Stigmata
Siciliana (1964), David McLure (Wikicommons)
What
is the mean IQ of sub-Saharan Africans? There’s no clear answer. Current
estimates come from an early stage of the Flynn effect and are also distorted
by qualitative differences in cognition. Furthermore, mean IQ differs among
African groups.
At
present, there is little consensus on the mean IQ of sub-Saharan Africans.
Estimates have ranged from a low of 66 to a high of 82 (Lynn 2010; Wicherts et
al. 2010). Rindermann (2013) put forward a "best guess" of 75, which
is inexplicably much lower than the estimated African American mean of 85. Yes,
African Americans are about 20% European by ancestry, but that degree of
admixture would not cause a 10-point difference. Malnutrition? That might
depress IQ scores in some African countries but not most.
Noah
Carl (2022) has reopened the debate by inferring mean IQ from harmonized test
scores and GDP per capita. Sub-Saharan Africa looks somewhat better on the
first measure and somewhat worse on the second. Both measures correlate roughly
with mean IQ, but the correlation isn’t strong enough to tell us whether the
mean is 62, 75, or 82. Moreover, the first measure suffers from the same
problem that plagues IQ tests: Africa is just starting to experience the
secular increase in mean IQ that the West experienced during the 20th century,
i.e., the Flynn effect. By how much should we increase the estimate of mean
African IQ to adjust for Africa being at an earlier stage of the Flynn effect?
As
for the second measure, GDP per capita, the ability to create wealth is
determined not only by cognitive ability but also by other mental traits:
future time orientation (also known as time preference), willingness to follow
rules and enforce them, feelings of guilt over breaking rules, reluctance to
use violence to settle disputes, tendency toward individualism rather than
nepotism and familialism, and so on.
In
a reply to Carl’s article, Emil Kirkegaard (1922) infers mean IQ from the
Social Progress Index. But that measure is no less problematic than GDP per
capita. Social progress is driven by a basket of mental qualities, of which
cognitive ability is only one. Emil himself makes that point:
One cannot just impute IQs reliably from
non-IQ data in order to get some kind of unbiased estimates of a region's IQ
because the regions themselves may under- or overperform on international
rankings for whatever reason, [including] legacy of or current communism,
nonWEIRDness, low individualism, or any other difference you can imagine.
Emil
concludes: “There’s no avoiding having to collect more African IQ data.”
More
data would be nice, but no amount of data will provide us with a mean African
IQ that can be usefully compared with the mean IQs of other populations. There
are several reasons:
· Again,
estimates of African IQ come from an early stage of the Flynn effect. They are
not comparable with estimates of IQ that come from a later stage in other
populations.
· The
genetic architecture of cognition is not the same. Sub-Saharan Africans seem to
have alleles for cognitive ability that do not exist in other populations. To
date, such alleles have been identified only in people of European descent.
· Recent
cognitive evolution, particularly in societies near the Niger, has created differences
in mean cognitive ability among African groups. It is no more meaningful to
talk about a single mean African IQ than it is to talk about a single mean European
IQ.
Differences in the
stage of the Flynn effect
IQ
data from Western societies are not comparable with IQ data from African
societies. The latter are just beginning to experience the rise in mean IQ that
took place earlier in the West, specifically the increase of 13.8 points
between 1932 and 1978 (Flynn 1984). The Flynn effect seems to be not so much an
increase in cognitive ability as an increase in familiarity with the “test
paradigm” at school and, more broadly, in society. Flynn (2013) situates the
cause in the modernist paradigm: “We freed ourselves from fixation on the
concrete and entered a world in which the mass of people began to use logic on
abstractions and universalize their moral principles.”
Keep
in mind that competitive exams began to appear in the West only in the late
19th century, first for entry into the civil service and then more generally
for the educational system (Wikpedia 2022). Previously, people entered the
civil service through patronage appointments, and education took the form of
apprenticeship and imitation of role models. In those days, people were less
inclined to formulate questions and look for the answers. The answers were
already known, and you had to learn them. In fact, there was a stigma attached
to asking too many questions, especially in rapid-fire succession.
Differences in the
genetic architecture of cognition
As
a means to estimate cognitive ability, the IQ test is becoming superseded by
the educational polygenic score. This measure is based on SNPs that have been
shown to be associated with educational attainment. Your polygenic score is
higher to the extent that the alleles at those SNPs are associated with higher
educational attainment. It is thus a measure of innate cognitive ability. At
present, we have identified 1,271 SNPs that are associated with educational
attainment and which, together, explain 11-13% of the variance in educational
attainment among individuals (Lee et al. 2018). The educational polygenic score
has shown good reliability in predicting the IQ of individuals and even better
reliability in predicting the mean IQ of populations.
Again,
we have identified alleles associated with educational attainment only in people
of European descent. For this reason, the educational polygenic score is five
times worse at predicting the cognitive ability of African Americans (Lasker et
al. 2019). The loss of predictive power seems greatest in the domain of
language ability, according to two studies:
· Guo
et al. (2019, p. 27) found that the educational polygenic score is ten to
eighteen times worse at predicting the verbal ability of African Americans, in
comparison to White, Asian, and Hispanic White Americans. They attributed this
difference to the smaller size of the African American sample, to
gene-environment interactions, and to “significantly less than full coverage of
African genetic variants related to cognitive ability.”
· With
a sample of school-age African Americans, Rabinowitz et al. (2019) found that
the educational polygenic score fails to predict performance on a standardized
reading test but does predict pursuit of postsecondary education, getting a
criminal record (only among boys), and performance on a standardized math test
(only for one of the three cohorts).
When
modern humans began to spread out of Africa some 60,000 years ago, those left
behind began to pursue their own trajectory of cognitive evolution. The
evolutionary change seems to have been greatest in the domain of language,
i.e., the ability to express oneself in speech and writing. Polygenic scores
cannot predict innate reading ability because too many of the relevant alleles
are exclusive to the African gene pool and remain unidentified. Other relevant
alleles may simply be more important or less important in other gene pools.
Although
the educational polygenic score is based on alleles identified in Europeans, it
can still be used for rough predictions of cognitive ability among people of
African descent. Lasker et al. (2019, pp. 444-445) were able to increase its
predictive power for African Americans by almost a factor of three, i.e., an
increase from 20% to 54% of its predictive power for European Americans. They
achieved this improvement by using alleles from a much smaller subset of SNPs
that are less sensitive to decay of linkage disequilibrium.
Differences among
African groups in the trajectory of cognitive evolution
Within
the larger African trajectory of cognitive evolution, various African
populations have pursued their own sub-trajectories. This has been especially
true for populations in West Africa over the past millennium and a half. Their educational
polygenic scores vary as you go from west to east, being lowest among the Mende
(Sierra Leone) and progressively higher among Gambians, the Esan (Nigeria), and
the Yoruba (Nigeria). The Yoruba have almost the same educational polygenic
score as that of African Americans, who nonetheless are about 20% admixed with
Europeans (Piffer 2021, see Figure 7).
Before
European contact, West African societies were more complex in the north and the
east, i.e., in the Sahel and the Nigerian forest. Those areas saw the creation
of towns, the formation of states, and an increasing use of metallurgy and
luxury goods from the fourth century onward. The increase in social complexity
seems to have been driven by the development of trade along the Niger, which served
as the main trading route between the coast and the interior (Frost 2022).
In
West Africa, cognitive evolution seems to have gone the farthest among the Igbo
of the Niger delta. We have no educational polygenic data on them, but their
record of academic achievement in Nigeria, the UK, and elsewhere indicates an
unusually high level of cognitive ability (Chisala 2015).
Conclusion
We
should get more data, while recognizing the limits of what the data may tell
us. IQ tests will always be problematic, and future research should focus on
educational polygenic scores. In particular, we need to identify relevant
alleles in non-European populations. Some of those alleles may be
population-specific, and others may be universal but more important in some
populations than in others. Finally, Africa is not a monolith. Different African
populations have pursued different trajectories of cognitive evolution.
References
Carl, N. (2022). How useful are national IQs? Noah’s Newsletter, July 13. https://noahcarl.substack.com/p/how-useful-are-national-iqs
Chisala,
C. (2015). The IQ gap is no longer a black and white issue. The Unz Review, June 25.
http://www.unz.com/article/the-iq-gap-is-no-longer-a-black-and-white-issue/
Flynn,
J.R. (1984). The mean IQ of Americans: Massive gains 1932–1978. Psychological
Bulletin 95(1):29–51. https://psycnet.apa.org/doi/10.1037/0033-2909.95.1.29
Flynn, J.R. (2013). The “Flynn Effect”
and Flynn’s paradox. Intelligence 41: 851-857. http://dx.doi.org/10.1016%2Fj.intell.2013.06.014
Frost,
P. (2021). Polygenic scores and Black Americans. Evo and Proud, April 27. https://evoandproud.blogspot.com/2021/04/polygenic-scores-and-black-americans.html
Frost,
P. (2022). Recent cognitive evolution in West Africa: the Niger’s role. Evo and Proud, April 30. https://evoandproud.blogspot.com/2022/04/recent-cognitive-evolution-in-west.html
Guo,
G., Lin, M.J., and K.M. Harris. (2019). Socioeconomic and Genomic Roots of
Verbal Ability. bioRxiv, 544411.
https://www.biorxiv.org/content/10.1101/544411v1
Kirkegaard,
E.O.W. (2022). African IQs without African IQs: it’s complicated. Just Emil Kirkegaard Things. August 7. https://kirkegaard.substack.com/p/african-iqs-without-african-iqs-its?utm_source=substack&utm_medium=email
Lasker,
J., B.J. Pesta, J.G.R. Fuerst, and E.O.W. Kirkegaard. (2019). Global ancestry
and cognitive ability. Psych 1(1).
https://doi.org/10.3390/psych1010034
Lee,
J. J., Wedow, R., Okbay, A., Kong, E., Maghzian, O., Zacher, et al. (2018).
Gene discovery and polygenic prediction from a genome-wide association study of
educational attainment in 1.1 million individuals. Nature Genetics 50(8): 1112-1121. https://doi.org/10.1038/s41588-018-0147-3
Lynn,
R. (2010). The average IQ of sub-Saharan Africans assessed by the Progressive
Matrices: A reply to Wicherts, Dolan, Carlson & van der Maas. Learning and Individual Differences
20(3): 152-154. https://doi.org/10.1016/j.lindif.2010.03.009
Piffer,
D. (2021). Divergent selection on height and cognitive ability: evidence from
Fst and polygenic scores. OpenPsych.
https://openpsych.net/files/submissions/14_Divergent_selection_on_height_and_cognitive_ability_evidence_from_Fst_and_13c3ICJ.pdf
Rabinowitz,
J.A., S.I.C. Kuo, W. Felder, R.J. Musci, A. Bettencourt, K. Benke, ... and A.
Kouzis. (2019). Associations between an educational attainment polygenic score
with educational attainment in an African American sample. Genes, Brain and Behavior, e12558. https://doi.org/10.1111/gbb.12558
Rindermann,
H. (2013). African cognitive ability: Research, results, divergences and
recommendations. Personality and
Individual Differences 55: 229-233. https://doi.org/10.1016/j.paid.2012.06.022
Wicherts,
J.M., C.V. Dolan, and H.L.J. van der Maas. (2010). A systematic literature
review of the average IQ of sub-Saharan Africans. Intelligence 38: 1-20. https://doi.org/10.1016/j.intell.2009.05.002
Wikipedia. (2022). Imperial examination – Influence - West. https://en.wikipedia.org/wiki/Imperial_examination#West
7 comments:
As a means to estimate cognitive ability, the IQ test is becoming superseded by the educational polygenic score.
[...]
At present, we have identified 1,271 SNPs that are associated with educational attainment and which, together, explain 11-13% of the variance in educational attainment among individuals (Lee et al. 2018). The educational polygenic score has shown good reliability in predicting the IQ of individuals and even better reliability in predicting the mean IQ of populations.
Reliability is useless without validity. How much of the variance in cognitive ability does the educational polygenic score explain? How much of the variance in cognitive ability does the IQ score explain?
I am here before Santo starts spouting stupid shit like "IQ does not exist."
on another note dont take credit for what i say when instead the white man decides to exploit credit for what i do instead.
and yes we know africans are dumb as rocks but at least they outsmarted the malevolency of the white man did they not?
It will be very interesting with the Christianization of Sub-Saharan Africa and of the spread of Agrarian Civilization continent wide. If Clarkian Selection for Higher IQ would spread and become more effective with a larger population.
''and yes we know africans are dumb as rocks''
Look yourself in the mirror.
Literally speaking, IQ does not exist.
Anon,
That would be a logical impossibility. You can validate a measure of cognitive ability (like the educational polygenic score) with respect to another measure of cognitive ability (like IQ) but not with respect to the actual object of your measurement (cognitive ability itself).
Anon,
Africans are not as dumb as rocks. Please think before you write.
Santocool,
Literally speaking, words don't mean what we think they mean. Therefore, communication is impossible. And yet people communicate. Can you explain that paradox?
Your name doesn't exist as you do. Words are symbols invented to be associated with "things", like legends on maps.
IQ belong to the realm of object-symbol languages, mathematics too.
People learn this very basic trick to communicate one another, but symbols are not equivalent to real things thought. They/we understand by association.
Primary function of words is not give a meaning of things but a particular or differentiable identity.
Even when full scale IQ scores are the same, there are differences in the specifics. Black IQ is weighted towards memory and coding tasks and depressed on perceptual tasks, and black verbal reasoning probably would be average if cultural differences were accounted for.
If there are differences in heritability, on what cognitive functions and to what extent, it's possible for the mean black IQ to be around 100 and for the average black person to have subpar abstract and spatial reasoning.
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