Jewish intelligence

Ashkenazi Jews
(יהודי אשכנז Y'hudey Ashkenaz in Ashkenazi Hebrew)
Anne Frank
Total population
10[1]–11.2[2] million
Regions with significant populations
United States United States of America 5–6 million[3]
Israel State of Israel 2.8 million[4][5]
All other countries: About 1.8 million
Languages
Historical: Yiddish, German
Modern: Local languages, primarily: English, Hebrew, Russian
Religion
Judaism, some secular, irreligious
Related ethnic groups
Other Levantines,[6][7][8][9] Samaritans,[8] Assyrians,[8][9] Arabs, Sephardi Jews, Mizrahi Jews etc.

Whether Ashkenazi Jews tend to have higher intelligence than other ethnic groups has been an occasional subject of scientific controversy.

Since the Ashkenazi Jewish population stands at about 10 million[10][11] (or 0.2% of the world population,[12] currently 1 in 550 people), their high IQ scores[13] and relative intellectual success throughout history and in the modern era, as well as their prominence in occupations in the realms of commerce, medicine and finance since the Middle Ages is considered among the most challenging mysteries in Jewish history.[14]

A 2005 scientific paper, "Natural History of Ashkenazi Intelligence",[15] proposed that Ashkenazi Jews as a group inherit higher verbal and mathematical intelligence but lower spatial intelligence than other ethnic groups, on the basis of inherited diseases and the peculiar economic situation of Ashkenazi Jews in medieval Europe. Opposing this hypothesis are explanations for the congenital illnesses in terms of the founder effect, explanations of intellectual successes by reference to Jewish culture's promotion of scholarship and learning, and doubts about whether a group difference in intelligence really exists. However, some believe that the ultimate answer to this question is a combination of both theories, because the two don't exclude each other.[16]

Three years later, an article named "Anti-"Natural History of Ashkenazi Intelligence", written by Brian Ferguson of the Department of Sociology and Anthropology at Rutgers University, attempted to challenge the previous 2005 paper and its hypothesis.[17]

Does a group difference in intelligence exist?

One basic question to be answered in assessing a genetic explanation of unusual intelligence in Ashkenazi Jews is whether today's Ashkenazi Jews really do, as a group, have unusual intelligence. Assessing intelligence, especially of ethnic groups, is notoriously difficult and subject to racial and political biases.

One observational basis for inferring that Ashkenazi Jews have high intelligence is that Ashkenazi Jews rank smartest in world in terms of IQ, with a median of 117, they rank 20% (or 10 points) higher than the global average.[18] Their prevalence in intellectually demanding fields are also disproportionate. While Ashkenazi Jews make up only about 2% of the U.S. population,[15] 27% of United States Nobel prize winners in the 20th century,[15] a quarter of Fields Medal winners,[19] 25% of ACM Turing Award winners,[15] 6 out of the 19 world chess champions, and a quarter of Westinghouse Science Talent Search winners[19] have either full or partial Ashkenazi Jewish ancestry. However, such statistics do not rule out factors other than intelligence, such as institutional biases and social networks, nor should they be read as a percentage to percentage comparison due to the fractional nature of ancestry (e.g. half Ashkenazi).

According to a study performed by Cambridge University, called "From Chance to Choice: Genetic and Justice," Ashkenazi Jews they represent 30% of faculty at elite colleges, 21% of Ivy League students, 25% of the Turing Award winners, 23% of the wealthiest Americans, and 38% of the Oscar-winning film directors. Since 1950, 29% of the Oslo awards have gone to Ashkenazi Jews.[18]

Moreover, in addition there's another fact that brings up the question regarding Ashkenazi Jewish intelligence: Their extremely disproportional "share" in the wealthiest people in the United States as well as other countries (mostly Europeans ones).[20] According to Forbes magazine[21] and multiple other sources, despite being a minority, Jews make up more than 20% percent of the 400 Richest Americans,[22] while some claim that the number is even higher.[23] Overall, Jews make up 10% of the world's total number of billionaires.[24]

A more direct approach is to measure intelligence with psychometric tests. Different studies have found different results, but most have found above-average verbal and mathematical intelligence in Ashkenazi Jews, along with below-average spatial intelligence.[25][26][27] Some studies have found IQ scores amongst Ashkenazi Jews to be a fifth to one full standard deviation above average in mathematical and verbal tests.[28] Studies conducted on British Ashkenazi Jews had similar findings.[29] Another study conducted involving 113 countries found that the average Israeli IQ was 95, ranking 38th on the list,[30] but the IQ of Israeli Ashkenazi Jews (who make up 40% the county's population) yielded a result of 103.[31]

Times magazine's person of the 20th century was Albert Einstein,[32] an Ashkenazi Jew. William James Sidis, who is believed to have had the highest IQ in history, was an Ashkenazi Jew as well. Other disproportionate Ashkenazi Jewish dominated fields include finance, politics, media, Hollywood, and many more.[33]

In his series of books, professor Kevin B. MacDonald proposes that Judaism is a group evolutionary strategy to enhance the ability of Jews to out-compete non-Jews for resources, arguing about the existence of genetic traits among Jews, including above-average verbal intelligence and a strong tendency toward collectivist behavior.

"Natural History of Ashkenazi Intelligence"

"Natural History of Ashkenazi Intelligence",[15] a 2005 paper by Gregory Cochran, Jason Hardy, and Henry Harpending, argued that the unique conditions under which Ashkenazi Jews lived in medieval Europe selected for high verbal and mathematical intelligence but not spatial intelligence. Their argument has four main premises:

  1. Today's Ashkenazi Jews have a higher average mathematical and verbal IQ and an unusual cognitive profile compared to other ethnic groups, including Sephardi and Mizrahi Jews.[34]
  2. From roughly 800 to 1650 CE, Ashkenazi Jews in Europe were a mostly isolated genetic group. When Ashkenazi Jews married non-Jews, they usually left the Jewish community; few non-Jews married into the Jewish community.
  3. During the same period, laws barred Ashkenazi Jews from working most jobs, including farming and crafts, and forced them into finance, management, and international trade. Wealthy Jews had several more children per family than poor Jews. So, genes for cognitive traits such as verbal and mathematical talent, which make a person successful in the few fields where Jews could work, were favored; genes for irrelevant traits, such as spatio-visual abilities, were supported by less selective pressure than in the general population. Furthermore, ostensibly intelligent Rabbis were not barred from reproduction as learned scholars of Christianity were, who were sequestered in monasteries and nunneries.
  4. Today's Ashkenazi Jews suffer from a number of congenital diseases and mutations at higher rates than most other ethnic groups; these include Tay-Sachs, Gaucher's disease, Bloom's syndrome, and Fanconi anemia, and mutations at BRCA1 and BRCA2. These mutations' effects cluster in only a few metabolic pathways, suggesting that they arise from selective pressure rather than genetic drift. One cluster of these diseases affects sphingolipid storage, a secondary effect of which is increased growth of axons and dendrites. At least one of the diseases in this cluster, torsion dystonia, has been found anecdotally to correlate with exceptionally high IQ. Another cluster disrupts DNA repair, an extremely dangerous sort of mutation which is lethal in homozygotes. The authors speculate that these mutations give a cognitive benefit to heterozygotes by reducing inhibitions to neural growth, a benefit that would not outweigh its high costs except in an environment where it was strongly rewarded.

Other scientists gave the paper a mixed reception, ranging from outright dismissal to acknowledgement that the hypothesis might be true and merits further research.[35]

Evolutionary theories for the "Jewish Genius"

In an attempt to find reasons for this phenomenon, many scholars and academics have suggested evolutionary and other accounts.

  • Jewish women would only have children with Jewish males who had high status or wealth.[36]
  • The fact that Jews have been a minority group in most of the places they lived, their community always helped other Jewish fellows, and with collaboration managed to preserve their position and their holdings.[16]
  • Jews were marginalized by pogroms and discrimination, and therefore had to put more effort to survive and be outstanding.[16]
  • Zvi Eckstein and Maristella Botticini present in their book “The Chosen Few" a revolutionary thesis about the development of the Jews’ relative advantage in occupations that necessitated literacy and education: After the destruction of the Second Temple in Jerusalem in 70 C.E., the survival of the Jewish religion demanded that every Jew learn to read and write, and acquire knowledge-acquisition skills; whoever was unable to do so − became assimilated. Thus, out of necessity, the Jews found themselves possessed with skills that proved critical for their economic development.[14]
  • A long cultural history encouraging scholarship and learning;[17]
  • A contribution of talent in the study of Torah to social success in Jewish communities;[37]
  • The enforcement of a religious norm requiring Jewish fathers to educate their sons, whose high cost caused voluntary conversions, explaining a large part of a reduction in the size of the Jewish population;[38] that historic persecution of European Jews fell disproportionately on people of lower intelligence.[35]
  • The encounter with Islam forced the Jews to strengthen the literacy revolution that had taken root centuries earlier and made it more challenging for Arab Jews to integrate in society.[14]

Genetic explanation

Assuming that today there is a statistical difference in intelligence between Ashkenazi Jews and other ethnic groups, there still remains the question of whether the difference is caused by genetic or environmental factors.[17] However, since the two don't contradict each other, some believe the answer is a combination of both.[15]

Researchers have determined that human genes do influence intelligence, saying the percentage of that influence may range anywhere from 40 to 60 percent.[39] Additionally, they concluded, our brain structure and functionality - both biological factors - contribute to our level of intelligence. Using brain imaging, neuroscientists have identified differences in brain structure, specifically differences in our parieto-frontal pathways, that seem to affect our intelligence positively (or negatively, depending on the brain). Well-functioning pathways correlate to better brain functioning, brain efficiency and information processing, which all point to better IQ scores.[40] Therefore, if some genes responsible for one's intelligence do pass through DNA, the same thing must apply to Ashkenazi Jews, suggesting that there's a genetic factor involved.

Another study conducted at the University of Edinburgh found in a genome-wide association study that the g factor to have a genetic basis, however, it was reported that the exact genes behind intelligence have not been discovered yet.[41]

Today, scientists believe in the heritability of IQ, but the subject has been investigated for nearly a century and there is debate about the significance of heritability estimates[42][43] and the mechanisms of inheritance.[44]

Studies of Ashkenazi genes

Most, though not all, of the Ashkenazi congenital diseases arose from genetic drift after a population bottleneck, and show no evidence of selective pressure[45] of the kind called for in the Cochran, et al. paper.[17] For example, the mutation responsible for Tay-Sachs disease arose in the 8th or 9th century, when the Ashkenazi Jewish population in Europe was small, just before they spread throughout Europe. The frequency of this mutation among Ashkenazi Jews today accords with genetic drift starting from a population bottleneck, not with selective pressure favoring its spread.[46]

In contrary to what was thought to be a genetic isolate, some studies found that Ashkenazi Jews have higher European admixture than predicted from previous Y-chromosome analyses.[45] However, other Y-chromosome researches have proven that Ashkenazi Jews did not only have a common Middle Eastern ancestry[47] and were closely related to Middle Eastern and Sephardic Jews, but they are so isolated that on average, all Ashkenazi Jews are genetically as closely related to each other as fourth or fifth cousins.[48] An example of how this isolation is reflected is the existence of Ashkenazi diseases, as well as the fact that "while one in every 800 individuals is susceptible to the BRCA breast cancer gene, one in 40 Ashkenazi Jews test positive for it.[49]

Evolutionary psychologist Steven Pinker suggested that "[t]he most obvious test of a genetic cause of the Ashkenazi advantage would be a cross-adoption study that measured the adult IQ of children with Ashkenazi biological parents and gentile adoptive parents, and vice versa", but noted, "No such study exists, so [Cochran]'s evidence is circumstantial."[50]

In an interview with Gregory Cochran, he said:[39]

"It doesn't have to be extremely heritable for this [intelligence inheritance] to have happened, because you only need small changes in each generation, and there might be forty generations over 1000 year. So if [Ashkenazi Jews] increased a third of an IQ point per generation, that would almost certainly be enough to make this effect happen.

Studies on reproductive advantage

In medieval Ashkenazi society, wealth, social status, and occupation were largely inherited. The wealthy had more children than the poor, but it was difficult for people born into a poor social class to advance or enter a new occupation. Leading families held their positions for centuries.[51] Without upward social mobility, genes for greater talent at calculation or languages would likely have had little effect on reproductive success.[17]

It's not clear that mathematical and verbal talent were the prime factors for success in the occupations to which Jews were limited at the time. Social connections, social acumen, willingness to take risks, and access to capital (through both skill and nepotism) likely played at least as great a role.[17] As these traits are also heritable, the force of natural selection may have been more dispersed than it appears at first glance.

The Talmudic tradition

After the destruction of the Second Temple in 70 CE, Jewish culture replaced its emphasis on ritual with an emphasis on study and scholarship.[52] Unlike the surrounding cultures, most Jews, even farmers,[53] were taught to read and write in childhood. Talmudic scholarship became a leading key to social status.

The emphasis on scholarship came before the Jews turned from agriculture to urban occupations. This suggests that premise #3 of Cochran et al. has the causal direction backward: mastery of written language due to the Talmudic tradition may have made the Jews well suited for financial and managerial occupations at the time when these occupations provided new opportunities. Similar cultural traditions continue to the present day, possibly providing a non-genetic explanation for contemporary Ashkenazi Jews' high IQs and prevalence in intellectual fields.[17]

Of the main factors that together created the Jewish mind, there can be little doubt that the contributon of the age-long preoccupation of the Jew with Talmud and Halachah is formidable. The study of Talmud, undertaken at an early age and pursued assiduously, nurtured alertness, discernment, and acumen and cultured the ability to weigh situations and opinions. It encouraged debate and individual research, rewarded initiative, and lauded brilliance.[54] - The Study of Talmud, Jason Aronson Inc, 1996

See also

Further reading

  • University of Utah.
  • Richard Lynn. The Chosen People: A Study of Jewish Intelligence and Achievement. Washington Summit Publishers, 2011.
  • Ferguson, R. Brian, How Jews Become Smart: Anti-"Natural History of Ashkenazi Intelligence"
  • Lynn, R. and Longley, D. (2006). "On the high intelligence and cognitive achievements of Jews in Britain." Intelligence, 34, 541–547.
  • MacDonald, K. (1994). A People That Shall Dwell Alone. Westport, CT: Praeger.

External links

  • National Geographic
  • "Are Jews Smarter?: What Genetic Science Tell Us", New York Magazine
  • The evolution of intelligence: The high intelligence of Ashkenazi Jews may be a result of their persecuted past, economist.com
  • Commentary magazine
  • Slate
  • Haslinger, Kiryn. Scientific American, 21 September 2005.

References

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