Ashkenazi Jews are the most intelligent ethnic group in the world, in large part due to their propensity for deadly genetic diseases, according to a pair of American professors.
Published earlier this year, The 10,000 Year Explosion details new and controversial theories on human evolution set forth by Professors Gregory Cochran and Henry Harpending, two anthropology professors at the University of Utah. While most evolutionary theorists say humanity has reached an evolutionary plateau, Cochran and Harpending assert that humanity continues to evolve today, and at a more accelerated rate than in the past.
To exemplify their theory, Cohran and Harpending – neither of whom is Jewish - set out to explain the unusually high IQs of Ashkenazi Jews, Jews of European descent.
While the average IQ of Europeans is 100, the average Jew of European descent earns an IQ score of 107.5 to 115, making an Ashkenazi Jew almost 6 times as likely to be a genius as a non-Jewish European. In a 2005 paper published by Cochran and Harpending entitled "Natural History of Ashkenazi Intelligence", the pair notes "During the 20th century, [Jews] made up about 3% of the US population but won 27% of the US Nobel science prizes and 25% of the ACM Turing awards. They account for more than half of world chess champions."
The professors claim Ashkenazi intelligence results from three factors: historically low levels of intermarriage, Medieval social and political persecution which forced Ashkenazi Jews out of common jobs and into intelligence-based work, resulting in higher levels of procreation for successful Jews, and a propensity to be afflicted by diseases affecting the processing of sphingolipids, the fat molecules that transmit nerve signals.
Ashkenazi Jews are disproportionately afflicted by several lethal disorders including Tay-Sachs, a debilitating and fatal neurological disorder with a life expectancy of 4 years, the brain disease Canavan, with a life expectancy of 5, Gaucher's disease, in which fats accumulate in the spleen, liver, bone marrow, lungs, and even brain, and Niemann-Pick disease Type A, in which babies accumulate fatal fatty tissue in various organs, leading to profound brain damage and death before the age of 2.
Cochran and Harpending believe this is due to heterozygote advantage -- where having two copies of a mutated gene causes serious health problems, but having one copy actually causes positive health effects.
A recent article on the new book by the Los Angeles Times cited a famous example of heterozygote advantage occurring among people of African descent. Those with two mutated hemoglobin B genes develop debilitating sickle cell anemia, while those with one bad gene make blood cells only slightly deformed, but in such a way as to continue to be useful while also making them immune to malaria.
According to the scientists, this theory extends itself to Ashkenazi Jews in that with two mutated genes, they develop deadly sphingolipid-related diseases, but with one, increased intelligence resulting from the increase of compounds which also promote the growth and branching of nerve fibers.
Though many of the "Jewish diseases" are fatal, they continued to be passed down through the generations because of the high value and attractiveness of intelligence in Jewish culture, leading those possessing the mutant genes to marry and reproduce before being cut down by disease, according to the scientists.
Cochran says his affirmation of the intelligence of Ashkenazi Jews will continue to be controversial due to society's discomfort with labeling one ethnic group smarter than others, even though society has already accepted that some groups are taller, shorter, or faster.