peripheral nerve conduction velocity, and psychological reaction time. All of these are also correlated with nearly everything that goes on in the brain, and none of these parameters has ever been established as a determinant of cognitive performance. The g correlations are merely evidence that the brain is a part of the body involved in taking an IQ test. The correlations tell us nothing about any "biological grounding" or any causal relation between any physiological variable and IQ scores. As expected, neuroscientists are not at all excited about Spearman's g-factor. It tells them nothing about the neurological substrate of cognitive performance. Concerning the "high heritability" of g, as I have pointed out, the numerical value assumes a fallacious linear statistical model and a fallacious biological model that lumps all prenatal environmental impacts with the genotype variance. As for the idea that not much about black-white differences in IQ scores will change in the years to come, there is no scientific evidence to confirm that idea, and there are hundreds of studies that suggest otherwise. The black-white IQ score distributions are now less than one standard deviation apart, and "the years to come" may demonstrate that elimination of prenatal impacts that are damaging to the brain and often transgenerational may also eliminate black-white group differences in IQ scores. There is certainly no evidence to suggest the idea that differences are intractable. A high calculated "heritability" says nothing about the possibility of future change. It's an old reality that a trait can have a current heritability of 1.0 (which means 100 percent of total variance is due to genetic variance) in a population and be completely altered in the future by a new environment that introduces environmental contributions to variance.
Myth: Genetic cluster analysis of DNA supports the common notion of individual "races" among modern peoples.
Reality: Genetic cluster analysis of DNA supports the idea of DNA clusters -- and that's all. Relating these clusters to so-called races is problematic. For example, DNA analysis reports a non-black Hispanic-American cluster different from a "white" cluster, but Hispanic-Americans are not commonly viewed as a "race" by most Americans. In addition, there is no evidence from any cluster analysis that the DNA components related to clustering are involved with intelligence or behavior. It's possible the DNA components that produce clustering are all related to superficial phenotype traits such as skin color, eye color, and so on.
Myth: The correlation between brain size and intelligence within either race, and the average difference in brain size and intelligence between blacks and whites, are well established in the scientific literature.
Reality: This canard is a common argument of white supremacists, but the scientific literature does not support the idea. What the scientific literature does suggest is a relation between cognitive performance and the thickness (or thinness) of certain regions of the cerebral cortex, but there are no reliable data measuring cortical thickness differences between ethnic groups.
Myth: Because prenatal effects are more or less random, they are difficult to remedy or control, and their occurrence has probably been reduced in recent decades by improved maternal nutrition, advances in obstetrical techniques, and improved health in general.
Reality: First, prenatal effects are not "more or less random" but usually nonrandom effects due to environmental pollution or cultural impacts on maternal psychology or physiology. Second, the variety of prenatal effects is so broad there is no basis for the statement that they are "difficult to remedy or control" --indeed, some prenatal impacts (for example, tobacco smoking and alcohol use during pregnancy, nutrition and infection, etc.) are relatively easy to control. Third, there is no evidence at all that prenatal impacts have been reduced in recent decades to make them now of little or no importance.
So much for some myths and realities. It's unfortunate that too many people who ought to know better are so eager to promote the idea of intellectual differences between blacks and whites in America. Their eagerness continues to appear as a psychiatric puzzle, the old tribal hoax covered by transparent veils.
Humans are a complex species with plastic brains that allow rapid behavioral changes from one generation to the next through cultural evolution. Brain plasticity means our brains can be wired and rewired by experience. No other species has any comparable biological capability -- not to the degree present in humans. As for black and white in America, it would certainly help us all to focus more on our similarities than on our differences. Meanwhile, until White America stops standing on the face of Black America, let's not delude ourselves that we're free of the tribal hoax.
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Here are a few books (one to be published soon) that expand on some of the ideas presented in this series of columns:
Agin, D. Changing Destiny: How the Fetal Environment Shapes IQ and Behavior. Oxford University Press, 2009 (in press).
Gould, S. The Mismeasure of Man. W. W. Norton, 1996.
Graves, J. The Emperor's New Clothes: Biological Theories of Race at the Millennium. Rutgers University Press, 2002.
Jencks, C. and Phillips, M. (Eds.) The Black-White Test Score Gap. Brookings Institution Press, 1998.
Kevles, D. In the Name of Eugenics: Genetics and the Uses of Human Heredity. Harvard University Press, 1995.
Lewontin, R., Rose, S., and Kamin, L. Not In Our Genes: Biology, Ideology, and Human Nature. Pantheon, 1984.
Tucker, W. The Science and Politics of Racial Research. University of Illinois Press, 1994.
Not true. Binet developed the test to identify which students needed special assistance. The tests have strong predictive value in terms of academic performance, and occupational ability (particularly for more complex jobs). This is one of the reasons the army continues to use them.
But how do you explain the adoption studies which point away from a culture explanation? For instance, East Asians raised in white households still, on average, do better on psychometric tests. Asian children adopted by white families mature to have IQs that are consistent with their biological peers and which are higher than their adoptive parents. http://www.gnxp.com/MT2/archives/004064.html
[1] Clark, E. A., & Hanisee, J. (1982). Intellectual and adaptive
performance of Asian children in adoptive American settings.
Developmental Psychology, 18, 595–599.
Frydman, M., & Lynn, R. (1989). The intelligence of Korean children
adopted in Belgium. Personality and Individual Differences, 12, 1323–1325.
Winick, M., Meyer, K. K., & Harris, R. C. (1975). Malnutrition and
environmental enrichment by early adoption. Science, 190, 1173–1175.
Also, see the paper by Cochran, Hardy & Harpending, "Natural History of Ashkenazi Intelligence, Journal of Biosocial Science 38 (5), pp. 659–693 (2006). http://homepage.mac.com/harpend/.Public/AshkenaziIQ.jbiosocsci.pdf
Finally, you cite 'The Mismeasure of Man' which was popular in the media the reviews in the scientific journals were almost all highly critical (Davis, Bernard D. (1983). Neo-Lysenkoism, IQ, and the press. The Public Interest, 74, 41-59).
http://www.debunker.com/texts/jensen.html
"Underlying all the varied detail of Gould's exposition is a philosophy of science, or rather a sociology of science, which emphasizes the notion that scientific endeavor generally is not so much a search for objective knowledge as it is a sociopolitical activity, reflecting the social context and value systems within which individual scientists do their work. According to this view, socially conditioned presuppositions or prior prejudices about the nature of society force even "good scientists" to produce theories and conclusions that inevitably confirm their own social prejudices and lend to them additional support in the guise of scientific truth."
Interview with Gregory Cochran, co-author of the book The 10,000 Year Explosion.
http://www.2blowhards.com/archives/2009/01/a_week_with_gre_1.html#005818
2B: "One implication would seem to be that there are striking differences between populations that developed agriculture long ago and ones that encountered it only recently. Fair?"
GC: "Yes. Peoples with short histories of agriculture have trouble with alcoholism, diabetes, and generally have a lot of trouble fitting into complex hierarchical societies."
2B: Because we create our own culture, and do so at least semi-consciously, this would all seem to imply that we have -- if only to a microscopic extent -- some semi-conscious influence over how we evolve. To what extent is that a fair or not-fair thing to say or think?
GC: I would say that many human genetic changes have been the result of culture innovations and choices, but it's hard to think of a change that anyone planned or intended.
As the author says, up to now the impact of culture on our evolution has been unintended, but we are now at the point where it can be. Why should we not take an active role in how our species evolves? If we can rid ourselves of disease or lengthen life by altering our DNA, why shouldn't we? Similarly, if we can make ourselves smarter and more empathic by manipulating genes and the fetal and post-fetal environment, why shouldn't we? Presumably, even the Blank Slaters don't have a problem altering the human genome for disease prevention purposes. Correct Professor Agin?
Because:
1) We currently do not understand very well specifically how allelic variants interact with other genes and developmental factors to give rise to differences in empathy and intelligence.
2) We should not experiment on human beings - since manipulated embryos will be born to become children and adults. Such experiments will inevitably produce defects before "success" is achieved.
3) We do not have the right to decide for future generations what their nature should be. (An argument made by CS Lewis in The Abolition of Man.)
Curing life-endangering and severely handicapping genetic diseases is another matter.
Note: I do not agree with Cochran and Harpending's racialist thesis. They have very little evidence to support their speculations on genetic differences in potential for intelligence and temperament between races.
2B: What are some of the other cultural developments that might rank, if not entirely up there with agriculture, almost up there? And how might they or would they have influenced human evolution?
GC: The development of strong states probably limited local violence and thus upped the selective importance of food shortages and infectious diseases. In the past, good government, absent of rapid technological change, led to lower living standards.
The Ashkenazi Jews couldn't have gone down the path they did before the invention of writing and currency. You can think of them as a scribe caste. I can imagine a situation in which something similar happened in the past, well before the Ashkenazi Jews -- an enduring, reproductively closed caste of priests with strong selection for verbal intelligence. This could have happened in Egypt: if it had, selection could have operated for much longer than among the Ashkenazim, with more dramatic effects. Didn't happen, but it would make for an interesting story.
How do the Blank Slaters account for the high cognitive performance of the Ashkenazi Jews?
http://www.eons.com/groups/topic/894197-Obama-s-IQ-The-Highest-Of-Any-President-Ever-
Intelligence is "no more measurable than beauty, truth, wisdom, humor, [or] misery?"
My guess is that Obama will be one of the best presidents the country has ever had, and I cannot shake the belief that his IQ will play a principal role in his success.
Would we have a better, more competent government if every politician had to meet a minimum IQ requirement (say, 150)?
I would like to read an article about what IQ scores don't predict (like honesty, empathy, etc.--thinking of our last president).
John McCain: 133
Sarah Palin: "at least 125" (who believes this one?)
Rudy Giuliani: 123
Duncan Hunter: 120-130
Ron Paul: 130-140
Mitt Romney: 122
Fred Thompson: 123
http://www.kids-iq-tests.com/r-prez.html
Joe Biden: 135 (est)
Hillary Clinton: 140 (confirmed and validated)
http://www.kids-iq-tests.com/d-prez.html
George W. Bush: 125 (est-based on his SAT score)
Al Gore: 133-134 (confirmed)
http://www.vdare.com/Sailer/kerry_iq_lower.htm
My conclusion: 130 should be a constitutionally mandated minimum IQ requirement for any member of Congress and 150 for president or vice president. There already is an age requirement--which is more important?
Jeff Ogden 23: 133 (Married and no kids. Works for Dell in Austin, Texas)
Mary Baker 36: 138 (Single mom, waitress from Daytona Beach, Florida)
Danny Jones 29: 131 (Pastry Chef, Las Vegas, Nevada)
http://www.kids-iq-tests.com/d-prez.html
Higher scores than most of our politicians. Maybe these people should be in Congress.
http://www.udel.edu/educ/gottfredson/reprints/2005hereditarian-hypothesis.pdf
You misrepresent the other side. No current intelligence researchers argue that environment plays no role in behavior. To the contrary, the "hereditarians" I have read say that behavior is affected by both heredity and environment in equal measure.
Is it unrealistic to hypothesize that biology has something to do with this thing called intelligence (or any other human trait)?
A more interesting line of attack might be the concept of intelligence itself. It is estimated that George W. Bush has an IQ of about 125 (based on his SAT scores). What does that say about "intelligence" as measured by IQ tests?
1) Who said biology has nothing to do with intelligence or other human traits?
2) Concerning your reading, every myth in column IV is out of the mouths of hereditarian psychometricians. The short list of books at the end should be of help to you.
Thanks again for your input.
Would it be a good thing in your view if everyone's IQ could be increased somehow, or is IQ a totally meaningless and useless measure?
However, to argue that such differences are fixed, except in the most loose definition of fixed, being between x minimum and x maximum for a particular exemplar, would be folly. I agree.
Thanks for your reply. I am a fan.
For the most part, I agree with all you say. In fairness, though, I think it is important, either for the sake of argument, or for the sake of scientific objectivity, that you set up fewer straw men, and give a bit more credence to the possibility that differences do exist between humans in terms of cognitive abilities, at least as they are measured by our standard tests. Variability is certain; significant difference by genotype is also possible, and perhaps likely given the effects of environment over the long term.
As variables collapse into homogeneity, as differences in things such as prenatal care become negligible, perhaps we'll have enough information to judge more properly. Until then, however, I think, as distasteful as it may feel, it is important to not dismiss the possibility that there are differences between races or geographically-isolated groups. Even polygenic traits can be considered heritable, if not in a strictly mendelian sense, by any simple matrixes.
By the way; I do not assume that whites are superior. It'd be pretty fitting if we were found to be inferior, after all...
Thanks again. Great series.
We don't all have the potential of becoming an Einstein, Newton, or Chris Langan, do we?
That's the eugenic argument, and it's long been debunked.