Ashkenazi intelligence

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Ashkenazi intelligence refers to the general intelligence of Ashkenazi Jews, the Jews of Central and Eastern European origin who are the descendants of Jews who settled in the Rhineland beginning about the year 800 CE.

Contents

[edit] Psychometric Findings

Psychometrics research has found that Ashkenazi Jews have the highest mean score of any ethnic group on standardized tests of general intelligence, with estimates ranging from 7 to 17 points above the mean of the general white population. [1][2][3][4][5][6] These studies also indicate that this advantage is primarily in verbal and mathematical performance; spatial performance is the same as the general white average, 103. However statistic data on Israel, which have largest percentage of Ashkenazi Jews in its population (about 50%) (http://en.wikipedia.org/wiki/IQ_and_the_Wealth_of_Nations) shows that Israel achieves much lower average IQ score than any country of Nothern Europe or East Asia. (Israel 94, England 100, Hong Kong 107).

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[edit] Achievement

Ashkenazi Jews have made disproportionately large contributions to presumably intellectual pursuits. Though they are about a quarter of a percent of the world's population, they comprise 28 percent of Nobel Prize winners in Physics, Chemistry, Physiology or Medicine, and Economics, and have accounted for more than half of world chess champions.[4] In the United States, Ashkenazi Jews represent less than 2 percent of the population, but have won 40 percent of the Nobel Prizes in science awarded to U.S. citizens, and 25 percent of all Turing Awards. A significant decline in the number of Nobel Prizes awarded to Europeans and a corresponding increase in the number of prizes awarded to U.S. citizens occurred while Nazi persecution of Jews drove them from Europe during the 1930s and drastically reduced their numbers in Europe in the 1940s.[5]

Whether these differences may be attributed entirely to environmental factors or partially to genetic factors is not quite settled, reflecting the larger academic debate on group differences in intelligence.

[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 C.E. 800 to 1700, such as agriculture, and subsequently worked in high proportion in meritocratic jobs requiring higher intelligence, such as finance and trade, some of which were forbidden to gentiles 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.[2]

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, Gaucher's disease, Niemann-Pick disease, Mucolipidosis type IV, and other lipid storage disorders and sphingolipid diseases.[3] 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.[4]

Reviews of the controversial paper have been both positive and negative, with critics claiming the argument to be far-fetched and unsupported by direct evidence.[3] Many genetically-isolated human groups have faced multifarious adaptive pressures one could cherry pick to justify presently exhibited group traits.[5] Supporters of the paper, however, saw the critique as an example of scientifically-justified prejudice.

[edit] Alternative Explanations

  • 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 community.(Murray 2003, Shafran 2005)
  • Among the devout, daily study of the Talmud was required and respected. Those who left the fold of Orthodoxy replaced daily Torah study with rigorous secular scholarship.
  • The affluent tended to be more intelligent and fertile, as well as educated, propagating higher intelligence and a greater reverence for scholarship. A Torah scholar would often marry the daughter of an affluent merchant in exchange for the latter's extended financial support for the scholar's studies.
  • European Jews' history of persecution selected for high intelligence, leaving a positive effect on the hereditary component of their IQ.[6]
  • Persecution led Jews to embrace education as a transportable asset, to better adapt to novel surroundings.
  • Jews reached a population bottleneck in the 14th Century at the height of the Black Death when they were widely blamed for the plague. This small population allowed a few random genetic changes (genetic drift) to take root as they could not do so in a larger population that resists drift.

[edit] See also

[edit] Notes

  1. ^ Natural History of Ashkenazi Intelligence
  2. ^ 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.
  3. ^ 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.
  4. ^ Patients with torsion dystonia (relatively common in Ashkenazi Jews), for example, are reported to have an average IQ of 122.
  5. ^ An account of Gould's "just-so" stories critique, especially applicable to the Cochran's speculative sources of Ashkenazi intelligence.[1]
  6. ^ See the NYTimes coverage for more information.[2] Cochran et al. 2005 is forthcoming in Cambridge's Journal of Biosocial Science. [3]

[edit] References

1. Cochran, G., Hardy, J., and Harpending, H. (2005). "Natural History of Ashkenazi Intelligence" (PDF). Journal of Biosocial Science (Forthcoming).

2. Herrnstein, R.J. & Murray, C. (1994). The Bell Curve: Intelligence and Class Structure in American Life. New York: Free Press.

3. Lynn, R. and Longley, D. (2006). "On the high intelligence and cognitive achievements of Jews in Britain." Intelligence, 34, 541-547.

4. MacDonald, K. (1994). A People That Shall Dwell Alone. Westport, CT: Praeger.

5. Murray, Charles (2003). Human Accomplishment: The Pursuit of Excellence in the Arts and Sciences, 800 B.C. to 1950. HarperCollins.

6. Storfer, M.D (1990). Intelligence and Giftedness: Contributions of an Early Environment. San Francisco: Jossey-Bass.

[edit] External links

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