Jews and intelligence

The relationship between Jews and intelligence is controversial and related to other issues such as race and intelligence, Jewish influence, and Jewish group evolutionary strategy.

IQ studies

Richard Lynn, reviewing earlier IQ studies on Jews, in 2011 stated the measured average IQs of different groups as:

• Ashkenazi Jews: 110
• Sephardi Jews: 98
• Mizrahi Jews: 91
• Ethiopian Jews: 68

Ashkenazi Jews score relatively higher on verbal/mathematical subtests than on spatial subtests. Lynn argued that this is reflected by Ashkenazi Jews having performed relatively worse in areas such as visual arts, architecture, and engineering. These areas depend to a large degree on spatial abilities.

Studies from the beginning of the 20th century have sometimes been cited as contradicting high IQ among Ashkenazi Jews. A 2006 paper stated that this is "a widely cited misrepresentation by Leon Kamin (Kamin, 1974) of a paper by Henry Goddard (Goddard, 1917). Goddard gave IQ tests to people suspected of being retarded, and he found that the tests identified retarded Jews as well as retarded people of other groups. Kamin reported, instead, that Jews had low IQs, and this erroneous report was picked up by many authors including Stephen Jay Gould, who used it as evidence of the unreliability of IQ tests (Seligman, 1992)." Both Kamin and Gould were Jews. Also other Jews have considered the issue sensitive. Richard Herrnstein, one of the authors of The Bell Curve, wanted to exclude the paragraphs on Jewish IQ.

Average IQ of Israel

The measured average IQ of Israel is 95, which may seem contradictory. However, while Ashkenazi Jews are the overwhelming majority of Jews outside Israel, the situation in Israel is different. In Israel, addition to Ashkenazi Jews, there are large groups of non-Ashkenazi Jews, Palestinians, as well as various small minorities. Also, many of the supposed Ashkenazi Jews in Israel are from countries such as Russia and are (according to Israeli demographers) often not actually Ashkenazi Jews or only so partially. This since many people have posed as Jews for reasons such as being able to emigrate from the Soviet Union. This has caused the measured average IQ of Israeli "Ashkenazi Jews" to be lower than the measured average IQ of non-Israeli Ashkenazi Jews.

Proposed explanations

Eugenics

The eugenic hypothesis argues that Jews, and in particular, Ashkenazi Jews, have actually practiced eugenics. Judaism is argued to have had a long tradition of giving high status and some wealth to scholars, which allowed those with higher intelligence to more easily reproduce and their children to survive. The Mishnah states that "under all circumstances a man should sell everything he possesses in order to marry the daughter of a scholar, as well as to give his daughter to a scholar in marriage…. Never should he marry his daughter to an illiterate man". Jews have also practiced negative eugenics, by disallowing marriages for poor (and likely less intelligent) Jews during certain periods, when states explicitly limited the number of Jews. Poor Jews have also been particularly likely to leave Judaism. In contrast to Catholic priests, which may have caused a dysgenic effect on Europeans through their sometimes enforced celibacy, Jewish Rabbis were encouraged to marry young and have children. Rabbis were also often physicians, which may have caused better medical care for their children.

This can explain why Ashkenazi Jews score relatively better on verbal subtests, since it was verbal ability, rather spatial ability, that was required for the studies of the Jewish scriptures.

Another argued possibly eugenic practice is that "the “Shadchan,” or marriage broker, may also have played a significant role in Jewish eugenics: [T]he Pentateuch raised Eugenics into a matter of religion . . . The much-despised Shadchan or marriage broker as an institution had many obvious faults. Yet, in a quiet, unscientific manner he has been the means of curing mere sentiment and passion in the matter of mating of sons and daughters of Israel . . . The Shadchan is distinctively on the side of Eugenics in ‘regulating’ the union of men and women".

Abandonment of Judaism

The abandonment of Judaism (apostasy) hypothesis, in addition to abandonment of Judaism discussed above in the eugenics section, points to an ordinance issued in AD 64, by the Jewish High Priest, which required that all Jewish boys should attend school from age six. Within a century, Jews had established in principle universal male literacy and numeracy. The studies, and later participation in religious activities, involved the Jewish scriptures, which are relatively difficult texts. This may have caused those with low intelligence to become discouraged by their constantly and publicly displayed inadequacies and to therefore renounce Judaism. Another possibility is that those involved in occupations such as farming saw these activities as pointless and wasteful. This has been argued to explain a decline in the number of Jews, from 4.5 million in the first century AD to 1.5 million in the sixth century. However, there are several other explanations for this decline, such as a general population decline, one million Jews being killed in Jewish revolts, and forced conversions, although it has been argued that these explanations cannot explain the whole decline.

Also before AD 64, there may have been religious demands, such as knowing the complex laws, that may have caused those with lower intelligence to leave Judaism. Furthermore, the Babylonian exile likely involved only the intellectual elite, while many of those who remained may have been absorbed into other populations, which may have caused the Jewish population after the return of the exiles to have unusually high intelligence.

Occupational discrimination

The occupational discrimination hypothesis argues that Jews in Europe were excluded from certain occupations and therefore were required to work in occupations that often required a high IQ. This hypothesis may also explain the relatively higher mathematical/verbal ability, by this being more important in occupations such as money-lending, tax collection, and import-export trading.

It has been argued that the gene variants that cause several (recessive) genetic diseases that are common among Ashkenazi Jews also increase intelligence for asymptomatic carriers and possibly also for those having the diseases. For example, those who have Gaucher's disease in Israel are six times more likely to be scientists/engineers and twenty times more likely to be physicists. Several of the most common Ashkenazi mutations are argued to have appeared at approximately the same time as the occupational restrictions. However, it has been argued that genetic evidence shows that most, though not all, of these diseases arose from genetic drift after a population bottleneck and show no evidence of selective pressure.

One argument against the theory is that Jews are argued to have already left unskilled occupations and moved into urban skilled occupations well before any occupational restrictions were imposed on them. This is argued to have been caused by their high literacy and numeracy, as argued in the section "Abandonment of Judaism". However, there is disagreement regarding this, with it also being argued that this occupational shift occurred when the occupational restrictions occurred.

Other criticisms include that the occupational mobility is argued to have been limited in the Jewish communities or that intelligence is not the only factor determining success. The latter argument is however a straw man.

The occupational discrimination theory has been argued to be supported by an argued absence of evidence of high Jewish intelligence before the occupational restrictions, apart from the creation of the complex Jewish Bible. This has been disputed with reference to complex Jewish religious writings, such as the Mishnah (2nd century AD) and the Talmuds (4th and 6th century). Also, before the Enlightenment, the vast majority of Jewish scholarship was directed within the Jewish community, rather than at science or philosophy. As a result, Jewish intelligence may not have been apparent to non-Jews. The historical record has been argued to support that Jews were quite successful economically in the ancient world and sought urban occupations requiring education. See also Jewish influence: Antiquity.

Persecution

The persecution hypothesis argues that more intelligent Jews were more likely to survive persecutions, by anticipating these and moving elsewhere, by other countries only accepting Jews with education and required skills, by being better at hiding during persecutions, and by being more able to pay ransoms. This hypothesis may possibly also explain the relatively higher mathematical/verbal ability, by this being more important in order to gain wealth in occupations such as those described in the "Occupational discrimination" section. On the other hand, the most successful would have been the most visible and therefore the most likely to be targeted during persecutions.

An argued problem for this hypothesis is that Gypsies have frequently been persecuted, but have much lower measured IQ than Europeans.

Interbreeding

The interbreeding hypothesis argues that some interbreeding with local populations would affect IQ. It has been argued that this can explain only a minor part of the average Ashkenazi IQ, since it is higher than that of Europeans. However, it may have contributed to raising the Ashkenazi average IQ above the Middle Eastern average. Interbreeding may have been more common among Sephardi and Mizrahi Jews, often with low average IQ populations such as those in North Africa and the Middle East, which is one argued explanation for the lower average IQ of Jews from these regions.

The presence of some limited interbreeding does not imply that a group cannot be genetically distinct. In 2012, a Jewish geneticist argued that Ashkenazi Jews, Sephardi Jews, and Mizrahi Jews are so similar genetically and on other characteristics, and so dissimilar from other groups, that they despite some interbreeding with different groups and some varied characteristics constitute a separate race. On the other hand, Ethiopian Jews are genetically distinct from other Jews, which has been argued to explain their low average measured IQ, which is similar to that of other Sub-Saharan Africans.

Environmental explanations

Environmental explanations include a long cultural history encouraging education and learning, which may possibly raise a person's IQ.

Overall evaluation

Lynn writes that it is difficult to find definite evidence for or against the evolutionary explanations, which are not mutually exclusive. Several or all may have been important. The genetics or not debate is covered in the next section.

Genetics or not debate

The more general debate regarding genetics or not is discussed in the race and intelligence article. There are in addition some specific issues regarding Jews.

Ashkenazi Jews have a very high frequency of myopia, even as 6-year-olds, which makes excessive near work a less likely explanation. Myopia has been suggested to be influenced by the same genes that cause high IQ. (See Health and intelligence).

A study in the US found that 4-6 years old Jewish children in the United States had an IQ of 111, relative to other children. If education was involved in the higher Jewish IQ, then one would expect that their IQ should be lower at this age.

Jewish children with European or Mizrahi parents who were brought up in the same kibbutz, and thus were exposed to a very similar environment, still differed on IQ by approximately the same amount as their parents differed.

External links

Occupational discrimination hypothesis

• Natural History of Ashkenazi Intelligence
• How Jews Became Smart - Anti-"Natural History of Ashkenazi Intelligence"
• Did Discrimination Enhance Intelligence of Jews?
• "Are Jews Smarter?: What Genetic Science Tell Us"
• Are Jews Smarter?
• The evolution of intelligence: The high intelligence of Ashkenazi Jews may be a result of their persecuted past

Other

• Jewish Genius
• Jewish intelligence
• Jews Are a 'Race,' Genes Reveal
• Jewgenics: Jewish intelligence, Jewish genes, and Jewish values
• Jewish Intellectual Supremacism: A Refutation