Monday, April 1, 2019

They really are smart ... and other surprises



Rachela - Maurycy Gottlieb (1856-1879) (Wikicommons). Ashkenazi Jews have a higher incidence of genetic variants associated with high educational attainment.



Intelligence varies from one individual to the next, and most of this variance has genetic causes. But what, exactly, are these causes? Lots and lots of genes, it seems. To be precise, if we look at the genes that influence human intelligence, we find two things:

1. They are very numerous, numbering in the thousands.

2. In general, their variants differ slightly in their effects.

This shouldn't be surprising. Evolution proceeds by tinkering, i.e., by making little changes. Big changes tend to produce big side-effects, and most side-effects are deleterious. So the genetic capacity for intelligence differs among humans through small differences at thousands upon thousands of genes. Does it follow, then, that we cannot understand these differences by looking only at a few genes? Not necessarily. Each gene is like a weathervane. If you can get enough subjects from a human population, even a few genes will tell you the direction and strength of natural selection for intelligence. 

Davide Piffer began looking at these “weathervanes” six years ago. He gathered data from different human populations on ten SNPs (single nucleotide polymorphisms) whose genetic variants are associated with differences in intelligence, specifically differences in educational attainment. Then, for each population, he estimated its genetic capacity for intelligence by calculating a "polygenic score"—the number of genetic variants associated with higher educational attainment, out of a maximum of ten.

This score correlated with population IQ (r=0.90) and with PISA scores (r=0.84). It was highest in East Asians:

East Asians have the highest frequencies of alleles beneficial to educational attainment (39%) and consistently outperform other racial groups both within the US and around the world, in terms of educational variables such as completion of college degree or results on standardized tests of scholastic achievement. Europeans have slightly lower frequencies of educational attainment alleles (35.5%) and perform slightly worse in terms of educational attainment, compared to East Asians. On the other hand, Africans seem to be disadvantaged both with regards to their level of educational attainment in the US and around the world. Indeed, Africans have the lowest frequencies of alleles associated with educational attainment (16%). (Piffer 2013)

These results were considered preliminary. Thousands upon thousands of genes influence intelligence, and here we have only ten! Perhaps chance alone produced this geographic pattern. Over the next few years, as other researchers discovered more SNPs associated with educational attainment, Davide Piffer repeated his study with more of these weathervanes.

His latest study has just come out. It uses data on 2,411 SNPs, and the polygenic score correlates even higher with population IQ (r=0.98). The geographic pattern is the same, with East Asians scoring higher than Europeans, and with Africans scoring lower.


Yes, Jews really are smart

This time, however, the highest score was obtained for Ashkenazi Jews: 

This dataset included a sample of 145 Ashkenazi Jewish individuals. The IQ of Ashkenazi Jews has been estimated to be around 110 [34]. Remarkably, their EDU polygenic score was the highest in our sample, corresponding to a predicted score of about 108, mirroring preliminary results from a smaller (N = 53) sample (Dunkel et al., 2019) [34]. (Piffer 2019)

This finding vindicates the authors of a paper written more than a decade ago. Gregory Cochran, Jason Hardy, and Henry Harpending presented evidence that the mean IQ of Ashkenazi Jews exceeds not only that of non-Jewish Europeans but also that of other Jewish groups. The most striking piece of evidence is the high incidence among Ashkenazim of four genetic disorders: Tay-Sachs, Gaucher, Niemann-Pick, and mucolipidosis type IV (MLIV). All four affect the capacity to store sphingolipid compounds that promote the growth and branching of axons in the brain. These disorders are caused by alleles that are harmful in the homozygote state and beneficial in the much more common heterozygote state, i.e., the brain receives higher levels of sphingolipids without the adverse health effects.

Ironically, these facts are coming to light at a time when Ashkenazi Jews are disappearing through low fertility and high out-marriage. Meanwhile, and not coincidentally, they are disappearing from the ranks of top winners at the U.S. Math Olympiad, the Putnam Exam, the Computing Olympiad, and other academic competitions. This decline became noticeable in the 1980s and has accelerated since the turn of the millennium (Unz 2012; Frost 2018). Jews are still present in intellectual and cultural life, but this presence is losing its dynamism and becoming a mere legacy.


African American IQ is higher than predicted

The polygenic score seems to underpredict the IQ of African Americans:

Indeed, the IQ of African Americans appears to be higher than what is predicted by the PGS (Figure 2), which suggests this cannot be explained by European admixture alone, but it could be the result of enjoying better nutrition or education infrastructure compared to native Africans. Another explanation is heterosis ("hybrid vigor"), that is the increase in fitness observed in hybrid offspring thanks to the reduced expression of homozygous deleterious recessive alleles. (Piffer 2019)

I’d propose another possible explanation: higher intelligence in African Americans may be associated with a somewhat different basket of genetic variants. Some of these variants may come from our friends the Igbos, who seem to have followed their own evolutionary path toward higher intelligence (Frost 2015). Many notable African Americans are in fact of Igbo descent, including Forest Whitaker, Paul Robeson, and Blair Underwood (Wikipedia 2019).

Davide is skeptical about this explanation, pointing out that population IQ is in line with the polygenic score he calculated for sub-Saharan African groups (Esan, Gambians, Luhya, Mende, Yoruba). None of those groups, however, are Igbo, and it's really the Igbo who stand out among West Africans in measures of intellectual and educational attainment. If only for the sake of curiosity, we should find out their polygenic score. This score may underpredict their genetic capacity for intelligence, which to some degree would be boosted by genetic variants that exist only in sub-Saharan Africa, but it should still exceed what we see for other West Africans.


Conclusion

This latest study brings to 2,411 the number of SNPs that can inform us about the genetic capacity for intelligence in different human populations. This information was more dubious when only ten SNPs were available, and the geographic pattern could be put down to chance. That argument now seems weak. If chance is causing this pattern, why do we keep getting the same one?

Sure, we can wait until we get even more relevant SNPs, but the overall picture will probably remain the same. We will get finer geographic detail. In France, for example, we will probably understand why educational attainment is so much higher in Brittany (see:  http://www.targetmap.com/viewer.aspx?reportId=5987  H/T to Philippe Gouillou). There are probably several European regions and subregions where the genetic capacity for intelligence is on a par with what we see in Ashkenazi Jews and East Asians.

In sum, these findings deserve to be better known ... and more widely discussed.


Erratum

Initially, I wrote that Davide Piffer used 127 SNPs. In fact, 127 is the number of SNPs found in the HGDP (low coverage) dataset. In the other two datasets (1000 Genomes and GnomAd), those that the main analysis was based on, there were actually 2,411 SNPs.


****
Hiatus alert ****


I'll be unable to post for the near future, probably the next three months. 


References

Cochran, G., J. Hardy, and H. Harpending. (2006). Natural history of Ashkenazi intelligence, Journal of Biosocial Science 38: 659-693.
https://antville.org/static/sites/kratzbuerste/files/AshkenaziIQ.pdf   

Frost, P. (2018). The end of Jewish achievement? Evo and Proud, May 21
http://evoandproud.blogspot.com/2018/05/the-end-of-jewish-achievement.html

Frost, P. (2015). The Jews of West Africa, Evo and Proud, July 4
https://evoandproud.blogspot.com/2015/07/the-jews-of-west-africa.html

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://www.mdpi.com/2624-8611/1/1/5

Piffer, D. (2013). Factor analysis of population allele frequencies as a simple, novel method of detecting signals of recent polygenic selection: The example of educational attainment and IQ, Mankind Quarterly 54(2): 168-200
https://www.researchgate.net/profile/Davide_Piffer/publication/260436834_Factor_Analysis_of_Population_Allele_Frequencies_as_a_Simple_Novel_Method_of_Detecting_Signals_of_Recent_Polygenic_Selection_The_Example_of_Educational_Attainment_and_IQ/links/0c9605314d28dba7ea000000/Factor-Analysis-of-Population-Allele-Frequencies-as-a-Simple-Novel-Method-of-Detecting-Signals-of-Recent-Polygenic-Selection-The-Example-of-Educational-Attainment-and-IQ.pdf 

Unz, R. (2012). The myth of American meritocracy. The American Conservative, November 28
http://www.theamericanconservative.com/articles/the-myth-of-american-meritocracy/   

Wikipedia (2019). Igbo people.
https://en.wikipedia.org/wiki/Igbo_people#Diaspora

10 comments:

Al Smith said...

Jewish men and women under 30 have the highest gay (long string) self-identification. 18.3% for men. 25.2% for women. According to Audacious Epigone, based on data from Reuters-Ipsos.

I wonder if this might have anything to do with some of these oddball sphingolipid mutations. I'm guessing it is only Ashkenazi, in terms of this level for Jews, though it seems very high for everyone. Perhaps, there are cultural factors at play, but assuming a biological basis to explain part of it, I don't think negative selection would be as high in a tight-knit, communitarian group.

Oprah-me said...

Homossexuality is correlated with: openess//intense emotionality, artistic inclination and higher verbal intelligence, so...

Remember for all homophobic trasshes... there is a bissexuality, and even in the case of ''exclusive' homossexuality, there are great arguments that reduce your misused instincts in its insignificancy, ''aryans''.

Oprah-me said...

''Only thing'' ashk were not that brigh was about their historical selective patterns... they never thought if marry very close relatives would not increase harmful diseases.

Select psychopathy to create people specialized to destroy other societies instead improve it, eliminating its problematic issues, as ''fake-religion'' [true religion is scientific existencialism] also is not a good thing.

Just sayn

Oprah-me said...

African americans seems have higher rate of abortions as well reduced fertility rates. Remember we are analysing populations in different demographic transition stage. Maybe this have some impact on these polygenic scores, maybe not.

Brian VanHooker said...

Hello, might you be knowledgeable about the origins of male pattern baldness? If so please email me at bvanhooker@hvc.rr.com. I am hoping to ask a few questions for an article I am writing.

Thank you,
Brian VanHooker
MEL Magazine

Anonymous said...

Your implication that Jewish American achievement is declining due to out-breeding, and low fertility is garbage.

The fertility rate among Ashkenazim in America is the highest of any group in the country - period. These are not Jews who intermarry.

Incidents of genes linked to congenital disorders overlap with disease - not with cerebral performance, and you are confusing correlation with causation, not to mention explicitly biased in SNP selection linked to educational/academic performance which seems to do jack shit for Asians in Noble Prize, Literary Prize, and general creative science output.

The intermarriage rate for total Jewish American community in 1990 was 43%. Nothing indicates that that is the origin of Jewish intellectual contemporary decline. Nor does anything indicate a historical correlation, when all arbelim, or mixed Jews are taken into account of purity contributing to acamic/cultural prominence. In case you are wondering already in 1950 Jewish families were 30% mixed ! No study has ever been done to indicate the transmission of the said SNPs between Ashkenazim and non-Ashkenazim origin individuals in intermarriage. In fact, a purely historical argument would argue precisely the contrary, that it was only when Jews married outside of the tribe, that society-wide contributions resulted.

Ashkenazi Jews supposedly comprise a unitary ethnicity consistent throughout the world. Surprisingly, not one study actually bothers to identify the country origin of the Ashkenazis' sampled. Perhaps someone should first invest into a proper framework for defining the groups under discussion, before making far reaching general conclusions. Israeli IQ is lower for Ashkenaz than US Askhenaz...which conicidentally is lowerst amongst highest fertility, purest "breed" Hareidim...

As is always the case with you gene-centric IQ-obsessive cookie-cutter types, you make assumptions about cultural and social performance uniquely by counting beans!

The ignorance here is staggering.

AmRusDebate

Craken said...

The future of the Jews largely hinges on how intelligent the Haredim are, and how many of them defect to the secular world in coming generations. Secular Jews are breeding themselves out of existence. Haredim are at 1.5 million or so today, but that doubles every 20 years. If 20% go secular each generation, the number of secular Jews will only continue declining up to a point around 100 years hence, as the bleed off from the Haredi will be large enough for population growth. Of course, if the Haredim are unexceptional intellectually, none of these demographic patterns will much matter.

Peter Frost said...

Al Smith,

Those figures are primarily for bisexuality, not gayness. Bisexuality is more malleable than homosexuality, especially in women. "Straight" women can become bisexual if the culture points in that direction.

Up to a certain point, intelligent people are better able to assimilate the dominant narrative, especially when it is circulated primarily through the media and higher education.

Oprah,

I'm not I understand.

Brian,

O.K. I'll get in touch.

Anon,

Uh, if you want a conversation, please don't talk abusively. Show respect for other people and their views.

The fertility rate of Jewish Americans is very low:

"While Orthodox women have birthrates that contribute to strong population growth, fertility rates among the non-Orthodox do not reach replacement level, with the college educated majority likely to average only 1.5 births by age 40."
https://link.springer.com/article/10.1007/s12397-018-9249-6

Heterozygotes for Gaucher's disease seem to have higher IQ:

"Professor Ari Zimran, who heads the Gaucher Clinic at the Shaare Zedek Medical Centre in Jerusalem, furnished us a list of occupations of 302 Gaucher patients.
Because of the Israeli medical care system, these are essentially all the Gaucher patients in the country. Of the 255 patients who are not retired and not students, 81 are in occupations that ordinarily average IQ’s greater than 120. There are 13 academics, 23 engineers, 14 scientists, and 31 in other high IQ occupations like accountants, physicians, or lawyers. The government of Israel states that 1.35% of Israeli’s working age population are engineers or scientists, while in the Gaucher patient sample 37/255 or 15% are engineers or scientists. Since Ashkenazim make up 60% of the workforce in Israel, a conservative base rate for engineers and scientists among Ashkenazim is 2.25% assuming that all engineers and scientists are Ashkenazim. With this rate, we expect 6 in our sample and we observe 37."

https://web.mit.edu/fustflum/documents/papers/AshkenaziIQ.jbiosocsci.pdf

-"Nothing indicates ..." Only a fool or a politician uses that kind of language. The evidence may be inadequate or flawed, but it's not "nothing".

"Surprisingly, not one study actually bothers to identify the country origin of the Ashkenazis' sampled."

Ashkenazis largely have their origins in the Commonwealth of Poland (before the partitions). There were also communities in Bohemia and the Rhineland, but the overwhelming majority of Jewish Americans trace their origins to what used to be Poland.

"Israeli IQ is lower for Ashkenaz than US Askhenaz..."

I've been told this many times, but nobody has been able to point me to an actual study. Can you?

"The ignorance here is staggering."

Indeed. The spelling and grammar isn't too great either.

Craken,

The Haredim understand something that most of us secular people don't: The only real life after death is in your children and grandchildren. Anything that interferes with creating that afterlife is as toxic as cyanide.



Peter Frost said...

Oprah,

I'm not sure I understand (I was typing too fast)

Anonymous said...

Is it true that Sub Saharan Africans don't have the MCPH1 Chinese scientists put in monkeys?