Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past

by David Reich

It is tempting to argue that genetic influence on bodily dimensions is one thing, but that cognitive and behavioral traits are another. But this line has already been crossed. Often when a person participates in a genetic study of a disease, he or she fills out a form providing information on height, weight, and number of years of education. By compiling the information on the number of years of education for over four hundred thousand people of European ancestry whose genomes have been surveyed in the course of various disease studies, Daniel Benjamin and colleagues identified seventy-four genetic variations each of which has overwhelming evidence of being more common in people with more years of education than in people with fewer years even after controlling for such possibly confounding factors as heterogeneity in the study population.25 Benjamin and colleagues also showed that the power of genetics to predict number of years of education is far from trivial, even though social influences surely have a greater average influence on this behavior than genetics. They showed that in the European ancestry population in which they carried out their study, it should be possible to build a genetic predictor in which the probability of completing twelve years of education is 96 percent for the twentieth of people with the highest prediction compared to 37 percent for the lowest.