Debunking Nesbit.

Below, I have an article from the Deccan Heights journal. Upon reading it, a reasonably intelligent person would come to the conclusion that nurture has won, 100%, and genetics has very little do with the average human IQ. The article itself is in italics, my comments on each point are in normal type in between.

Contrary to popular belief, recent research has underlined the fact that race differences in IQ are environmental in origin and not genetic.

I’ve noticed this is becoming a common tactic in many areas where scientists disagree. They simply claim victory, even when there’s absolutely no agreement within the community at all. This then gets widely printed, and becomes the ‘default paradigm’, that an overwhelming burden of proof has to be supplied to be shifted, as the media has now effectively sided with the first person to claim that ‘everyone agrees I am right’.  This is seen in the race debate. In spite of the majority of relevant professors (biology, etc) siding with ‘race is real’, because such a fuss was made early on in the middle class media by a few who claimed it was proved to be ‘a social constuct’, everyone now believes that’s what physical anthropologists and geneticists agree on.

There’s quite a bit of research to show the gap is unfortunately genetic.

James Watson, the 1962 Nobel laureate, recently asserted that he was ‘inherently gloomy about the prospect of Africa’ and its citizens 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.’Watson’s remarks created a huge stir because they implied that blacks were genetically inferior to whites, and the controversy resulted in his resignation as chancellor of Cold Spring Harbor Laboratory. But, was he right? Is there a genetic difference between blacks and whites that condemns blacks in perpetuity to be less intelligent?

The first notable public airing of the scientific question came in a 1969 article in The Harvard Educational Review by Arthur Jensen, a psychologist at the University of California, Berkeley. Jensen maintained that a 15-point difference in IQ between blacks and whites was mostly due to a genetic difference between the races that could never be erased. But his argument gave a misleading account of the evidence. And others who later made the same argument – Richard Herrnstein and Charles Murray in ‘The Bell Curve,’ in 1994, for example, and just recently, William Saletan in a series of articles on Slate – have made the same mistake.In fact, the evidence heavily favours the view that race differences in IQ are environmental in origin, not genetic.The hereditarians begin with the assertion that 60 per cent to 80 per cent of variation in IQ is genetically determined. However, most estimates of heritability have been based almost exclusively on studies of middle-class groups. For the poor, a group that includes a substantial proportion of minorities, heritability of IQ is very low, in the range of 10 per cent to 20 per cent, according to recent research by Eric Turkheimer at the University of Virginia. This means that for the poor, improvements in environment have great potential to bring about increases in IQ.70% is the given average, 30% environment. Environment does play a role, absolutely. Mostly, decent nutrition is the number one factor. According to research done on the Flynn effect, average IQ’s in the West have gone up by thirty points, but have now ceased to rise. Most of the increase was seen at the bottom part of the IQ range, as welfare stopped the children of the poor starving, and provided them with passably good health care. Also, the herditability of IQ increases as you age, so all studies based on young children are basically pointless. Dr Turkheimer and I agree that genetics set your upper IQ limit, and the environment dictates how close you will get to that.In any case, the degree of heritability of a characteristic tells us nothing about how much the environment can affect it. Even when a trait is highly heritable (think of the height of corn plants), modifiability can also be great (think of the difference growing conditions can make).

True. But this a reference to a study on children. At 7 years old the heritability for middle class kids isn’t that high either, about 30% at that age. The heritability of IQ increases with age, to about 70% in adulthood.

Nearly all the evidence suggesting a genetic basis for the IQ differential is indirect. There is, for example, the evidence that brain size is correlated with intelligence, and that blacks have smaller brains than whites. But the brain size difference between men and women is substantially greater than that between blacks and whites, yet men and women score the same, on average, on IQ tests. Likewise, a group of people in a community in Ecuador have a genetic anomaly that produces extremely small head sizes – and hence brain sizes. Yet their intelligence is as high as that of their unaffected relatives.

The first real deception. It’s brain size relative to non-fat body mass that is important. Otherwise the blue whale would be building spaceships. And you’d lose IQ points every time you gained a few pounds. What the author of the article also fails to mention is that these small headed Ecuadorians all suffer from dwarfism, so there is no mentionable difference in relative brain size between them and anyone else. It’s called Laron’s syndrome. Strange that it’s perfectly acceptable to look at ancient hominid skulls and say, ‘he was less intelligent, because his brain is half the size’, but not okay to think that this might be in some way relevant to modern humans. He’s also avoided mentioning that blacks have a slightly smaller brain (relatively) than whites, and East Asians have relatively bigger brains, something shown by a mass of research. There have been MRI studies giving an accurate measure of living brain size that show a o.4 correlation (pretty high) with IQ scores.

Why rely on such misleading and indirect findings when we have much more direct evidence about the basis for the IQ gap? About 25 per cent of the genes in the American black population are European, meaning that the genes of any individual can range from 100 per cent African to mostly European. If European intelligence genes are superior, then blacks who have relatively more European genes ought to have higher IQ’s than those who have more African genes. But it turns out that skin colour and ‘negroidness’ of features – both measures of the degree of a black person’s European ancestry – are only weakly associated with IQ (even though we might well expect a moderately high association due to the social advantages of such features).

I can’t find this study. I’ll have another look though. Generally in this field, if the study isn’t being trumpeted around it means it won’t stand up well to close scrutiny.

It’s a slightly misleading paragraph. The degree of admixture varies from area to area in America. A lot of the 50% black people won’t look particularly African. Also, IQ is very strongly matched in spouses, a process called assortive mating. The IQ of spouses is usually very close. So a high IQ black (mostly African ancestry) person is more likely to find a mate with the same IQ range in the white or black community, their kids won’t be smart because of  European ancestry. Like marries like. I doubt mixed ancestry has made any real difference to the black American IQ. The mixed race kids in the IQ studies probably had an intermediate score because that’s were most of the overlap between black and white IQs occurs.  

During World War II, both black and white American soldiers fathered children with German women. Thus some of these children had 100 per cent European heritage and some had substantial African heritage. Tested in later childhood, the German children of the white fathers were found to have an average IQ of 97, and those of the black fathers had an average of 96.5, a trivial difference.

Nesbitt doesn’t mention that lower IQ black soldiers were filtered out by the armies testing procedures. I believe the minimum was an IQ of 85 or 89. This would have meant the average black soldier would have had a higher IQ than an average black man on the street. In the nineties, I worked out. Also, it’s been shown that mixed race children with a white mother have a higher IQ than if they had a black mother. While this has been taken by some to mean that nurture has a significant impact, it could very well be that the extra week of gestation in white women makes some difference to the child’s IQ (no, I didn’t make that up), and it’s entirely possible that some genes controlling intelligence are inherited only from one parent, or are expressed differently if inherited from male and female (look up ‘happy puppet’ syndrome, this is also possible). Also, the author completely overlooks that fact that there was real racism in Germany at that time, and for a white woman from recently Nazi Germany to be having sex with a black man, he would have to have something to offer, in resources or some kind of status. Like being an officer, or able to get his hands on food, things that need some smarts.

If European genes conferred an advantage, we would expect that the smartest blacks would have substantial European heritage. But when a group of investigators sought out the very brightest black children in the Chicago school system and asked them about the race of their parents and grandparents, these children were found to have no greater degree of European ancestry than blacks in the population at large.

See former point about assortive mating an IQ. Also, he doesn’t mention these children’s IQs. And, no-one ever said that there are no intelligent 100% African people. That the average is different, does not mean that they don’t range all the way from Forest Gump to Einstein.

Most tellingly, blood-typing tests have been used to assess the degree to which black individuals have European genes. The blood group assays show no association between degree of European heritage and IQ. Similarly, the blood groups most closely associated with high intellectual performance among blacks are no more European in origin than other blood groups.

I admit this is a new one to me, and I can’t find a reference to it anywhere. But also, assortive mating. I don’t believe European DNA has made any real difference to the African American gene pool for IQ. Possibly a lot of the smartest black people in the past ‘married white’, and having their best brains being cherry picked out repeatedly may have contributed to the problem.  Given the overt racism in American, I don’t think it’s likely to have been the unsuccessful,  low IQ black people that married white partners.

The closest thing to direct evidence that the hereditarians have is a study from the 1970s showing that black children who had been adopted by white parents had lower IQs than those of mixed-race children adopted by white parents. But, as the researchers acknowledged, the study had many flaws; for instance, the black children had been adopted at a substantially later age than the mixed-race children, and later age at adoption is associated with lower IQ.

Actually true. You have to be adopted before six months to get the full IQ benefit of adoptive parents. It’s quite likely to do with nutrition, but could be other. It’s possible that stimulation  and decent nutrition in early infancy encourages  better post natal ‘neural wiring’. Again though, it’s a study on children, soooo….

A superior adoption study – and one not discussed by the hereditarians – was carried out at Arizona State University by psychologist Elsie Moore, who looked at black and mixed-race children adopted by middle-class families, either black or white, and found no difference in IQ between the black and mixed-race children. Most telling is Moore’s finding that children adopted by white families had IQs 13 points higher than those of children adopted by black families. The environments that even middle-class black children grow up in are not as favourable for the development of IQ as those of middle-class whites.

Apart from there being less than fifty children in this study… This was a study on children age 7 and 10. Always, studies that show nurture as the winner never follow children into adulthood. When children leave home, their IQ rises or falls to be more like their birth parents. It is also possible for good parents to push a child’s development forward with a good environment and tuition, although this doesn’t make a difference in the long run to IQ scores. It’s also well known that black children mature physically and mentally slightly faster, so childhood studies on IQ are all absolutely worthless. You need to track down adults and test them. Studies on ‘virtual’ twins (nothing to do with any racial study), children adopted and grown up together, showed that adult IQ’s have no more relationship to each other than the IQ’s of total strangers. They did bear a good relationship to the IQ of their birth parents, however. Score one for nature.

Important recent psychological research helps to pinpoint just what factors shape differences in IQ scores. Joseph Fagan of Case Western Reserve University and Cynthia Holland of Cuyahoga Community College tested blacks and whites on their knowledge of, and their ability to learn and reason with, words and concepts. The whites had substantially more knowledge of the various words and concepts, but when participants were tested on their ability to learn new words, either from dictionary definitions or by learning their meaning in context, the blacks did just as well as the whites.

Not exactly the same as IQ. And who were the people tested? They were all students from the same community college, not a random sampling. They would all have had a similar level of intelligence.

Whites showed better comprehension of sayings, better ability to recognise similarities and better facility with analogies – when solutions required knowledge of words and concepts that were more likely to be known to whites than to blacks. But when these kinds of reasoning were tested with words and concepts known equally well to blacks and whites, there were no differences. Within each race, prior knowledge predicted learning and reasoning, but between the races it was prior knowledge only that differed. What do we know about the effects of environment?

That environment can markedly influence IQ is demonstrated by the so-called Flynn Effect. James Flynn, a philosopher and IQ researcher in New Zealand, has established that in the Western world as a whole, IQ increased markedly from 1947 to 2002. In the United States alone, it went up by 18 points. Our genes could not have changed enough over such a brief period to account for the shift; it must have been the result of powerful social factors. And if such factors could produce changes over time for the population as a whole, they could also produce big differences between subpopulations at any given time.

In fact, we know that the IQ difference between black and white 12-year-olds has dropped to 9.5 points from 15 points in the last 30 years – a period that was more favourable for blacks in many ways than the preceding era. Black progress on the National Assessment of Educational Progress shows equivalent gains. Reading and math improvement has been modest for whites but substantial for blacks.

Untrue. There are two different ways of working out the mean IQ. The accurate one (Murray), which only uses people of the same age (cohort), showed no closing of the IQ gap.

Most important, we know that interventions at every age from infancy to college can reduce racial gaps in both IQ and academic achievement, sometimes by substantial amounts in surprisingly little time. This mutability is further evidence that the IQ difference has environmental, not genetic, causes. And it should encourage us, as a society, to see that all children receive ample opportunity to develop their minds.

All the ‘interventions’ I’ve read through only produced temporary results, and were essentially pointless. The author never mentions that Mongoloid people routinely score higher than Europeans, and is very careful to couch the whole item in terms of white-oppressing-black. Whereas, impoverished peasants in East Asia routinely score better than well off black Americans. And average white Americans. Very selective and misleading. The phrase ‘smoke and mirrors’ springs to mind.

I’d just like to add, that from an evolutionary view point, there is absolutely no reason for one population to be homogeneous with another for anything. Selective pressure due to different environments, and new mutations, will make groups vary in what they excel at. At the moment, most of the selective pressure in Africa seems to be to survive malaria, or to reproduce fast enough to make up for the obscenely high child mortality rate from malaria. Everything else has had to take second place.

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1 Comment

Filed under IQ, race

One response to “Debunking Nesbit.

  1. keypusher

    You can check out the papers gathered here. http://www.slate.com/id/2178122/entry/2178124/, in particular Jensen and Rushton’s lead article, Nesbitt’s critical paper, and Jensen and Rushton’s rebuttal.

    The study Nesbitt cited for high-IQ black children not having European ancestry was conducted in Chicago on 63 children in 1936, based on self-identification. The blood-group studies were conducted in the 1970s. Obviously studies based on self-identification and blood groups are obsolete: now we can conduct highly accurate studies, if we want, using DNA analysis. The adoption studies are also discussed in the articles cited in my first pareagraph above.

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