Ashkenazi Jews and Intelligence

Measuring intelligence is a reasonable thing for psychologists to do. It is the most fundamental thing about our brains and it is the thing that makes us different from other animals. Psychologists did just this. Binet started in Paris in the 19th Century and gave us the concept of mental age. Children tended to score higher in tests as they learned more. Average scores in each age group give a rating which shows whether someone is developing faster or slower But the idea that it can be measured leads people to do just that, then consider the results.

Psychologists did not like what they found  so they decided to pretend that IQ measurements were irrelevant and should be ignored. There are people who think that the whole business of psychology is a boondoggle, that Freud was a fraud, a patter merchant taking advantage of neurotic women but that is another issue. There are honest men out there who tell us that the average IQ among white people is 100. This is a convenient number for an average. Blacks in America are about 15 down at 85 while blacks in Africa score around 70 which seems remarkably low. Ashkenazi Jews rate around 15 higher at 115. Asians come in at around  105.

The Economist has written about Ashkenazi Jews and their higher intelligence so perhaps they have decided to ignore the cant. La Griffe du Lion is the pseudonym of somebody else who covers the same ground and writes about these things from a much higher level than The Economist normally does albeit the men they got in are rather better than their normal hacks. Doctor Cochrane et al are taking a position on the reasons for higher intelligence. La Griffe's articles are worth reading. Find them at La Griffe du Lion  - this one covers the same ground ASSESSING THE ASHKENAZIC IQ


The evolution of intelligence

Natural genius?
Jun 2nd 2005
From The Economist print edition

The high intelligence of Ashkenazi Jews may be a result of their persecuted past

THE idea that some ethnic groups may, on average, be more intelligent than others is one of those hypotheses that dare not speak its name. But Gregory Cochran, a noted scientific iconoclast, is prepared to say it anyway. He is that rare bird, a scientist who works independently of any institution. He helped popularize the idea that some diseases not previously thought to have a bacterial cause were actually infections, which ruffled many scientific feathers when it was first suggested. And more controversially still, he has suggested that homosexuality is caused by an infection.

Even he, however, might tremble at the thought of what he is about to do. Together with Jason Hardy and Henry Harpending, of the University of Utah, he is publishing, in a forthcoming edition of the Journal of Biosocial Science, a paper which not only suggests that one group of humanity is more intelligent than the others, but explains the process that has brought this about. The group in question are Ashkenazi Jews. The process is natural selection.

History before science
Ashkenazim generally do well in IQ tests, scoring 12-15 points above the mean value of 100, and have contributed disproportionately to the intellectual and cultural life of the West, as the careers of Freud, Einstein and Mahler, pictured above, affirm. They also suffer more often than most people from a number of nasty genetic diseases, such as Tay-Sachs and breast cancer. These facts, however, have previously been thought unrelated. The former has been put down to social effects, such as a strong tradition of valuing education. The latter was seen as a consequence of genetic isolation. Even now, Ashkenazim tend to marry among themselves. In the past they did so almost exclusively.

Dr Cochran, however, suspects that the intelligence and the diseases are intimately linked. His argument is that the unusual history of the Ashkenazim has subjected them to unique evolutionary pressures that have resulted in this paradoxical state of affairs.

Ashkenazi history begins with the Jewish rebellion against Roman rule in the first century AD. When this was crushed, Jewish refugees fled in all directions. The descendants of those who fled to Europe became known as Ashkenazim.

In the Middle Ages, European Jews were subjected to legal discrimination, one effect of which was to drive them into money-related professions such as banking and tax farming [ a cynical term but thoroughly justified - Editor ] which were often disdained by, or forbidden to, Christians. This, along with the low level of intermarriage with their gentile neighbours (which modern genetic analysis confirms was the case), is Dr Cochran's starting point.

He argues that the professions occupied by European Jews were all ones that put a premium on intelligence. Of course, it is hard to prove that this intelligence premium existed in the Middle Ages, but it is certainly true that it exists in the modern versions of those occupations. Several studies have shown that intelligence, as measured by IQ tests, is highly correlated with income in jobs such as banking.

What can, however, be shown from the historical records is that European Jews at the top of their professions in the Middle Ages raised more children to adulthood than those at the bottom. Of course, that was true of successful gentiles as well. But in the Middle Ages, success in Christian society tended to be violently aristocratic (warfare and land), rather than peacefully meritocratic (banking and trade).

Put these two things together—a correlation of intelligence and success, and a correlation of success and fecundity—and you have circumstances that favour the spread of genes that enhance intelligence. The questions are, do such genes exist, and what are they if they do? Dr Cochran thinks they do exist, and that they are exactly the genes that cause the inherited diseases which afflict Ashkenazi society.

That small, reproductively isolated groups of people are susceptible to genetic disease is well known. Constant mating with even distant relatives reduces genetic diversity, and some disease genes will thus, randomly, become more common. But the very randomness of this process means there should be no discernible pattern about which disease genes increase in frequency. In the case of Ashkenazim, Dr Cochran argues, this is not the case. Most of the dozen or so disease genes that are common in them belong to one of two types: they are involved either in the storage in nerve cells of special fats called sphingolipids, which form part of the insulating outer sheaths that allow nerve cells to transmit electrical signals, or in DNA repair. The former genes cause neurological diseases, such as Tay-Sachs, Gaucher's and Niemann-Pick. The latter cause cancer.

That does not look random. And what is even less random is that in several cases the genes for particular diseases come in different varieties, each the result of an independent original mutation. This really does suggest the mutated genes are being preserved by natural selection. But it does not answer the question of how evolution can favour genetic diseases. However, in certain circumstances, evolution can.

West Africans, and people of West African descent, are susceptible to a disease called sickle-cell anaemia that is virtually unknown elsewhere. The anaemia develops in those whose red blood cells contain a particular type of haemoglobin, the protein that carries oxygen. But the disease occurs only in those who have two copies of the gene for the disease-causing haemoglobin (one copy from each parent). Those who have only one copy have no symptoms. They are, however, protected against malaria, one of the biggest killers in that part of the world. Thus, the theory goes, the pressure to keep the sickle-cell gene in the population because of its malaria-protective effects balances the pressure to drive it out because of its anaemia-causing effects. It therefore persists without becoming ubiquitous.

Dr Cochran argues that something similar happened to the Ashkenazim. Genes that promote intelligence in an individual when present as a single copy create disease when present as a double copy. His thesis is not as strong as the sickle-cell/malaria theory, because he has not proved that any of his disease genes do actually affect intelligence. But the area of operation of some of them suggests that they might.

The sphingolipid-storage diseases, Tay-Sachs, Gaucher's and Niemann-Pick, all involve extra growth and branching of the protuberances that connect nerve cells together. Too much of this (as caused in those with double copies) is clearly pathological. But it may be that those with single copies experience a more limited, but still enhanced, protuberance growth. That would yield better linkage between brain cells, and might thus lead to increased intelligence. Indeed, in the case of Gaucher's disease, the only one of the three in which people routinely live to adulthood, there is evidence that those with full symptoms are more intelligent than the average. An Israeli clinic devoted to treating people with Gaucher's has vastly more engineers, scientists, accountants and lawyers on its books than would be expected by chance.

Why a failure of the DNA-repair system should boost intelligence is unclear—and is, perhaps, the weakest part of the thesis, although evidence is emerging that one of the genes in question is involved in regulating the early growth of the brain. But the thesis also has a strong point: it makes a clear and testable prediction. This is that people with a single copy of the gene for Tay-Sachs, or that for Gaucher's, or that for Niemann-Pick should be more intelligent than average. Dr Cochran and his colleagues predict they will be so by about five IQ points. If that turns out to be the case, it will strengthen the idea that, albeit unwillingly, Ashkenazi Jews have been part of an accidental experiment in eugenics. It has brought them some advantages. But, like the deliberate eugenics experiments of the 20th century, it has also exacted a terrible price.




Henry Harpending, who co-wrote the paper with Dr Cochran and Jason Hardy, has a draft of their study. Cambridge University Press has details about the Journal of Biosocial Science.

Ashkenazi Jews ex Wiki
Ashkenazi Jews, also known as Ashkenazic Jews or simply Ashkenazim (Hebrew: אַשְׁכְּנַזִּים, Ashkenazi Hebrew pronunciation: [ˌaʃkəˈnazim], singular: [ˌaʃkəˈnazi], Modern Hebrew: [aʃkenaˈzim, aʃkenaˈzi]; also יְהוּדֵי אַשְׁכֲּנַז Y'hudey Ashkenaz, lit. "The Jews of Germany"),[15] are a Jewish diaspora population who coalesced as a distinct community of Jews in the Holy Roman Empire around the end of the 1st millennium.[16] The traditional diaspora language of Ashkenazi Jews consisted of various dialects of Yiddish.

They settled and established communities throughout Central and Eastern Europe, which had been their primary region of concentration and residence from the Middle Ages until recent times, evolving their own distinctive characteristics and diasporic identities.[17] In the late Middle Ages, the center of gravity of the Ashkenazi population shifted steadily eastward,[18] out of the German lands into Poland and Lithuania (including present-day Belarus and Ukraine).[19][20] In the course of the late 18th and 19th centuries, those Jews who remained in or returned to the German lands experienced a cultural reorientation; under the influence of the Haskalah and the struggle for emancipation, as well the intellectual and cultural ferment in urban centers, they gradually abandoned the use of Yiddish, while developing new forms of Jewish religious life and cultural identity.[21]

Throughout their sojourn in Europe, the Ashkenazim made many important contributions to European culture (Hannah Arendt),[22] and made a "quite disproportionate and remarkable contribution to humanity" (Eric Hobsbawm[23]) in all fields of endeavour: philosophy, scholarship, literature, art, music and science.[24][25] The genocidal impact of the Holocaust, the mass murder of approximately six million Jews during World War II, devastated the Ashkenazim and their diaspora culture, affecting almost every Jewish family.[26][27]

It is estimated that in the 11th century Ashkenazi Jews composed only three percent of the world's Jewish population, while at their peak in 1931 they accounted for 92 percent of the world's Jews. Immediately prior to the Holocaust, the number of Jews in the world stood at approximately 16.7 million.[28] Statistical figures vary for the contemporary demography of Ashkenazi Jews, oscillating between 10 million[1] and 11.2 million.[2] Sergio DellaPergola in a rough calculation of Sephardic and Mizrahi Jews, implies that Ashkenazi make up less than 74% of Jews worldwide.[29] Other estimates place Ashkenazi Jews as making up about 75% of Jews worldwide.[30]

Genetic studies on Ashkenazim—researching both their paternal and maternal lineages—point to a significant prevalence of West Asian origins. But they have arrived at diverging conclusions regarding both the degree and the sources of their European ancestry.[31] These diverging conclusions focus on the extent of the European genetic origin observed in Ashkenazi maternal lineages.

Ashkenazi Jews are popularly contrasted with Sephardi Jews, also called Sephardim, who are descendants of Jews from the Iberian Peninsula (though there are other groups as well). There are some differences in how the two groups pronounce certain Hebrew letters and in points of ritual.


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Updated  on  Sunday, 14 August 2016 13:37:40