Gregory Cochran, Jason Hardy and Henry Harpending's seminal 2006 paper, "Natural History of Ashkenazi Intelligence" (PDF) is a gift which keeps on giving.
It outlines their case that "the unique demography and sociology of Ashkenazim in medieval Europe selected for intelligence. Ashkenazi literacy, economic specialization, and closure to inward gene flow led to a social environment in which there was high fitness pay-off to intelligence, specifically verbal and mathematical intelligence but not spatial ability."
The Ashkenazim were not the only people doing highly g-loaded work during the 800 years from 800-1600 AD; why were similar pressures not pushing up the IQ of Caucasian elites?
On page 14 we see this:
“It is likely that the selective pressures affecting the medieval Ashkenazi were far stronger [...] because such a high percentage had cognitively demanding jobs, and because the Ashkenazi niche was so specifically demanding of accounting and management skills, while upper classes elsewhere experienced a more diverse set of paths to wealth.What was almost certainly selected for amongst the elites was prosociality (usually conceptualised as Agreeable+ and Conscientious+). The Empathy Quotient seems to be the nearest we have to an instrument measuring this.
“Societies reward different behavioural traits. In some times and places successful warriors and soldiers have had high status, in others merchants, in still others bureaucrats as in ancient China. There were societies in pre-modern Europe in which merchants and businessmen ranked near the top, but this was atypical.
“To the extent that status and wealth were inherited rather than earned, the correlation between cognitive traits and reproductive success in elite groups may have been quite weak. In almost every case elite groups experienced substantial gene flow with other, much larger groups that were not subject to the same selective pressures. This means that the selective pressures experienced by such groups were diluted, spread out into the general population.
“Christian merchants in London or Rotterdam may have experienced selective pressures similar to those of the Ashkenazi Jews, but they intermarried: there was extensive gene flow with the general population, the majority of whom were farmers. The selection pressures experienced by farmers were probably quite different: most likely cognitive skills did not have as high a correlation with income among farmers that they did among individuals whose occupations required extensive symbol manipulation, such as moneylenders, tax farmers, and estate managers.”
Prosociality allows the elite to cohere, to negotiate disagreements in a reasonably harmonious way and to conduct long-term and elaborate cooperative ventures; essential to running complex economies and disparate empires. It also seems evident that there's a prosociality gradient running down the class structure of complex societies - it would be good to see some statistics.
Prosociality generates a specific self-ideology when its tenets are normatively extrapolated to everyone under all circumstances. In this malign form, it surfaces as political correctness - "I can tolerate anything except intolerance".
Maddening though it is, let's not throw the baby out with the bathwater.
Mr Trump, I might be talking about you.
See also my post about elves (!) for more about political correctness and moralising.