Monday, May 30, 2022

Recent cognitive evolution: The case of Ashkenazi Jews


Old Jewish cemetery in Prague (Wikicommons - Uoaei)

The 11th century seems to be the time when cognitive evolution began to accelerate among Ashkenazi Jews. In terms of mean cognitive ability, they would end up surpassing not only Christian Europeans but also other Jewish populations. 



In a previous post, I described how Christianity restarted cognitive evolution after a decline during Classical Antiquity, specifically by supporting the formation of monogamous families, by discouraging slavery, at least during the long period from 500 to 1500 AD, and eventually by creating the peace, order, and stability that allowed the middle class to expand and become dominant (Frost 2022).


I will now describe a parallel evolution that occurred under Judaism, particularly within its Ashkenazi branch, i.e., the Jewish communities of Central and Eastern Europe. This cognitive evolution is indicated by four lines of evidence:


·         A high polygenic score for alleles associated with educational attainment (Dunkel et al. 2019; Piffer 2019).

·         High incidences of nine neurological disorders of genetic origin: Tay-Sachs (two unrelated alleles), Gaucher's (five unrelated alleles), Niemann-Pick, and Mucolipidosis Type IV. These mutations affect the capacity of neural tissue to store sphingolipids, which are vital to the growth of neurons in the brain. All nine of them have arisen independently in the same metabolic pathway and have become unusually common in the same population over a relatively short time, perhaps a thousand years (Cochran et al. 2006; Diamond 1994).

·         A mean IQ that exceeds not only that of non-Jewish Europeans but also that of other Jewish groups. This cognitive advantage seems to be relatively recent, originating probably in the Middle Ages (Cochran et al. 2006).

·         A high proportion of Nobel Prize winners: 14% in the first half of the 20th century, 29% in the second half of the 20th century and, so far, 32% in the 21st century (Murray 2007, p. 30).


Within the Ashkenazi community, cognitive evolution was driven largely by specialization in trade, particularly in family-run businesses that operated in the increasingly dynamic economic environment of post-medieval Europe. This class of people, though proportionately smaller, would also contribute to the cognitive evolution of Christian Europeans. "They were not specialized craftsmen in life-trades with skills developed through long years of apprenticeship; they were semi-skilled family labour teams which set up in a line of business very quickly, adapting to shifts in market demand" (Seccombe, 1992, p. 182). The workforce was the household. In more successful households, the parents would have as many children as possible, and the children would marry earlier and start their own households earlier. In less successful ones, the children would postpone marriage or never marry.


This demographic model explains not only the cognitive evolution of Ashkenazi Jews but also their impressive population growth between the 16th and 19th centuries (Frost 2007). It is also the same model that Gregory Clark (2007) used to describe the mental and behavioral shift of the English population during medieval and post-medieval times: demographic success was closely linked to economic success, which in turn was linked to possession of cognitive ability and “middle-class” traits (low time preference, high impulse control, thrift, etc.).


For Ashkenazi Jews during the same time period, cognitive evolution was also assisted by a ban on polygyny. Around 1000 AD, a Jewish synod at Mainz, Germany forbade men to take more than one wife. The ruling was made for several reasons: (1) to reduce “quarreling” within the family; (2) to deter men from abusing their wives; (3) to prevent de facto divorce (i.e., abandonment of the first wife in her own household); and (4) to prevent the husband’s financial resources from being spread too thinly over several wives (Dinonline 2015). The ban on polygyny strengthened the reproductive importance of upper-class women by reducing female hypergamy. In particular, it prevented the classic case of a wealthy man taking a second wife who would be younger than the first but lower in social status … and thus less likely to have the mental and behavioral characteristics that had made him economically successful and able to afford polygyny.


The polygyny ban was accepted by Ashkenazi Jews but not by Sephardic Jews (Dinonlne 2015). This may explain why cognitive evolution was weaker among the latter than among the former. In addition, the Sephardim were operating within a much less dynamic economic environment, particularly during the period from the 16th to 19th centuries that saw so much population growth among the Ashkenazim. 


Reconstructing cognitive evolution


Until recently, it was possible to reconstruct cognitive evolution only by looking at present-day genomes and making inferences about the past. We can now look directly at past cognitive evolution by examining DNA from human remains. For example, when Woodley et al. (2017) compared DNA from sites across Europe and central Asia, they found a net increase between 4,560 and 1,210 years ago in the frequency of alleles associated with high educational attainment.


Unfortunately, that kind of longitudinal data is not yet available for Ashkenazi Jews. But we have a proxy: alleles that affect sphingolipid storage, specifically those for Tay-Sachs, Gaucher’s, Niemann-Pick and Mucolipidosis Type IV. An allele for Gaucher’s disease, and specific to Ashkenazi Jews, has been retrieved from the remains of 33 Jewish individuals who had lived in Erfurt, Germany during the 14th century (Waldman et al. 2022, p. 16).  Those individuals were not directly ancestral to modern Ashkenazi Jews; instead, both groups seem to descend from a common ancestral population that probably existed in the 11th century, when Jewish merchants first became established in Erfurt (Waldman et al. 2022; Wikipedia 2022a). That date is consistent with the estimated time of origin of the allele for Gaucher’s disease, which has been dated to a period between the 11th and 13th centuries (Colombo 2000).


A time of origin in the 11th century is also consistent with the founding of Jewish communities in what is now the Czech Republic and Poland:


We have already mentioned the existence of Jewish traders in Prague in the late tenth century. The biographies of St. Adalbert tell us that they trafficked in slaves. There was also in the early eleventh century, we will discuss further, a Jewish establishment at Przemysl, a town at the crossroads of two trading routes: Prague-Krakow-Kiev and Hungary-Kiev. The importance of this center is confirmed by the discovery, in the mid nineteenth century, of a great treasure of dirhams [Arab silver money] from the Iranian dynasty of the Samanids, dating from the first half of the tenth century. We will see that certain Hebrew documents from the 11th and 12th centuries also report the trade of Rhineland Jewish merchants with Poland. Gallus Anonymus, the famous Polish chronicler of the 11th century, relates that Queen Judith repurchased slaves in Poland from Jewish traders—which also proves the existence of this trade. A final confirmation of this phenomenon: the discoveries of Polish “treasures of silver” [hoards] from the 10th and 11th centuries, which have very many coins from the Rhineland towns of Western Europe. (Lewicki 1960, p. 232)


The importance of that trade is also indicated by the large number of Slavic words that appear in the works of contemporary Jewish authors from the Rhineland and even northern France (Lewicki 1960, pp. 236-237).


It looks like Ashkenazi communities entered an upward economic trend not long before the 11th century. This was a time when both the State and the Church began pacifying the social environment of Western Europe (Frost and Harpending 2015; Head 1992; Wikipedia 2022b). Trade thus became safer. In particular, slave merchants were able to establish long trade routes that ran from the lands of the pagan Slavs, across Western Europe, and into the Islamic world via Muslim Spain (Blumenkranz 1960; Korn 1971; Skirda 2010, pp. 83-120). Erfurt itself was one of several stops on a route from Bohemia to Spain (Skirda 2010, p. 115). It is likely, then, that the 11th century coincides with the time when cognitive evolution began to accelerate among Ashkenazi Jews.


After the 11th century, the slave trade began to lose importance, and other activities gradually took their place. There were a number of reasons. Trade with the Muslim world was disrupted by the Reconquista of Spain and by the Crusades in general. Throughout Western Europe, Jewish communities were accused of having Muslim sympathies and suffered persecution (Skirda 2010, pp. 104-105). Above all else, the Slavs were converting to Christianity, and their enslavement was becoming harder to justify.


Ashkenazi Jews thus shifted toward other activities. At first, they turned to trade with Central Asia via Kiev and the Black Sea (Skirda 2010, p. 105). In time, their interest focused on Europe, which was developing economically and offering many more opportunities. The result was a demographic expansion. From an estimated 25,000 in 1300, the Jewish population of Eastern Europe would grow to 50,000 by 1490, 250,000 after the mid-1600s, 910,000 by 1765, two and a quarter million by 1825, over five and a half million by 1880, and over eight and a half million by 1900 (DellaPergola 2001, p. 12).




Blumenkranz, B. (1960). Juifs et Chrétiens dans le monde occidental. Paris: Imprimerie nationale


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


Cochran, G., J. Hardy, and H. Harpending. (2006). Natural history of Ashkenazi intelligence. Journal of Biosocial Science 38(5): 659-693.


Colombo, R. (2000). Age estimate of the N370S mutation causing Gaucher disease in Ashkenazi Jews and European populations: A reappraisal of haplotype data. American Journal of Human Genetics 66(2):692-697.


DellaPergola, S. (2001). Some fundamentals of Jewish Demographic History. In: S.DellaPergola, and J.Even (eds.) Papers in Jewish Demography 1997, (pp. 11-33), Jerusalem: The Hebrew University.


Diamond, J.M. (1994). Jewish Lysosomes. Nature 368: 291-292.


Dinonline. (2015). Marrying more than one wife: The decree of Rabbeinu Gershom — Then and today. November 18.


Dunkel, C.S, M.A. Woodley of Menie, J. Pallesen, and E.O.W. Kirkegaard. (2019). Polygenic scores mediate the Jewish phenotypic advantage in educational attainment and cognitive ability compared with Catholics and Lutherans. Evolutionary Behavioral Sciences 13(4): 366-375.


Frost, P. (2007). Natural selection in proto-industrial Europe. Evo and Proud, November 16


Frost, P. (2022). When did Europe pull ahead? Evo and Proud, May 16


Frost, P. and H. Harpending. (2015). Western Europe, state formation, and genetic pacification. Evolutionary Psychology 13(1): 230-243.


Head, T.F. (1992). The Peace of God: Social Violence and Religious Response in France around the Year 1000. Cornell University Press.


Korn, B.W. (1971). Slave Trade. Encyclopaedia Judaica 14: 1660-64. Jerusalem: MacMillan.


Lewicki, T. (1961). Les sources hébraïques consacrées a l'histoire de l'Europe centrale et Orientale et particulièrement a celle des pays slaves de la fin du IXe au milieu du XIIIe siècle. Cahiers du Monde russe et soviétique 2(2): 228-41.


Murray, C. (2007). Jewish Genius. Commentary. April: 29-35


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: 55–75.


Seccombe, W. (1992). A Millennium of Family Change. Feudalism to Capitalism in Northwestern Europe. London: Verso.


Skirda, A. (2010). La traite des Slaves. L’esclavage des Blancs du VIIIe au XVIIIe siècle. Paris: Les Éditions de Paris Max Chaleil.


Waldman, S., D. Backenroth, É. Harney, S. Flohr, N.C. Neff, G.M. Buckley, et al. (2022). Genome-wide data from medieval German Jews show that the Ashkenazi founder event pre-dated the 14th century. bioRxiv 2022.05.13.491805.


Wikipedia. (2022a). Erfurt.


Wikipedia. (2022b). Peace and Truce of God.


Woodley, M.A., S. Younuskunju, B. Balan, and D. Piffer. (2017). Holocene selection for variants associated with general cognitive ability: comparing ancient and modern genomes. Twin Research and Human Genetics 20: 271-280.   



Anonymous said...

And as demonstrated sub-optimal else said cognitive evolution wouldn't came with downsides of those diseases. It's best to have more well rounded evolutionary pressure that over time enhances physical fitness as much as cognitive ability. Without the genetic diseases.

Without said too rapid cognitive evolution.

Luke Lea said...

Why no mention of the importance of Talmudic study and the practice of the most successful, and presumably brightest verbally, students (often the sons of rabbis?) marrying the daughters of the most successful merchants in a town? Surely this would have had a positive effect on verbal intelligence, at which Ashkenazi excel.

Al Smith said...

Wonder if there are any clues in the DNA to support the idea that the non-Jewish component of Ashkenazis came from slaves. (I think it matches up with the timeline.)

In that way, getting European adaptations to the environment, for example, paler skin variants, I think slavery would be considered a genetic positive for them.

Maybe, it was the same in the South for spreading adaptations against malaria.

I've often wondered how the Chinese were able to move into Southern China. Some people seem to say malarial adaptations. Perhaps, they got these from slavery and polygamy.

Santocool said...

They score high in verbal IQ and have high incidence of people with bipolar disorder... hmmm said...

If we consider the slave market was about millions of people and if you have no qualm for picking the best for yourself, you can include a lot of useful genes in the gene pool of the community.

It is pretty sure the female slaves/servants taken by the Jews as wives/concubines must be "very high quality" compared to the rest of the population.

Peter Frost said...


Sometimes, the "best" is suboptimal. During the Second World War, the British said they weren't interested in developing the "best" tanks or the "best" equipment. They wanted tanks and equipment that could be produced NOW.


Talmudic study was equally important for Ashkenazi and Sephardic Jews. Yet cognitive evolution seems to have been stronger among the Ashenazi.

Al Smith,

Perhaps. That's Greg Cochran's argument. Admixture enables a population to tap into alleles from other populations. Actually, it doesn't matter where a new beneficial allele comes from. What matters is the selection pressure on that allele.


There are always trade-offs. In time, those adverse effects will decline as better alleles become available.


The problem is that men often choose concubines solely for their sexual attractiveness. That's why polygyny is either banned or highly restricted in many societies. It facilitates hypergamy by women who have suboptimal behavioral and mental characteristics.

Anonymous said...

"Sometimes, the "best" is suboptimal. During the Second World War, the British said they weren't interested in developing the "best" tanks or the "best" equipment. They wanted tanks and equipment that could be produced NOW."

True. r-selected organisms are the most successful organisms on this earth and they are the least likely to go extinct.

But the Ashkenazi case goes to show that too much of an singular selection pressure on cognitive ability too fast without said set of genes having its subsequent downsides ironed out by selection.

Hence resulting in a better Polygenetic profile that would have occurred far sooner.
I suspect genetic screening whilst beneficial in the short term would ensure that said bad traits will remain too common because it isn't selected out. But the other side is a sufficently large population size to ensure purifying selection doesn't result in problems itself. said...

My suspicion is selection works better "killing" unfits so they don't reproduce, not making the most fit reproduce more. Everyone reproduces as much as possible if conditions allow.
It is like with the Russian/s domestic foxes:
they started with semi-feral, then they didn't select the most playful and bred them, they killed the most feral and breed them with more semi-feral until, many generations later, they become meek and playful.

Your citation "They were not specialized craftsmen in life-trades with skills developed through long years of apprenticeship; they were semi-skilled family labour teams which set up in a line of business very quickly, adapting to shifts in market demand" (Seccombe, 1992, p. 182)." made me think.

Jews being forces by trade or by persecution to move from place-to-place way more often than the locals, prevented them from entering specialized trades, because this means you must stay put and serve the same market. This also makes keeping slaves and servants difficult as they can easily run away.

This is way more demanding for intelligence than work specialization. It is about how fast you can learn, not how diligently you can perform (your skill or trade). The consequences of not learning fast is death/starvation/poverty. The consequence of learning fast and being forced to move is the ability to tap into the most lucrative markets at the time, get wealthy and reproduce.

The Jewish laws concerning slavery/serfdom made unlawful to keep a not Jewish slave for more than one year: The girls would to convert (and get freed) or be sold to a not Jewish owner. We can suppose a rapid rotation of girls developed because of the slave trade.
During the trip the girls could be observed and the best to pick up the news skills required would be favored as candidate for conversion and introduction in the family.

Practically, the trip was a very big test and the higher in IQ, conscientiousness and agreeableness were favored to be picked up by the Jews themselves. Maybe not in the family of the slavers but "sold out" to other male Jews looking for good wife material.

"IQ, conscientiousness and agreeableness" are the traits involved in European mate selection you write so much. Jews had no formal problems with the racial origin of the woman if she converted. If the family had serious input in the choices of the groom, I would see them picking a Tamar-like girl for him if not Jewish woman of adequate quality was available in the community.

Santocool said...


There are always trade-offs. In time, those adverse effects will decline as better alleles become available.''

Jews have twice as many LGBTs, lefthanded and people with mental disorders, than Gentiles.

Jews, especially purebred Jews, tend to have a less appreciable physical appearance, suggesting that they have not undergone major sexual selection, worsened by a higher rate of inbreeding.

A small, endogamous population has a positive side in that certain traits can be transmitted quickly.

Jews began to have problems of obesity and other metallobic diseases earlier than other populations. It is a population that has adapted much more in urban environments and has lost, statistically, many [psycho-physical] characteristics, advantageous in rural environments, if this loss has not started since the first civilizations in the Middle East.

They lost certain traits to gain others.

Giftedness is a mutation, especially one that relates to creative ability.

If there's a disproportion of gifted Jews, who aren't just '' A'+students'', then we have an equal disproportion of people with mental eccentricities, including disorders.

It is impossible to naturally eliminate traits that have been present among us since the beginning of our species. It is possible to try, but there will always be a load of mutations, as long as the human being does not become a cyborg.

It is possible to think that the ''creative classes'' of other populations present profiles similar to those of Ashkenazi Jews, but more exaggerated because they do not represent their respective populations, but specific niches.

Still on the unusual cognitive profile of this population, any major imbalance among cognitive abilities tends to be a sign of some mental eccentricity, which tends to be a mental disorder.

Peter Frost said...


"Jews being forces by trade or by persecution to move from place-to-place way more often than the locals, prevented them from entering specialized trades"

This was a general trend throughout Europe (see the Wiki entry on Proto-industrialization"

In short, Ashkenazi Jews went into cottage industry because the economic return was interesting and because they were able to move into that economic niche. Other regional groups moved into the same niche around the same time.


You're always accusing me of promoting anti-gay stereotypes (which I don't). But here you are promoting a lot of anti-Jewish stereotypes. Could you at least back up your claims by providing some references to the scientific literature?

Santocool said...

I'm not accusing you. His writings are overwhelming evidence.

I thought the Jews had flaws too, just like everyone else...


Anonymous said...

good old santocool is obviously a sworn anti-semite hater and open nazi - a shame for the gay community and model of/for nazi-SA (which consisted in its leading ranks around roehm&co of many homosexuals). great part of his slander & vicious attacks stems from the fact that mosaic law punished homosexuality with death - thus forcing all intelligent bi/homosexuals at least to marry and make babies - thus preventing the evolutionary dead-end (like for santo) and exclusion from the future gene-pool. jewish communities - both ashkenazi and sephardic never had anythning like monasteries, where gay peole could find a cultural tolerated safe space with regards of not bding forced into marriage / child producing/bearing.

Santocool said...

There are desproportion of jews who are psycho/sociopaths. Why i would an exception for them?? I'm glad i will not have a miserable being to suffer this hell full of retard and evil like you. I actually hate all human groups without exception. Whites?? For each Mozart there are 3 million of Bolsonaro...

I'm totally anti nazi. They are/werw retard as well.