This is one of the most important topics, right? Well, here is a new and quite thorough paper by Jonathan Schulz, Duman Bahrami-Rad, Jonathan Beauchamp, and Joseph Henrich. Here is the abstract:
Recent research not only confirms the existence of substantial psychological variation around the globe but also highlights the peculiarity of populations that are Western, Educated, Industrialized, Rich and Democratic (WEIRD). We propose that much of this variation arose as people psychologically adapted to differing kin-based institutions—the set of social norms governing descent, marriage, residence and related domains. We further propose that part of the variation in these institutions arose historically from the Catholic Church’s marriage and family policies, which contributed to the dissolution of Europe’s traditional kin-based institutions, leading eventually to the predominance of nuclear families and impersonal institutions. By combining data on 20 psychological outcomes with historical measures of both kinship and Church exposure, we find support for these ideas in a comprehensive array of analyses across countries, among European regions and between individuals with different cultural backgrounds.
As you might expect, a paper like this is fairly qualitative by its nature, and this one will not convince everybody. Who can separate out all those causal pathways? Even in a paper that is basically a short book.
Object all you want, but there is some chance that this is one of the half dozen most important social science and/or history papers ever written. So maybe a few of you should read it.
And the print in the references to the supplementary materials is small, so maybe I missed it, but I don’t think there is any citation to Steve Sailer, who has been pushing a version of this idea for many years.