A commenter on this blog named “Swanknasty” seems to feel the high IQs of Africans in Britain debunk HBD and apparently feels that it’s the responsibility of HBDers to explain every anomaly that occurs anywhere in the world.  As I discussed in a previous post, in 2009, the kids of African immigrants in Britain had an IQ of about 94 (on national norms); this converts to an IQ of 92 on Richard Lynn’s scale where IQs are calculated only with reference to whites, and Swanknasty has since cited even more recent data (see page 10 of this document) that these kids score the same as British whites on the GCSE, implying an IQ of 100 on Richard Lynn’s scale.  It should be noted that the GCSE  is not an intelligence test, but an education exam, though it correlates about 0.7 with the general intelligence factor (g), a figure substantially lower than the 0.85 g loading of most official IQ tests.  But let’s say the kids of African immigrants have an average IQ anywhere from 92-100.

An IQ of 92-100 is quite high because according to scientist Richard Lynn, sub-Saharan Africa has an average IQ of 67 (genetic IQ 80).  By contrast African Americans who Lynn feels have much better nutrition & living standards, have IQs from 80 to 95 depending on how much white admixture they have, with an average IQ of 85.

So why do the children of African immigrants in Britain (who presumably have little white admixture) have an IQ of 92-100?  The obvious answer is that their parents are highly selected and whatever regression to the African mean occurs in their children is roughly negated by the huge nutrition boost they get from being born in the UK.  Remember that according to Lynn, even African Americans with virtually no white admixture have an IQ of 80, compared to the mean of 67 in sub-Saharan Africa, suggesting first world conditions boost IQ of Third Worlders by 13 points.

But Swanknasty believes I am overestimating both how selected African immigrants to Britain are and how much of a nutrition boost their children get.  So in this post, I will try to bring some new numbers.

How selected are immigrants from Africa?

Swanknasty cited page 18 of this paper to claim that in 1979, first generation African immigrants had a mean of 12.2 years of education.  Swanknasty felt this showed that they are not that highly selected since they are only a little more educated than high school graduates on average, but the African born immigrants surveyed in 1979 were roughly 36 years old and would have likely attended university around 1963.  Figure 1 in this document, shows that in 1970, less than 1% of college age sub-Saharan Africans were enrolled in tertiary education.  Further, in 1950 South Africa, only 0.5% of Africans even qualified for university.  So being a bit more educated than a high school graduate in 1963 likely put African immigrants to Britain in the top 0.5% to top 1% of sub-Saharan Africans of their cohort.  Normalizing the distribution, the African immigrants to Britain are 2.43 standard deviations (+2.43 SD) more educated than the average black African.

Assuming a 0.65 correlation between IQ and education (Jensen, 1998), we would expect their IQs to be 0.65(+2.43 SD) = +1.58 SD higher than the average black African.  Assuming the sub-Saharan distribution has a mean of 67 and an SD of 15, that puts them at 91 (24 points above the African mean).  This is probably a conservative estimate; those who migrate to Britain are not only way more educated than the average African, but were resourceful enough to escape a poor country and adapt to an unimaginably prosperous one.  In addition, many of them, despite being born in Africa, probably achieved their education in the developed world, suggesting they met even higher standards than university students educated in sub-Saharan Africa.

How smart would their kids be?

Now given that the correlation between the IQs of both parents averaged together correlates 0.6 with the IQs of their kids, the children of smart parents are only 60% as far above average as their parents.  So if first generation African immigrants averaged IQ 91 (24 points above the black African mean), their kids should average average 81 (14 points above the black African mean).  So why do they average 92-100?  81 would be the expected IQ of the children if their parents had decided to stay in sub-Saharan Africa.  But as I explained above, Richard Lynn believes the IQs of sub-Saharans are 13 points below their genetic IQ; the IQ they would have had under first world conditions.  These kids were born in first world conditions, so we must add 13 points to their IQ of 81, which raises it to 94.

Of course all this is quite oversimplified.  The full nutrition boost might not happen until the grandchildren of African immigrants since even second generation immigrants can still be born to women who experienced malnutrition in the old country which could harm the nutrition of the fetus.  However elite Africans have been migrating to the UK for multiple generations so multi-generation effects are plausible.

Does migrating from the Third World to the First World really boost IQ by 13 points in the next generations?

As mentioned above, scientist Richard Lynn believes that even African Americans with virtually no white admixture have an average IQ around 80 (13 points above the sub-Saharan mean of 67, according to Lynn).  This implies First World conditions lift IQ by 13 points or just over 0.8 SD.

As brilliant blogger Steve Sailer noted, support for this idea can be seen by comparing First World and Third World heights.  A study recruited peoples of West African ancestry from several places around the world.  The West Africans born in America (who had presumably lived in the developed world for centuries) had a mean height of 1.765 m (SD = 0.073) for men (see table table 1 of this document) and 1.634 m (SD = 0.064 for women).  By contrast, in the exact same study, men living in sub-Saharan countries had a mean of 1.684 m (Nigeria) and 1.701 m (Cameroon), so about 1.693 m overall; women in sub-Saharan countries had a mean of 1.583 m (Nigeria) and 1.607 m (Cameroon), so about 1.595 m overall.

In other words, Third World West African men were 0.99 SD shorter than African American men, and Third World West African women were 0.61 SD shorter than African American women; averaging across both genders, it seems being born in Africa stunts height by about 0.8 SD, relative to those born in the First World.  If First World conditions are powerful enough to lift height by 0.8 SD, why can’t they do the same for IQ?  Height is even more heritable and less malleable than IQ is, so if it works for height, it can work for IQ.  As Lynn has noted, this is likely also the major cause of the Flynn effect,  since even in the developed world, heights have increased substantially over the 20th century.  It also likely explains why the children of highly selected Indian immigrants to America (who enjoy far better nutrition than they would have India) do not seem to regress to India’s low IQ, and instead become academic achievers.

Now Swanknasty has argued that even if First World conditions can lift the height and IQs of average Africans by 0.8 SD, they will not have that biological effect on the children of immigrants, because if these are as elite as I say they are, they are already well nourished.  However I would argue that being rich and educated largely doesn’t protect you from whatever malnutrition (including disease), infection, and parasite load is stunting one’s country as a whole.  And indeed, in the same height study I cited above, West African men living in England (presumably first generation immigrants who were born in the Third World) were 1.11 SD shorter than African American men and West African women were 0.48 SD shorter than African American women; so overall these elite Africans who migrated to England are 0.8 SD shorter even when compared to merely average African Americans (an apples to apples comparison would be to African American elites and would show an even greater height difference).

So if even the elite Africans who migrate to England can not escape the malnutrition of the average black African, I don’t think it’s unreasonable to expect their kids and grand-kids, who are born with the nutrition and healthcare of the First World, to be a couple inches taller and 13 IQ points smarter then they would have been in Africa.

What about British Caribbeans?

Swanknasty contends that my model can not explain the fact that the kids of Caribbean immigrants in Britain also obtain IQs in the 92-100 range, despite the fact that Caribbean immigrants are substantially less selected.  And indeed page 18 of this document shows that in 1979 , British immigrants born circa 1943 in the Caribbean averaged 10 years of education.  However figure 1 of this document shows that this birth cohort of Caribbeans overall averaged only about 5.8 years of schooling.  Thus those who migrated to Britain were 4.2 years more educated on average.

In the United States, for every year of extra schooling achieved, people seem to average 3.54 points more IQ.  Assuming a similar trend applies in the Caribbean, we should expect those who migrated to Britain to be 3.54(4.2) = 15 IQ points smarter than average Caribbeans.  According to Richard Lynn, black Caribbeans average IQ 71, so adding 15 points gives an IQ of 86.  But because of regression to the mean, their kids would be only 60% as far above the Caribbean mean, so an IQ of 80 would be expected for their kids.

However on page 51 of his 2006 book Race Differences in Intelligence, Richard Lynn noted that Caribean children born in Britain are 0.67 SD taller than Caribbean children born in the Caribbean.  Assuming British nutrition also boosts their IQs by 0.67 SD, we should expect the Caribbean immigrants born in Britain to average 90 instead of 80.  But they actually score a bit higher.

The most likely explanation is that Caribbean immigrants have acquired a lot of white genes since moving to Britain.  Indeed an article in The Guardian had this warning to British immigrants from the Caribbean: Mixed-race relationships are now so common that some ethnic groups – starting with African-Caribbean – will virtually disappear.  Given this high rate of mixing, and the tendency of mixed race people to only identify as black, it’s likely that many of the immigrant children classified as Caribbean have acquired a white parent or grandparent in the time that their families have been in Britain.