Tuesday, November 1, 2022

Looking beyond the data

 


General intelligence (g factor) as a function of alleles associated with educational attainment (Education polygenic score). (Fuerst et al. 2021, p. 165)



Among non-Hispanic European Americans, cognitive ability shows a positive correlation with Amerindian admixture. The reason is to be found in the history of European settlement.

 


 

We know that cognitive ability differs among human populations, but are those differences innate? Or are they purely cultural? The question is difficult to answer because a purely cultural difference can, over time, become innate. If you are better able to meet the demands of your culture, you will probably live longer, have more offspring, and pass on many of your characteristics. Thus, over succeeding generations, those heritable characteristics will become more and more widespread in the gene pool, and they will increasingly determine certain abilities that were initially created by culture.

 

This is a recurring problem when we try to distinguish between cultural and genetic determination. The two often run parallel to each other, and we can seemingly rule out the existence of genetic determination by showing that cultural determination runs in the same direction.

 

But there is another recurring problem in our efforts to distinguish between culture and genetics. We lack the proper tools. For a long time, we could only infer genetic influences by using twin studies or adoption studies. 

 

Things have changed with the advent of a new tool: genomic data. Specifically, we can now:

 

·         Measure ethnic ancestry in mixed populations, as opposed to using self-report or inferring from skin color.

·         Measure the genetic component of cognitive ability, by using genetic variants associated with educational attainment. Although these variants explain only 11-13% of the variance in educational attainment among individuals, they explain a much higher percentage of the variance among populations (Piffer 2019). This is because genetic variants within the same population are exposed to the same pressure of selection and will thus vary in the same direction. They act, so to speak, as “weathervanes” that tell us the strength and direction of selection in that population.

·         Measure skin color, by looking at the relevant genes. We can thus control for the effects of “colorism” in mixed populations, i.e., discrimination in favor of lighter-skinned individuals.

 

In my last post, I described how Bryan Pesta used these tools to understand differences in mean cognitive ability between African Americans and European Americans (Lasker et al. 2019). To that end, his research team looked at cognitive ability among African Americans in relation to European admixture and in relation to genetic variants associated with educational attainment.

 

They made several findings: 1) among African Americans, cognitive ability correlates with European admixture; 2) the correlation is modestly reduced, but not eliminated, when controlled for parental education; 3) controlling for skin color has no effect; and 4) the correlation seems to be largely explained by genetic variants associated with educational attainment.

 

The same data source was then used by Fuerst et al. (2021) to investigate cognitive ability not only in European Americans and African Americans but also in Hispanic Americans. The research team thus looked at cognitive ability in relation to Amerindian admixture, and not just in relation to European and African admixture.

 

Most of their findings are similar to those of the first study:

 

·         Among Hispanic Americans, cognitive ability shows a positive correlation with European admixture and a negative correlation with African admixture and Amerindian admixture.

·         Among Hispanic Americans, the correlations are reduced but not eliminated by controlling for parental education. Controlling for skin color has no effect.

·         The above correlations are partially explained by variants associated with educational attainment, but not by skin color.

·         Among non-Hispanic European Americans, cognitive ability shows a positive correlation with Amerindian admixture.

 

The last correlation may seem curious. Keep in mind that the data came from residents of Pittsburgh and that the native peoples of the Eastern U.S. intermixed mostly with early settlers of British, Dutch, or French origin. There is much less Amerindian admixture among the descendants of later immigrants from southern and eastern Europe. The correlation may thus be due not to Amerindian admixture per se but rather to variation in cognitive ability among Europeans.

 

Until the eleventh century, mean IQ was relatively low throughout Europe, perhaps hovering in the low 90s. It then rose during late medieval and post-medieval times through the expansion of the middle class. There was in fact a broad mental and behavioral change: "Thrift, prudence, negotiation, and hard work were becoming values for communities that previously had been spendthrift, impulsive, violent, and leisure loving" (Clark 2007, p. 166; see also Clark 2007, 2009a, 2009b). More people could better understand probability, cause and effect, and another person’s perspective, whether real or hypothetical (Rinderman 2018, pp. 49, 86-87; Oesterdiekhoff 2012). As the "smart fraction" grew in size, a point was reached when intellectuals were no longer voices crying in the wilderness. They were now numerous enough to form learned societies and collaborate in projects of various sorts (Frost 2019b, pp. 175-176).

 

Western Europe was where the middle class began to expand, and that was where the expansion would have its greatest impact, not only demographically but also behaviorally and cognitively. Gregory Clark (2009a) has shown that the English, even in the lower classes, are largely descended from people who were middle-class several generations earlier. The same is likely true elsewhere in Western Europe. We should therefore see a cognitive gradient between the Western European core and its periphery, as can indeed be seen between northern and southern Italy. When Piffer and Lynn (2022) looked at genomic data from that country, they found a north-south gradient in alleles associated with educational attainment. That difference corresponds to historical differences in economic development. By the 18th century, the South had already fallen behind the North; its middle class had remained small and economic relations were still structured by paternalism and familialism (De Rosa 1979).

 

All of that leads to an interesting corollary: the IQ gap used to be smaller between Europeans and sub-Saharan Africans. On the one hand, European mean IQ had probably remained in the low 90s until late medieval times. On the other hand, mean IQ may have been in the upper 80s among those Black African groups that Europeans had first encountered, particularly the Nubians. By the time of Classical Antiquity they had reached a high level of material culture, social complexity and State formation.

 

A smaller IQ gap would be in line with an observation by Jason Malloy. He noted that blacks were often described in the ancient world as having large penises but not as being less intelligent. Indeed, I have found only two Greco-Roman texts in which the writer disparaged Black Africans as being unintelligent. One of them is of doubtful authenticity, and both come from Late Antiquity (Frost 2019b). By then, blacks in the Roman world were increasingly slaves who came from farther within the African interior. Thereafter, a stereotype of low intelligence is regularly attested in Middle Eastern and European sources.

 

 

References

 

Clark, G. (2007). A Farewell to Alms. A Brief Economic History of the World. Princeton University Press: Princeton and Oxford.

 

Clark, G. (2009a). The indicted and the wealthy: surnames, reproductive success, genetic selection and social class in pre-industrial England.  http://www.econ.ucdavis.edu/faculty/gclark/Farewell%20to%20Alms/Clark%20-Surnames.pdf     

 

Clark, G. (2009b). The domestication of man: The social implications of Darwin. ArtefaCTos 2: 64-80. https://www.researchgate.net/publication/277275046_The_Domestication_of_Man_The_Social_Implications_of_Darwin

 

De Rosa, L. (1979). Property Rights, Institutional Change, and Economic Growth in Southern Italy in the XVIIIth and XIXth Centuries. Journal of European Economic History 8(3): 531-551.

 

Frost, P. (2019a). The Original Industrial Revolution. Did Cold Winters Select for Cognitive Ability? Psych 1(1): 166-181. https://doi.org/10.3390/psych1010012   

 

Frost, P. (2019b). Why that stereotype and not the other? Evo and Proud, July 28. https://evoandproud.blogspot.com/2019/07/why-that-stereotype-and-not-other.html

 

Frost, P. (2021). Commentary on Fuerst et al: Do Human Populations Differ in Their Mental Characteristics? Mankind Quarterly 62(2). http://doi.org/10.46469/mq.2021.62.2.9   

 

Fuerst, J., E.O.W. Kirkegaard and D. Piffer. (2021). More research needed: There is a robust causal vs. confounding problem for intelligence-associated polygenic scores in context to admixed American populations. Mankind Quarterly 62(1): 151-185. https://www.researchgate.net/profile/John-Fuerst/publication/354767141_More_Research_Needed_There_is_a_Robust_Causal_vs_Confounding_Problem_for_Intelligence-associated_Polygenic_Scores_in_Context_to_Admixed_American_Populations/links/614bc1dfa595d06017e4c017/More-Research-Needed-There-is-a-Robust-Causal-vs-Confounding-Problem-for-Intelligence-associated-Polygenic-Scores-in-Context-to-Admixed-American-Populations.pdf

 

Lasker, J., B.J. Pesta, J.G.R. Fuerst, and E.O.W. Kirkegaard. (2019). Global Ancestry and Cognitive Ability. Psych 1(1):431-459. https://doi.org/10.3390/psych1010034  

 

Oesterdiekhoff, G.W. (2012). Was pre-modern man a child? The quintessence of the psychometric and developmental approaches. Intelligence 40, 470–478. https://doi.org/10.1016/j.intell.2012.05.005

 

Piffer, D. (2019). Evidence for Recent Polygenic Selection on Educational Attainment and Intelligence Inferred from Gwas Hits: A Replication of Previous Findings Using Recent Data. Psych 1(1):55-75. https://doi.org/10.3390/psych1010005

 

Piffer, D., and R. Lynn. (2022). In Italy, North-South Differences in Student Performance Are Mirrored by Differences in Polygenic Scores for Educational Attainment. Mankind Quarterly 62(4), Article 2. https://doi.org/10.46469/mq.2022.62.4.2   

 

Rindermann, H. (2018). Cognitive Capitalism. Human Capital and the Wellbeing of Nations, 1st ed.; Cambridge University Press.

16 comments:

thecherryontop said...

Intelligence is genetically-based. no one can deny that. its in so much of the data.

Anonymous said...

Peter what have you worked on recently that was noteworthy? how much money do you make? i feel like youre a humble scientist trying to reach a bigger audience. but i dont know if youll succeed.

sincerely,
the man the myth the legend LOADED aka cherryontop

Unknown said...

Peter this is off topic but something you know a lot about:

Of the three main "races" as defined by Rushton, which is oldest and which is newest?

For example, did the last common ancestor of Africans and non-Africans look more like today's Africans or more like a Caucasoid or Mongoloid?

Did the last common ancestor of Caucasoids and Mongoloids look more like a Caucasoid or a Mongoloid?

The reason I ask is Rushton speculated that evolution might be progressive, with newer forms being more advanced.

Pumpkin Person said...

The last comment was from me, pumpkinperson

Peter Frost said...

Cherry,

"Noteworthy" is relative. I consider my recent paper on gene-culture coevolution with the olfactory environment to be noteworthy, but so far it hasn't excited any interest. I don't see things the same as other people do.

I'm a loner. That has its advantages and its disadvantages. I don't feel the need to conform to what people around me think. On the other hand, I'm not very good at ingratiating myself with other people and building up a network of friends who can push my ideas. Darwin was a loner, but he had a network of influential friends.

To be honest, I don't think much about self-promotion. When I write and publish a paper, I move on to the next one. I make little effort to promote myself, and it's only recently that certain people have been providing me with advice on how to broadcast my ideas.

Money? That isn't really a constraint. The main constraint is lack of co-researchers. Henry Harpending's death was a severe blow to my opportunities for joint research.

Pumpkin,

All human lineages are equally old. Your question is really which lineages are most evolutionarily conservative and which are least. The Khoisan peoples are probably the most conservative. They most closely resemble the humans who existed 50,000 years ago (the latter were larger in size, however). Europeans have clearly undergone the most change, at least morphologically.

The last common ancestor of Europeans and East Asians had straight black hair and brownish skin, while not having extreme cold adaptations (epicanthic eyefold, shorter nose, etc.).

I don't agree with the idea that newer = more advanced. It depends on the environment of adaptation.

Pumpkin Person said...

All human lineages are equally old.

True. But Rushton argued that some branched off the main trunk of the evolutionary tree later than others, creating a hierarchy. I guess he believed that earlier branches tend to be more conservative on average:

https://psychology.fandom.com/wiki/Race,_Evolution_and_Behavior?file=R%2526amp%253BA.gif


Your question is really which lineages are most evolutionarily conservative and which are least. The Khoisan peoples are probably the most conservative. They most closely resemble the humans who existed 50,000 years ago (the latter were larger in size, however).

Although I assume they would have likely been darker since proto-Khoisans perhaps lost pigment as they were driven South of the Equator by the Bantu expansion.


The last common ancestor of Europeans and East Asians had straight black hair and brownish skin, while not having extreme cold adaptations (epicanthic eyefold, shorter nose, etc.).


So what population group would the last common ancestor be most mistaken for if walking the streets today? A Native American? A Southeast Asian? A Southern European? A South Asian?
If it's the latter, could one argue Caucasoids are more conservative than Mongoloids, even if a subset of Caucasoids (Europeans) have changed a lot in coloring?



I don't agree with the idea that newer = more advanced. It depends on the environment of adaptation.


Well of course there are many exceptions so = would be way too strong, but some might argue that there's at least a small correlation between newness (whether defined by splitting off dates or appearance in the fossil record) and "more advanced".

Just trying to see what can be salvaged from Rushton's ideas.

Peter Frost said...

*** I guess he believed that earlier branches tend to be more conservative on average

Yes, earlier branches tend to remain within the same environment of adaptation, so they change more slowly. A later branch is associated with later entry into a new environment.

*** So what population group would the last common ancestor be most mistaken for if walking the streets today?

Amerindians and Austronesians are closer in physical appearance to that last common ancestor. Perhaps the Sami (Lapps) also.

*** could one argue Caucasoids are more conservative than Mongoloids, even if a subset of Caucasoids (Europeans) have changed a lot in coloring?

No, they have each evolved along different (though similar) trajectories.

*** some might argue that there's at least a small correlation between newness (whether defined by splitting off dates or appearance in the fossil record) and "more advanced".

Broadly speaking, yes. Early evolutionary change tends to target "low hanging fruit" i.e., niches that don't require high adaptive input (complex adaptations, high cognitive ability and sensorial capacity, etc.). Over evolutionary time, there are fewer and fewer low hanging fruits. Unoccupied niches thus require more and more adaptive input. Evolution thus tends to proceed from the simple to the complex (although the exceptions are numerous).

*** Just trying to see what can be salvaged from Rushton's ideas.

A lot of his ideas were right or partly right:

- the idea that cognitive ability is more important for some populations than for others. Intelligence is metabolically expensive, so people will not evolve high cognitive ability unless they really need it.

- the idea that cognitive ability is related to the mating system and reproductive behavior

- the idea that cold environments select for cognitive ability (although they are not the only such environment)

- the idea that evolution continued after human populations began to spread out of Africa. Eventually, he came around to the idea that evolution for cognitive ability continued into the Holocene and even into the time of recorded history.

He was wrong in trying to create a unified theory of everything (K and r). Humans are a product of many different selection pressures. The only unified theory is evolution by natural selection. His theory also led him to ignore or downplay the importance of recent human evolution (i.e. during the Holocene) until late in his life.

Pumpkin Person said...

Yes, earlier branches tend to remain within the same environment of adaptation, so they change more slowly.

Yes, in the case of life on Earth, earlier branches tended to remain in the ocean, while later branches evolved new forms on land. In the case of primates, early branches stayed in the trees, while newly emerged humans roamed the savannah. And among Homo Sapiens, earlier branches remained in the tropics while later branches migrated North.

The first sentence of Rushton's original 1989 paper was "Genetic distance estimates calculated from DNA sequencing indicate that in years since emergence from the ancestral hominid line, Mongoloids = 41,000, Caucasoids = 110,000, and Negroids = 200,000."

http://philipperushton.net/wp-content/uploads/2015/02/iq-race-brain-size-r-k-theory-sex-rushton-psychological-reports-12-1992.pdf

And among Caucasoids, European evolved more recently than Middle Easterners, and Ashkenazi Jews are especially recent (800 years old?)


No, they have each evolved along different (though similar) trajectories.

But it would be interesting to know which appeared first in the fossil record: Caucasoid skulls or Mongoloid skulls.


Broadly speaking, yes. Early evolutionary change tends to target "low hanging fruit" i.e., niches that don't require high adaptive input (complex adaptations, high cognitive ability and sensorial capacity, etc.). Over evolutionary time, there are fewer and fewer low hanging fruits. Unoccupied niches thus require more and more adaptive input. Evolution thus tends to proceed from the simple to the complex (although the exceptions are numerous).

Excellent analysis! Another possible reason might be that complex adaptations are useful in more diverse environments, so once you evolve an eye or a brain, new selection pressures are more likely to maintain or improve it, than to reduce or remove it (though there are exceptions)

the idea that evolution continued after human populations began to spread out of Africa. Eventually, he came around to the idea that evolution for cognitive ability continued into the Holocene and even into the time of recorded history.

Well since he was focused on the three major races which all evolved before the Holocene, I can see why he'd focus on the ice age. Also brain size stopped increasing in the Upper Paleolithic leading some to believe IQ stagnated too. Further, the birth of major cultural evolution 40,000 years ago was seen by some as largely replacing biological evolution, at least for IQ.

Although Ashkenazi Jews are likely a major exception but that's a tiny percentage of humanity with an extremely unique history and disease profile.

He was wrong in trying to create a unified theory of everything (K and r). Humans are a product of many different selection pressures. The only unified theory is evolution by natural selection. His theory also led him to ignore or downplay the importance of recent human evolution (i.e. during the Holocene) until late in his life.

Yes he tried to reduce 60 different variables to a single dimension (r vs K) which was impressively ambitious, but I fear he may have cherry picked some of his data (or even the traits themselves).

Peter Frost said...

*** But it would be interesting to know which appeared first in the fossil record: Caucasoid skulls or Mongoloid skulls.

I don't follow you. At one time, there was a proto-Eurasian population. Then, perhaps during the last ice age, that population split in two, with west Eurasians becoming Europeans and east Eurasians become East Asians. The two branches appeared at the same time.

*** Also brain size stopped increasing in the Upper Paleolithic
That finding has recently been called into question:

Overall, our conclusion is that, given a dataset more appropriate to the research question, human brain size has been remarkably stable over the last 300 ka. Thus, hypotheses of recent change are not supported by the evidence.
https://www.frontiersin.org/articles/10.3389/fevo.2022.963568/full

If the decline in brain size is real, it probably reflects the abandonment of hunting and the reduced need to store huge quantities of spatiotemporal data.

**** Although Ashkenazi Jews are likely a major exception but that's a tiny percentage of humanity with an extremely unique history and disease profile.

There are probably many other groups that have undergone recent cognitive evolution, notably the Parsis, the Igbo, and the Confucianist societies of East Asia. Unfortunately, we have less data on those groups. My wish list: polygenic edu data on the Parsis and the Igbo!!!

Anonymous said...

Peter Frost is more intelligent than Pumpkin Person.

Sincerely LOADED

Anonymous said...

the day my parents die will be the day i celebrate life! :)

Boomers need to go!

Pumpkin Person said...

I don't follow you. At one time, there was a proto-Eurasian population. Then, perhaps during the last ice age, that population split in two, with west Eurasians becoming Europeans and east Eurasians become East Asians. The two branches appeared at the same time.

The two branches leading to Caucasoids and Mongoloids appeared at the same time, but that doesn't necessarily mean the first individual who qualified morphologically as Caucasoid or Mongoloid appeared at the same time. For example, the last common ancestor of mammals and reptiles was about 325 million years ago, but the first reptiles appeared 315 million years ago (Hylonomus) while the first mammals didn't appear until 210 million years ago (morganucodontids, tiny shrew-size creatures) (if google can be trusted).


Overall, our conclusion is that, given a dataset more appropriate to the research question, human brain size has been remarkably stable over the last 300 ka. Thus, hypotheses of recent change are not supported by the evidence.


For what it's worth, I looked at the same dataset used in that paper (DeSilva (2021)) and simply divided the Homo Sapien crania into 3 time periods & got the following results

Lower Paleolithic: mean 1441 cc SD 127, n = 17

Upper Paleolithic: mean 1459 cc SD 143, n = 115

Holocene: mean 1324 cc SD 156, n = 704


If the decline in brain size is real, it probably reflects the abandonment of hunting and the reduced need to store huge quantities of spatiotemporal data.


That's plausible but I think the Occam's Razor explanation is brain size decreased for the same reason height decreased: malnutrition. And it was only with the advent of 20th century nutrition have we recovered our genetic potential for both (which also largely explains the Flynn effect which incidentally is stronger on spatial tasks)


There are probably many other groups that have undergone recent cognitive evolution, notably the Parsis, the Igbo, and the Confucianist societies of East Asia. Unfortunately, we have less data on those groups. My wish list: polygenic edu data on the Parsis and the Igbo!!!

Parsis in particular because they seem to have a disease profile similar to Ashkenazi Jews. The Kalash of Pakistan would also be very interesting because they resemble Europeans yet diverged about 12,000 years ago. If they turn out to be as smart as whites, it might be a clue that there's been virtually no Holocene cognitive evolution (with the exception of tiny ethnic groups such as Ashkenazi Jews that don't move the species average). However they may score quite low, I don't know.

Peter Frost said...

***** The two branches leading to Caucasoids and Mongoloids appeared at the same time, but that doesn't necessarily mean the first individual who qualified morphologically as Caucasoid or Mongoloid appeared at the same time.

OK, so your question is: which branch underwent the most morphological change? I would say the west Eurasians. But that's a judgment call. How do you quantify things like hair and eye color versus face shape and skin texture?

**** there's been virtually no Holocene cognitive evolution (with the exception of tiny ethnic groups such as Ashkenazi Jews that don't move the species average)

The Chinese, Koreans, and Japanese are numerous enough to move the species average, and their cognitive edge must have arisen during the time of recorded history. I also believe that Europeans in general (and not just Askhenazi Jews) underwent a rise in mean cognitive ability during historic times. For more info, you can read:

Frost, P. (2019). The Original Industrial Revolution. Did Cold Winters Select for Cognitive Ability? Psych 1(1): 166-181. https://doi.org/10.3390/psych1010012

Pumpkin Person said...

The Chinese, Koreans, and Japanese are numerous enough to move the species average, and their cognitive edge must have arisen during the time of recorded history.

Must have based on what? The fact that they score 5 points higher than Mongols? We don't know if this genetic but if it is, you might be right that civilization selected for higher IQ. But if there was Holocene selection for higher IQ, why wouldn't that also select for bigger brains by proxy? And why do Mongols have the biggest brains of any East Asian group?

Peter Frost said...

Pumpkin,

Not just the Mongols. The Evenks and Yakuts also score lower. Northern hunting peoples have bigger brains because they need to store huge quantities of spatiotemporal information when tracking prey. So brain size doesn't fully correspond to cognitive ability. I wrote about that issue in my 2019 paper:

Frost, P. (2019). The Original Industrial Revolution. Did Cold Winters Select for Cognitive Ability? Psych 1(1): 166-181. https://doi.org/10.3390/psych1010012

Ron Unz has also written about selection for cognitive ability in the Chinese population:

Unz, R. How Social Darwinism made modern China, The American Conservative 2013, March/April, 16-27. https://www.theamericanconservative.com/how-social-darwinism-made-modern-china-248/

Pumpkin Person said...

Northern hunting peoples have bigger brains because they need to store huge quantities of spatiotemporal information when tracking prey.

Possibly. Is there evidence of memory correlating with brain size independently of g?

Another explanation for why Northern hunters have lower IQs than their brain size would predict might be population size. As Lynn has argued, favorable genetic mutations are more likely in larger less isolated populations like ice age pre-farmers. So even though Northern hunters experienced even more cognitive selection to survive the cold than Northern pre-farmers, their cognitive evolution was stunted by fewer mutations for brain efficiency.

But the combination of more selection combined with less mutation was brains got extra large to compensate for their lack of efficiency in a cognitively demanding climate, but given the brain-size vs IQ correlation of only 0.4, even supersized brains are less smart than more efficient ones.