According to scientist Richard Lynn, on a scale where British and White Americans average IQ 100, black Africans average 67. However a scientist J.M. Wicherts & his colleagues say the actual average IQ in black Africa is 80. Wicherts writes:
We attribute the difference of roughly 10 IQ points between his estimate and ours to (1) our use of systematic methods and a lack thereof in Lynn’s work; (2) our use of weighting by sample size to estimate the mean IQ across samples and Lynn’s indifference to sample sizes; (3) our decision not to include unhealthy samples, which Lynn admitted; (4) our exclusion of samples in which test administration had met with problems, which Lynn attributes to low cognitive ability of test-takers; (5) our exclusion of data from the Coloured Progressive Matrices (CPM) for ages above 11 because the conversion from CPM scores to adult and adolescent norms for the Standard Progressive Matrices (SPM) artificially lowers the IQ; (6) exclusion of a number of high-IQ samples that he deemed unrepresentative; and (7) Lynn’s ad hoc downward correction of mean IQs from primary and secondary school students by two and six IQ points, respectively. Below we provide new estimates for these groups on
(1) Wicherts has a valid point that Lynn should use a systematic method for including and excluding studies, but his other criticisms are less tenable.
(2) I don’t think samples should be weighted by sample size because some of the biggest samples might be the least representative, so weighting by sample size just compounds the error.
(3) With some exceptions, Lynn is correct to include unhealthy samples because Africa is a region afflicted with poor health (malnutrition, AIDS, etc) so excluding unhealthy people largely excludes a huge percentage of Africans, making Wicherts samples unrepresentative.
(4) Wicherts is also wrong, in my humble opinion, to exclude samples where there were problems with test administration, because low IQ samples by definition are going to have more problems being administered tests, so excluding “problem testing sessions” systematically biases the numbers upward.
(5) Wicherts also excludes data from the CPM for kids older than 11. This is one area I’m not informed on, but excluding CPM scores sounds like a bad idea if you want to measure a low IQ population, because the CPM was specifically designed to have a very low floor, thus making it possible for people to score very low. By contrast the SPM has a high floor, causing low IQ people to score artificially high.
So even though Wicherts does a good job exposing the contradictions in Lynn’s research, he creates a bunch of new criteria that seems to bias the estimated IQ of Africans way up, and they are already biased up just by virtue of the fact that the most disadvantaged Africans are not in schools, urban areas, or professions, where they can be easily tested. They are isolated in poor rural areas, often don’t attend school, don’t know how to hold a pencil, can’t read, and are tragically orphaned by AIDs.
Commenter Lion of the Judah-Sphere asks:
I’m not sure if I understand the point all of this discussion over African IQ samples. I would ask: do elite Africans (average IQ 100) perform as well as elite whites (average IQ 130)? If they complete, say, Calculus 1 and 2 in high school, and rigorous engineering degree programs in university at the same rate as elite whites, then we know for sure that African IQ data is bullshit, because obviously 100 IQ in Africa means something totally different than 100 IQ in Europe or America. But if 100 IQ Africans are struggling to pass pre-calc in high school and they’re completing “engineering tech” degrees that are being called engineering, then it’s likely 100 IQ in Africa = 100 in the West. Voila! Problem solved…
The debate between Wicherts and Lynn largely concerns what the average IQ is, but that’s separate from the question Judah-Sphere is asking, which is, are the tests valid for Africans. I would say that while tests like the SPM and CPM are not as culture reduced as they appear, they do seem to be valid for comparing Africans and non-Africans with equivalent schooling. For example, if you scroll down to figure 2 of this study by J.P. Rushton, you find that the regression line predicting grades for African and non-African engineering students is roughly parallel, suggesting the test predicts very similar academic outcomes in both populations (at least in STEM).
It’s amazing to know that black African populations have such low IQs, but it’s not totally unbelievable. One of my best friends growing up had a sibling with a low IQ who was placed in special Ed classes. Recently, I asked my friend if his sister ever had her IQ tested; he claimed her FSIQ was 67. My friend is at least average intelligence, so I’m guessing his sister ended up retarded for organic rather familial reasons. Anyhow, this sibling isn’t obviously retarded when you first speak with her, but she clearly has some issues in day-to-day functioning. She graduated from high school but only took special ed classes. After high school, she got a job bagging groceries, which she somehow managed to lose in two months.
Since then, for about the past 6 years, she’s just been living with her parents, not having much in the way of employment. Apparently she steals a lot and got beaten up badly by her “boyfriend” about 2 years ago. As far as overall intellectual ability, she can perform basic arithmetic and write simple, grammatically correct sentences, but her understanding of complex rules and topics is limited.
What I mean by that: one time a few years ago I went with her and her brother to the store. Me and her brother were discussing a new townhouse development that was being constructed along a certain “Martin Luther King Drive” in our town. She said little in the course of conversation (like during most of our conversations), but she blurted out towards the end “is Martin Luther King Drive [in our town] the same street as Martin Luther King Boulevard in Dallas, Texas?”. She and her family had visited Dallas about 2 weeks prior. Dallas is a few hundred miles away from where we lived at the time. If you know anything about the US, most American cities have a street called ‘Martin Luther King’, usually in black neighborhoods. Anyhow, me and her brother just looked at each other and laughed. I think she was befuddled by our reaction.
Anyhow, in first world countries, 67 IQ people can’t function on their own, so it’s amazing to think that there are entire countries where this is the average IQ.
“It’s amazing to know that black African populations have such low IQs, but it’s not totally unbelievable.”
IQ is probably a measure of academic aptitude. Construed that way, lower IQ doesn’t mean someone can’t tie their shoe laces. In the West, it seems to be strongly correlated with species-typical intelligence.
Anyhow, in first world countries, 67 IQ people can’t function on their own, so it’s amazing to think that there are entire countries where this is the average IQ.
But in Africa the IQ is dragged down by malnutrition. Malnutrion probably doesn’t stunt g; just more specific parts of intelligence like spatial reasoning
On verbal IQ & working memory. Africans are probably much smarter than 67 so they are not the same as someone with a genetic IQ of 67
It’s the same with the Flynn effect. Past generations were stunted spatially by malnutrition but they still left great books & theories because their academic abilities were unimpaired
I meant to add this SB Kaufman link:
http://blogs.scientificamerican.com/beautiful-minds/the-heritability-of-intelligence-not-what-you-think/
Which reminds me, this friend’s sister couldn’t even tie her shoelaces until she was 10 or so! It also took her that long to read analog clock faces.
Cool! Sounds like you could do a historiometric estimate of your friend’s sister’s IQ:
https://brainsize.wordpress.com/2014/07/09/historiometric-estimate-of-oprahs-childhood-iq/
How does that happen? Are the parts of the brain involved in specific intelligence more vulnerable than the ones involved in “g”?
I’ve theorized that during malnutrition, evolution prioritizes the parts of the brain that were most needed for survival. If you believe in g, then g influences all cognition, so g would be prioritized. Also, since humans survive in groups, and thus are so dependent on group knowledge accumulated over generations (culture) and language, so verbal ability would also be preserved during malnutrition (i.e. we evolved for the nutrients to feed these parts of intelligence first).
Only when nutrition is optimum do we suddenly see a rapid rise in spatial ability (the Flynn effect). Of course verbal abilities also go up with the Flynn effect but I believe that’s a spurious schooling effect, not a genuine biological increase in ability like the spatial Flynn effect.
I guess my question: do Africans score relatively well on verbal/working memory because of high g, or educational exposure, or because of their interest in Western culture/styles of thinking?
Well the ones we test tend to be in school so education exposure plays a part, but also their level of g and their level of verbal/working memory are not stunted by prenatal malnutrition to anywhere near the degree spatial abilities are.
Also, of all the specific abilities, blacks seem genetically worst at spatial ability, probably because of lack of exposure to the ice age where you needed a good sense of direction & strong spatial ability to hunt and make tools, clothes, fire, and shelter.
“I’ve theorized that during malnutrition, evolution prioritizes the parts of the brain that were most needed for survival.”
What is the empirical evidence for this theory? It is known that in terms of malnutrition and disease that the brain allocates energy to fight disease and not grow the brain. So energy that would have been used to grow the Brian gets diverted to fighting whatever pathogens in the body.
“Also, of all the specific abilities, blacks seem genetically worst at spatial ability, probably because of lack of exposure to the ice age where you needed a good sense of direction & strong spatial ability to hunt and make tools, clothes, fire, and shelter.”
You’d still need spatial ability in barren lands. Re: abos.
Richard Lynn cited data showing verbal/scholastic abilities are relatively preserved in malnutrition while performance IQ is hit hardest
Australian aboriginals have good visual memories but that’s different from spatial ability
Can you refer me to the paper/book where Lynn proposed this? Thanks.
I recall other studies showing that Abos didn’t have abnormal visual spatial ability. I don’t recall the difference between the two.
Lynn talks about it here in the differential increases section:
My theory is that since humans are cultural animals, when nutrition is scarce, the brain feeds the verbal part of the brain first because that allows you to access cultural knowledge & thus nonverbal visual-motor talents get sacrificed
You can have a good visual memory but bad spatial ability because the latter requires you to rotate objects in the mind’s eye, rather than merely remembering details
“Lynn talks about it here in the differential increases section:”
Thanks.
“My theory is that since humans are cultural animals, when nutrition is scarce, the brain feeds the verbal part of the brain first because that allows you to access cultural knowledge & thus nonverbal visual-motor talents get sacrificed”
I’m usually a huge critic of your hypotheses, but I like this one. I’d like to see a substantial (referenced!) post on this from you.
“You can have a good visual memory but bad spatial ability because the latter requires you to rotate objects in the mind’s eye, rather than merely remembering details”
And Abos are strong on the visual but bad on the spatial. Thanks.
I liked the part in the paper talking about IQ increases when supplements were administered. Goes with the gains seen in the Bouchard paper that Jimmy cites.
http://paulcooijmans.com/genius/solar_activity.html
they are already biased up just by virtue of the fact that the most disadvantaged Africans are not in schools, urban areas, or professions, where they can be easily tested
Even if you include every single sample, which would mean including several rural/disabled/primitive, etc. samples, the IQ average comes out to 77.
“some of the biggest samples might be the least representative”
In general, larger samples will be more representative than smaller ones. Even if you select participants completely at random, if the sample size is small the probability that the sample will be unrepresentative is high. Is there a specific reason to think that the large samples in Lynn’s data set are especially unrepresentative?
Is there a specific reason to think that the large samples in Lynn’s data set are especially unrepresentative?
Yes. The Africans who are most accessible to white psychologists (and thus get tested in largest numbers) are in schools and in cities, and thus elite samples.
No white psychologist is going to go on a 50 mile hike, deep into the backwoods of Africa to test those living in shacks and huts in the middle of a war zone.
This might even be true in the United States, where the lowest IQ blacks live in dangerous ghettos where no white psychologist would dare venture, let alone dare give an IQ test.
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I don’t know how you get your data but from what I’ve seen in Nigerian performace, they seem to perform just as well or even better than elite whites in engineering schools