Gregory Cochran

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Gregory Cochran
Born Gregory M. Cochran
1953 (age 63–64)
Citizenship American
Fields Physics, Anthropology
Institutions University of Utah
Alma mater University of Illinois at Urbana–Champaign
Known for The 10,000 Year Explosion

Gregory M. Cochran (born 1953) is a physicist, and research associate at the anthropology department at the University of Utah,[1] known for hypotheses in evolutionary medicine and genetic anthropology. He argues that cultural innovation resulted in new and constantly shifting selection pressures for genetic change, thereby accelerating human evolution. He is co-author of the book The 10,000 Year Explosion.

Human evolution[edit]

In opposition to what he sees as the 'conventional wisdom' that civilization has been a static environment which imposed stabilizing selection on humans, Cochran, along with like minded anthropologists such as John D. Hawks,[2] contends that haplotype and other data indicate the selection of genes has been strongest since the advent of farming and civilization.[3]

Ashkenazi intelligence[edit]

Cochran and co-authors Jason Hardy and Henry Harpending suggest that the widely observed high average IQ of Ashkenazi Jews may be attributed to natural selection for intelligence during the Middle Ages and a low rate of genetic inflow. Cochran et al. hypothesise that the occupational profile of the Jewish community in medieval Europe had resulted in selection pressure for mutations that increase intelligence, but can also result in hereditary neurological disorders.[4][5]

Infectious causation[edit]

Along with Paul W. Ewald, Cochran believes an evolutionary perspective suggests that common diseases are caused by pathogens. In a paper they point to a history of common diseases, once thought to be due to noninfectious environmental factors, being found to have an infectious origin;[6] for example, peptic ulcers, once thought to occur because of stress, are now believed to often be caused by the pathogenic bacteria Helicobacter pylori. The association of human papilloma virus with cervical cancer is another example. Cochran and Ewald propose that Koch's postulates are difficult to fulfill for the still unproven cases of infectious causation because of the focus on identifying the infectious agent which is often highly cryptic.


A related hypothesis is that the proximal cause of homosexuality must be an infection.[7][8] Cochran does not suggest that an infectious agent that causes homosexuality is spread by homosexuals. The premise is that homosexuality reduces the number of offspring and would lead to the genes carried by a homosexual person to be progressively eliminated over generations. Cochran maintains that the observed level of prevalence of exclusive homosexuality (3 to 4 percent of men and 1 to 2 percent of women in the United States) means genes cannot be the cause of homosexuality. This argument is based on natural selection, the fitness cost of genes 'for' homosexuality being too great for its occurrence at a frequency above that of random mutation (~ 1 in 50,000). The argument assumes that evolution would have largely eliminated homosexuality related to non-infectious environmental causes, except novel ones.[9]


  1. ^ "Archived copy". Archived from the original on 2016-08-17. Retrieved 2016-07-21. 
  2. ^ Phelan, Benjamin (October 2008). "How We Evolve". Seed Magazine. pp. 66–73. Retrieved September 12, 2015. 
  3. ^ Gregory Cochran; Henry Harpending (2009). "Overview: Conventional Wisdom". The 10,000 Year Explosion: How Civilization Accelerated Human Evolution. Basic Books. pp. 1–25. ISBN 0-4650-0221-8. 
  4. ^ Kaplan, Karen (April 18, 2009). "Jewish legacy inscribed on genes?". Los Angeles Times. Retrieved November 5, 2015. 
  5. ^ Cochran, Gregory; Hardy, Jason; Harpending, Henry (2005). "Natural History Of Ashkenazi Intelligence" (PDF). Journal of Biosocial Science. 38 (05): 659–93. doi:10.1017/S0021932005027069. ISSN 0021-9320. PMID 16867211. 
  6. ^ Cochran, Gregory M; Ewald, Paul W; Cochran, Kyle D (2000). "Infectious Causation of Disease: An Evolutionary Perspective" (PDF). Perspectives in Biology and Medicine. 43 (3): 406–448. doi:10.1353/pbm.2000.0016. ISSN 1529-8795. PMID 10893730. 
  7. ^ Cochran, Gregory. "An Evolutionary Look at Human Homosexuality". Archived from the original on 11 October 2008. Retrieved September 12, 2015. 
  8. ^ "Cause of Homosexuality: Gene or Virus?". 2005. Retrieved September 12, 2015. [dead link]
  9. ^ Hopper, Judith (February 1998). "A New Germ Theory (Part Two)". The Atlantic Monthly. pp. 41–53. Retrieved September 12, 2015. 

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