A new paper suggests that changes to family life prompted by medieval Catholicism played a large role in fostering individualism in the West. The Washington Post‘s write-up explains it thus:
Catholic Church teachings disrupted [extended kinship] networks, in large part by prohibiting marriage between relatives (which had been de rigueur), and eventually provoked a wholesale transformation of communities, changing the norm from large clans into small, monogamous nuclear families.
That cultural overhaul, the researchers argue, prompted tremendous changes to human psychology.
The research might be particularly interesting in light of recent arguments that John Locke and the Founding are responsible for planting the seeds of an excessive individualism in our culture.