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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 IQ of the general white population at 100, which ranges from 107 for Germany to 90 for Turkey according to Richard Lynn's estimates for 2006 [4]. These studies (see references) also indicate that this advantage is primarily in verbal and mathematical performance; spatial and visual-perceptual performance is average. However some statistic data on Israel, which has about 50% of Ashkenazi Jews in its population show that Israel achieves lower average IQ scores than countries of Europe or East Asia (IQ and the Wealth of Nations). (Israel 94, England 100, Hong Kong 107). Israel however is multicultural in nature, where Jews, Muslims (around 1/4 of population) and Christians reside. Besides being controversial, this work relies on existing studies "of questionable validity",[1] leading to results even the authors don't believe to be correct.[citation needed]
| Source | Sample sizes. Number of Ashkenazi Jews tested. | Average IQ Ashkenazi Jews in USA and/or UK |
|---|---|---|
| Backman 1972 | 1236 | 107.8 verbal IQ |
| Backman in present study | 150 | 107.5 crystallized IQ |
| Lynn | Estimated | 103.5 Ashkenazi Jews in Israel |
| Macdonald 1994 | Suggested IQ | 117 |
| Storfer | Suggested IQ | 112 |
| Shuey 1942 | 764 | 1.2 below non-Jewish whites |
| Bachman 1970 | Lesser than 100 | 112.8 |
| Herrnstein/Murray 1994 | 59 | 112.6 |
Cochran et al.
The 2005 study Natural History of Ashkenazi Intelligence[2] 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 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.[3]
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.[4] 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.[5]
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.[4] Many genetically-isolated human groups have faced multifarious adaptive pressures one could cherry pick to justify presently exhibited group traits.[6]
Alternative explanations
- Israeli Ashkenazi's scores may average lower than U.S. and British Ashkenazi, Lynn suggests, due to selective migration effects in relation to those countries, and to immigrants from the former Soviet Bloc countries having posed as Jews to escape poverty. It should be noted that its difficult to classify who is a "Jew" or "Ashkenazi" because of intermixing along family trees. The data isn't necessarily strong enough, however, to rule out identical scores for Ashkenazi across these nations (Malloy (2006)).
- Jews settling in the Rhineland were from the beginning mostly money-lenders and merchants (as well as rabbis). 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 these traditionally high-IQ occupations. This self-selection may also explain why Ashkenazi Jews have significantly higher IQ scores than Mizrahi Jews. 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.
- 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.[7]
- 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.
See also
Notes
- ^ Barnett, Susan M. and Williams, Wendy (2004). "National Intelligence and the Emperor's New Clothes". Contemporary Psychology: APA Review of Books. 49 (4): 389–396. Unknown parameter
|month=ignored (help) - ^ Natural History of Ashkenazi Intelligence
- ^ 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.
- ^ Jump up to: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.
- ^ Patients with torsion dystonia (relatively common in Ashkenazi Jews), for example, are reported to have an average IQ of 122.
- ^ An account of Gould's "just-so" stories critique, especially applicable to the Cochran's speculative sources of Ashkenazi intelligence.[1]
- ^ See the NYTimes coverage for more information.[2] Cochran et al. 2005 is forthcoming in Cambridge's Journal of Biosocial Science. [3]
References
- Cochran, G., Hardy, J., and Harpending, H. (2005). "Natural History of Ashkenazi Intelligence" (PDF). Journal of Biosocial Science (Forthcoming).
- Herrnstein, R.J. & Murray, C. (1994). The Bell Curve: Intelligence and Class Structure in American Life. New York: Free Press.
- 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.
- Murray, Charles (2003). Human Accomplishment: The Pursuit of Excellence in the Arts and Sciences, 800 B.C. to 1950. HarperCollins.
- Storfer, M.D (1990). Intelligence and Giftedness: Contributions of an Early Environment. San Francisco: Jossey-Bass.
External links
- Researchers Say Intelligence and Diseases May Be Linked in Ashkenazic Genes -- from The New York Times
- Did Discrimination Enhance Intelligence of Jews? -- from National Geographic
- "Are Jews Smarter?: What Genetic Science Tell Us" -- from New York Magazine
- The evolution of intelligence: The high intelligence of Ashkenazi Jews may be a result of their persecuted past -- from economist.com
- IQ And Disease: The Curious Case of the Ashkenazi Jews by Steve Sailer, covering a broad perspective on Cochran and his work
- Jewish Genius, an article by Charles Murray in the Commentary magazine
- Jews on Jews: Jews are Great -- Dec. 2005, Seed Magazine.
- The Lessons of the Ashkenazim, an article by Steven Pinker in The New Republic
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