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More on the backwardness of incest

A recent study showed that the medieval Catholic Church’s policy of curbing cousin marriage was instrumental in modernizing the culture and moving beyond nepotism. Now, another study by a researcher at Harvard finds the church’s constraints on incest also contributed to more modern governance: “Already before the year 1500 AD, church exposure and its marriage regulations are predictive of the formation of communes — self-governed cities that put constraints on the executive.”

The study also found that “20th-century cousin marriage rates account for more than 50 percent of the cross-country variation in democracy scores today,” with less cousin marriage leading to more democracy.


Schulz, J., “The Catholic Church, Kin Networks and Institutional Development,” Harvard University (November 2018).

Politically correct hypocrisy

If a man acts like an expert on something, what are the odds that he actually is? What about a woman? Psychologists at Harvard found that, when asked up front, the overwhelming majority of people thought the odds that a man or a woman was actually an expert were the same — judging other people harshly, even at a cost to themselves, for thinking the odds would be different. However, the very same people who made these harsh judgments were themselves guilty of generating unequal odds when asked to construct statistically accurate estimates for similar scenarios.

Cao, J. et al., “People Make the Same Bayesian Judgment They Criticize in Others,” Psychological Science (forthcoming).

Time travel

In a series of experiments, participants were shown a video of a staged bag-snatching crime or were shown a series of words. Then they worked on a puzzle for a few minutes, after which they were randomly assigned to walk a short distance forward or backward, watch a video looking forward or backward from a moving train, or experience no motion at all. Recall for details of the crime video or for words was better after walking backward or watching the backward view from the train. The theory: backward motion seems to evoke time travel, improving recollection.


Aksentijevic, A. et al., “It Takes Me Back: The Mnemonic Time-Travel Effect,” Cognition (January 2019).

Here for the welfare?

Analysis of data on immigration to the welfare states of Northern Europe, Germany, and Canada suggests that people — including those from the developing world — didn’t immigrate for the welfare. Welfare spending rates were not associated with immigration rates, controlling for cost-of-living, demographic, and distance factors. One factor that did increase immigration from a source country was the naturalization rate for previous immigrants from that country.

Ponce, A., “Is Welfare a Magnet for Migration? Examining Universal Welfare Institutions and Migration Flows,” Social Forces (forthcoming).

Kevin Lewis is an Ideas columnist. He can be reached at kevin.lewis.ideas@gmail.com.