Ashkenazi intelligence

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Ashkenazi intelligence is the conjecture that the higher general intelligence measured in IQ tests of Ashkenazi Jews results from natural selection to extended urban living and historical persecution in Europe. Physicist Cochran and anthropologists Hardy and Harpending from the University of Utah advanced the conjecture in a 2006 paper.[1] Brian Fergueson of Rutgers University published a critique of the paper in 2008 showing many points of improbability and concluding that the conjecture is highly unlikely.[2]

Contents

[edit] Psychometric findings

Certain psychometric studies have recorded people of Jewish background[clarification needed] as scoring higher than average on various tests,[1][3] with estimates ranging from 3 to 12 points above the mean of white gentiles, whose score is generally normalized to 100. These studies (see references) also indicate that this advantage is primarily in verbal and mathematical performance; spatial and visual-perceptual performance is average. The authors argue that these finding are supported by Ashkenazi academic achievement, noting that while, for example, in the United States, Ashkenazi Jews represent less than 2% of the population, they have have won 27% of the US Nobel Prizes in science.[1] However, IQ studies and their findings have been characterized by psychologists Susan Barnett and Wendy Williams as relying on existing studies "of questionable validity" in an APA review article.[4]

Some statistical data on Israel, where up to 38% of its population is composed of Ashkenazi immigrants from Europe or their descendants,[citation needed] shows that Israel achieves lower average IQ scores than some of the countries of Europe or East Asia.[5] Israel, however, is a multiethnic society (where less than 38% of the national population have any Ashkenazi descent),[6] with not only Jews of diverse ethnic backgrounds, but also a sizable (over 20 percent) non-Jewish population.



Source Sample sizes. Estimated IQ of group
Backman 1972[7] 1236 eighteen year olds Verbal Knowledge 107.8, English Language 99.5, Mathematics 109.7, Visual Reasoning 91.3, Perceptual Speed and Accuracy 102.2, Memory 95.1
Storfer 1990 Suggested IQ 112
Herrnstein/Murray 1994 98 112.6, American Jews, from the NLSY
Lynn 2006[citation needed] Estimated 103.5 Ashkenazi Jews in Israel

[edit] Cochran et al.

The 2005 study Natural History of Ashkenazi Intelligence[1] by Gregory Cochran, Jason Hardy, and Henry Harpending at the University of Utah noted that European Jews were forbidden to work in many of the common jobs of the Middle Ages from 800 to 1700 CE, such as agriculture, and subsequently worked in high proportion in professions such as finance and trade, some of which were forbidden to non-Jews by the church. Those who performed better are known to have raised more children to adulthood, according to Cochran et al., passing on their genes in greater proportion than those who performed less successfully.[8]

Cochran et al. hypothesized that the eugenic pressure was strong enough that mutations creating higher intelligence when inherited from one parent but creating disease when inherited from both parents would still be selected for, which could explain the unusual pattern of genetic diseases found in the Ashkenazi population, such as Tay-Sachs, Canavan disease, Gaucher's disease, Niemann-Pick disease, Mucolipidosis type IV, and other lipid storage disorders and sphingolipid diseases.[9] Some of these diseases (especially torsion dystonia) have been shown to correlate with high intelligence, and others are known to cause neurons to grow an increased number of connections to neighboring neurons.[10]

The New York Times described a mixed scholarly reaction to the Harpending paper. While some, such as Steven Pinker, were intrigued by the conjecture, several felt that the level of proof was lacking. In addition, several raised the possibility of a "founder effect" rather than natural selection being the rationale for the genetic diseases (in disagreement with the paper which dismissed that possibility as statistically unlikely.)[9]

Jon Entine published Abraham's Children: Race, Identity and the DNA of the Chosen People in 2007 - his book, which was favorably reviewed by Nature Genetics, reviews studies that show that Ashkenazi Jews test out to have a higher IQ on average than many other population groups.

[edit] Other theories

[edit] Environmental

  • Persecution led Jews to embrace education as a transportable asset, to better adapt to novel surroundings.[1]
  • Jews settling in the Rhineland were from the beginning mostly moneylenders and merchants, as well as rabbis.[citation needed] A biological (hereditary) explanation for high Ashkenazi IQ may be that modern Ashkenazi Jews are descended mostly from the several thousand Jewish settlers that belonged to occupations that one author claims are "far more highly selected for intelligence."[citation needed] An environmental (cultural) explanation for high Ashkenazi IQ is that since it was forbidden for Christians to take interest and money-lending, Jews took the opportunity and developed into a relatively wealthy social group, which traditionally can afford higher education to their children. The extent to which intelligence is hereditary (determined by genes) remains a controversial subject.[2]

[edit] Genetic

  • Talent in the study of Torah traditionally contributed to one's social success in Jewish communities; those more lacking in the capacity for such study were perhaps more prone to assimilate into general culture, thereby raising the average intelligence of the given Ashkenazi community. (Murray 2003)
  • European Jews' history of persecution selected for high intelligence, leaving a positive effect on the hereditary component of their IQ.[11]

[edit] See also

[edit] Notes

  1. ^ a b c d G. Cochran, J. Hardy, H. Harpending, Natural History of Ashkenazi Intelligence, Journal of Biosocial Science 38 (5), pp. 659–693 (2006).
  2. ^ http://andromeda.rutgers.edu/~socant/How%20Jews%20Became%20Smart%20(2008).pdf
  3. ^ Richard J. Herrnstein, Charles A. Murray, The bell curve: intelligence and class structure in American life, (NY 1996)
  4. ^ Barnett, Susan M. and Williams, Wendy (August 2004). "National Intelligence and the Emperor's New Clothes". Contemporary Psychology: APA Review of Books 49 (4): 389–396. http://psycinfo.apa.org/psyccritiques/display/?uid=2004-17780-001. 
  5. ^ Lynn, R. and Vanhanen, T. (2002). IQ and the wealth of nations. Westport, CT: Praeger. ISBN 0-275-97510-X
  6. ^ http://www.cbs.gov.il/reader/
  7. ^ Backman, M.E. (1972) Patterns of mental abilities: ethnic, socioeconomic and sex differences. American Educational Research Journal, 9,1-12.
  8. ^ The Jews rarely married outside of their faith, creating a reproductively isolated population in which, in the statistical models of Cochran and his co-authors, this pressure would be able to influence gene frequency over nine centuries and 35 generations.
  9. ^ a b Wade, Nicholas. Researchers Say Intelligence and Diseases May Be Linked in Ashkenazic Genes, The New York Times, June 3, 2005. Retrieved February 12, 2007.
  10. ^ Patients with torsion dystonia (relatively common in Ashkenazi Jews), for example, are reported to have an average IQ of 122.
  11. ^ See the NYTimes coverage for more information

[edit] References

[edit] External links

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