The WEIRDEST People in the World by Joseph Henrich

[MRM]

Why are some countries rich and others poor? Does it depend on whether you, and your friends, and your grandparents (and their grandparents) married your cousins?

That explanation sounds intuitively incomplete, but Joseph Henrich builds a mountain around it in The Weirdest People in the World. He convincingly argues that Western European (plus North American, or shortened to WEIRD) people have a very different psychological makeup compared to other humans -- both other humans now, and other humans historically -- and those differences help explain the West’s “success”. His more provocative claim is the differences are most explained when, about 1,500 years ago, the Roman Catholic Church banned cousin marriage as part of a larger overhaul of family life.

Did you know Westerns are WEIRD compared to others? Henrich frames his initial beef as one with the misapplication of academic psychology research. Unique human psychology findings from a Western university lab experiment don’t necessarily apply to people born outside of the Western world, and certainly don’t necessarily reflect innate human nature. Consider:

WEIRD (Western Educated Industrialized Rich and Democratic societies) are less likely, in lab experiments, to conform to a group (the Asch Conformity Experiment). Japanese subjects are about 1.6x more likely to conform (than WEIRD ones), Brazilian subjects about 1.7x more likely, and Zimbabweans about 3x more likely.
WEIRD subjects are relatively more patient, measured by willingness to wait for money (think an adult version of the “marshmallow test”). A Swede will forgo $100 now to receive $144 in a year. But globally, the average person requires $189 in a year to give up $100 now, and the far-end of the spectrum (Rwanda) requires $212. (According to Henrich, the figures were adjusted for local currency and purchasing power.)
WEIRD subjects are less likely to lie in dice rolling experiments when lying is anonymous and also gets you more money. (The lying can be measured by an aggregate statistical analysis, i.e., whether higher numbered die were over-reported relative to baseline aggregate probability.)
In a hypothetical prompt, 80-100% of WEIRD subjects believe that their friend has no right to expect them to falsely testify in a trial so that the friend avoids legal punishment. That’s about double the rate of India/China subjects, who are more likely to lie for their friend.
WEIRD subjects are 50%-100% more “analytical” rather than “holistic” in their thinking; for example, in a “triad test”, WEIRD folks would pair a rabbit with a cat (two animals) instead of a rabbit with a carrot (rabbit eats carrot).

Compared to non-WEIRDers, WEIRD people are:

Highly individualistic, self-obsessed, control-oriented, nonconformist, and analytical. We focus on ourselves, our attributes, accomplishments, and aspirations over our relationships and social roles

Henrich’s point is that this isn’t normal; rather, we’re the abnormal (weird) ones.

Henrich emphasizes these are differences, not value judgments, and of course only measured at the population level. Is it a good thing that WEIRD culture has people, on average, more trusting of strangers and less biased towards family members? Of course that depends on your definition of “good”. And also on the current environment/context: In a strong state with a market-oriented economy and rule of law, there’s big payoff (especially collective payoff) in those traits, even if it might be unwise to trust strangers if you find yourself in a different place or different time. It’s understandable that our cultures didn’t uniformly evolve “trust stranger” norms.

II.

So WEIRD people have very different cultures and personalities than others. But why? Henrich’s answer is basically that we got lucky when the Catholic Church decided to ban cousin marriage and embark on a new, and different, family marriage program.

First, a quick example of his overall “cultural evolution” framework. In Henrich’s model, different cultures develop different cultural norms, but within a dynamic process where the culture is also competing with other cultures, resulting in cultural selection pressures (akin to survival of the fittest culture). Henrich recounts an illustrative New Guinea example:

New Guinea villages had a maximum of 300 people, about 80 of which were male. When villages grew larger than that, social ruptures tended to follow -- as though there was an “invisible ceiling” on the scale of human cooperation in New Guinea.
But one community, Ilahita, was an exception. Ilahita had a population of about 2,500.
Anthropologist Donal Tuzin explains the exception by reference to a unique cultural package within Ilahita, largely related to institutionalizing more cross-cleavages within that population. As described, a family might belong to “subgroup A-2”, which meant it interacted with a broader community of other A’s (not all of which were also “2’s”) and interacted with a broader community of other 2’s (not all of which were also “A’s”), meaning the entire community was interconnected, but in a relatively random way. This is intuitively familiar to us moderns, who have our family group, work group, social group, sports team group, etc., in each case with only some overlap. But maybe it was less common in historical human societies. (The anthropologist and Henrich discuss other cohesion mechanisms, like adolescent rituals, that I’m giving short shrift to.)
These cross-cleavages allowed Ilahita to scale to a higher population than other villages that were organized exclusively (or more-so) on family/clan grounds.
Why did Ilahita have these successful customs, such as cross-cleavages, but other villages didn’t? Apparently around 1870 the Ilahita leaders learned and copied some rituals from another successful group (the Abelam), but made errors doing so. Those copying errors turned out to work even better than the original customs, and thus proliferated. An accidental muttation, but one that happened to be useful.

III.

So human history includes culture competition and cultural evolution. Still, as best as we can tell, most of human history was dominated by a “kinship” and clan-based approach to organizing society. Things like who you are, what you do, and who you marry all had a lot to do with your family background and the small community you were born into.

Here are some traits of the familial (or kinship) approach to culture:

Newly married couples set up residence near one person’s (usually groom’s) parents.
Inheritance of property after death is totally familial, usually via your father. (Admittedly inheritance is still mostly familial, but that’s at least an option in modern society.)
“Corporate” (or collectivist) notions of responsibility for each family and clan. “If someone kills someone from your clan (even accidentally) - their entire clan is responsible for paying blood money.” If they don’t, your entire clan is responsible for a revenge killing.
Marriages: Often there are taboos against marrying a sibling. But then norms in favor of marrying a relative like a cousin (or second cousin). Henrich also flags the widespread popularity of “levirate marriage”; if a husband dies, then the wife has to marry one of his brothers or cousin-brothers, in order to maintain the familial link established by the original marriage.

None of the above is in any way universal, tribes everywhere differ, etc., but I take it as a rough picture of relatively common pre-modern practices. Some of these practices are still common today in non-Western places. Pre-Catholic takeover, European tribes mostly reflected the above: Kinship-based units collectively owned territories, provided social identities, adjudicated disputes, provided protection and health care, and arranged marriages. High-status European men married multiple wives.

How about now? 75% of global historical societies studied by anthropologists exhibit marriage to cousins or other relatives, yet WEIRD societies don’t do that. 72% trace lineage through only one parent, while WEIRD societies trace lineage through both parents. WEIRD societies are part of the only 8% of all studied societies with nuclear families, and part of only 5% where newly married couples set up a separate household. Circa year 2020, you can move to NYC for a job and then mate up, and then do whatever you want next (move to the suburbs, move closer to your parents, move closer to her parents, move to California). It’s easy to appreciate how this family freedom is probably historically unique, but is it historically meaningful?

IV.

According to Henrich, it was indeed Christian religious peculiarities, which ultimately impacted family formation, that explain how we got from the traditional kinship culture to our modern Western culture. The first key development was universalizing religions, which include Christianity, Hinduism, Buddhism, and Islam. These universalizing religions had, in certain settings and certain respects, advantages over the previously more common local god approach. They started the path of universal rules or principles that apply to everyone equally. They also tend to believe in contingent afterlives and free will, other factors that prepared the Western world for its cultural evolution.

Really, though, it was the Roman Catholic’s family and marriage program that changed the game.

Henrich’s chart of the Catholic marriage program starts in year 305 when Synod of Elvira forbid men from marrying either (i) a sister of their dead wife or (ii) their daughters-in-law. I don’t know who Synod of Elvira is, or whether he was particularly important, or if such sister-of-dead-wife / daughter-in-law marriages were so frequerent so as to be historically significant. The point is the trend. By year 500-600, first cousin marriage was officially outlawed by Roman Catholic popes and authorities; the Eastern Church, which lagged in both time and intensity of kinship reform, made that official in year 692. The marriage restrictions gradually expanded. By about year 1050, the ban reaches sixth cousins or “marriage with kin as far back as memory goes”. (Aside: In 1983, John Paul II loosened incest restrictions and allowed second cousins and more distant relatives to marry.)

The family and cousin marriage prohibitions forced folks to search further and wider for potential mates:

By roughly 1000 CE, manorial censuses confirm that peasant farming families [in France] lived in small, monogamous nuclear households and had two to four children. Young couples often formed independent neo-local householes, sometimes moving to new manors.

By the late Middle ages, Europeans had later marriage ages (mid-20s), a relatively large percent of unmarried women, smaller families and lower fertility, and frequently worked during a premarital labor period. Henrich contrasts that cultural European landscape to the cultural patterns seen, for example, in China around that time, which still reflected the traditional kinship cultural practices.

Large societal (and, later, psychological) consequences followed the disruption (really deterioration) of Europe’s family culture. Simply put, people intermingled more, and family bonds weakened. Henrich amasses chart after chart to show that we can see current data of strong correlations between personality traits and background family structures. Countries with more cousin marriage and more familial kinship cultures (i.e., non-WEIRD places) are less individualistic, more conformist, more shame-ridden (but fewer feelings of guilty), less trusting of strangers, contribute less in (stranger) group projects, voluntarily donate less blood, etc. (this list could go on for pages).

Henrich also assembles statistical evidence showing a dose-response effect: The longer a population or region was exposed to the Western Church’s marriage family program, “the weaker its families and WEIRDer psychological patterns are today.”

Of course the number of correlations don’t prove Henrich’s theory of causation; it’s possible that European societies had a different secret sauce that propelled them along their path, and that secret sauce (directly or indirectly) causes our modern psychology differences. But his theory is facially plausible. Europeans may have stumbled across a religious mechanism that started weakening familial bonds, gradually at first, but slowly increasing (and resulting in) non-familial bonds, relationships, and institutions like guilds, charter cities, monasteries, universities, and quasi-markets. None of these replacement institutions are particularly impressive or important at first. But they, alongside the unrelenting advance of the marriage program, further contribute to additional weakening of kinship-based institutions. Eventually the quasi-market institutions develop into even more institutionalized markets. The culture and norms encouraged by the new institutions are different from those encouraged by kinship institutions, such as universalizing treatment, positive sum worldviews, fairness towards strangers, and reciprocity. Collectively, they build a sort of interpersonal prosociality. The interpersonal prosociality norms made larger cooperation, and larger urban locations, more viable. These effects continue building on each other; weaker family bonds leading to stronger non-family institutions, leading to larger cities, which in turn further solidify a market approach and weaken family bonds. By about 1200, Belgium, the Netherlands, and Italy started urbanizing; England urbanized later (starting in year 1500), with an overall European urbanization quadrupling (3 percent to 13 percent) from year 800 to 1600. If the industrial revolution represents a fundamental change in the human condition, for Henrich, humanity needed something (anything?) to jump us off the familial relationship track and get us onto the prosocial one. The Catholic church and its family marriage program just happened to be the ticket.

VI.

Henrich points to the WEIRD “clock-time mindset” as one example of the importance of cultural evolution on our psychological differences. WEIRD folks are obsessed with concepts like hourly work efficiency, being “on time”, and not “wasting time.” Henrich argues this is a relatively new psychological development that did not exist before the High Middle Ages. Another fascinating example is the Western legal tradition of investigating “universal legal principes, categories, or axioms from which all specific [laws] could be derived.” According to Henrich, this search for universal legal principles came from an application of WEIRD personality when re-reading Roman case law. It was another mis-copying of sorts, since universal principles did not exist in the Roman legal sources, but Europeans, indoctrinated by hundreds of years of prosociality and universalizing, assumed they must exist.

In Henrich’s telling, Martin Luther’s protestant reformation is perhaps the final booster shot that Europe needed, explaining why Europe (and not others) got modernity, the Enlightenment, the Industrial Revolution, representative government. By this point of the story, things are very cyclical: Europe was simultaneously predisposed to accept something like Protestantism when it came along, and Protestantism further pushed Europe along its developmental path. Relative to Catholicism, Protestantism further individualized our culture and psychology by emphasizing things like reading, self-education, intentions, hard work, and self-discipline. Literacy rates subsequently grew faster in Protestant European countries (such as Britain, Sweden, and the Netherlands) than Catholic European countries (Spain and Italy). If Europe was WEIRD, Protestant Europe became WEIRDer: More individualistic, more rational, less familial, and, later, more Educated, Richer, and Democratic (wEiRD)

By instilling thrift, patience, and an internalized work ethic while at the same time requiring literacy and encouraging schooling, Protestantism had psychologically prepared the rural [European] populace to participate in and fuel the Industrial Revolution. Evidence from the 19th century...shows that compared to Catholicism, early Protestantism fostered higher literacy rates, greater incomes, and more engagement in manufacturing and service industries. Politically, Protestantism probably encouraged the formation of democratic and representative governments.

VII.

According to Henrich, Jared Diamond’s Guns, Germs and Steel explain a lot of dispersion amongst societies and global-level inequality up to about year 1000. But afterwards...

If a team of alien anthropologists had surveyed humanity from orbit in 1000 CE, or even 1200 CE, they would never have guessed that European populations would dominate the globe during the second half of the millennium. Instead, they probably would have bet on China or the Islamic world. What these aliens would have missed...was the quiet formation of a new psychology.

Does Catholicism, family marriage policy, protestantism, and the resulting cultural psychology changes explain Europe’s post-1200 trajectory? Does our propensity to marry our cousin (and that of our great-great-great-etc. grandparents) represent a fundamental break in our history? Henrich’s account seems facially plausible, even if it needs further testing and scrutiny from sociologists, anthropologists, statisticians, and historians. And even if this particular theory is shown invalid, it may still endure by drawing attention to “cultural evolution” and the interplay between cultural institutions and underlying human psychology. Did the European cultural “advances” make Westerners lonelier and sadder while simultaneously richer? Did the human experiment ultimately benefit from the change, or will {nuclear annihilation, global climate change, or AI singularity} ultimately show the folly of breaking down kinship bonds? Henrich doesn’t go there. But such is our luck, good and bad, to be born into the WEIRD lineage. We may eventually realize our psychological approach to the world, just like our physical bodies themselves, resulted from the combination of luck, mutation, and incremental change that underpins most evolved outcomes.

Endnotes:

I should add a global cautionary note that Henrich is often more measured in his conclusions than my summary indicates. For the most part, this isn’t because I disagree with Henrich, but rather want this idea to be easily digested without bogging this summary down with endless qualifications. But also to say that if your primary objection to something is “this seems to be overstating the case”, that’s probably an objection against my summary more than Henrich’s work.
Henrich devotes some pages to discussing polgyamy, arguing that it was probably the natural state of human sexuality and monogamy is deviant. There is already a blog post that Henrich “Gets polygyny wrong.” Although I’m by no means an expert, my understanding of the issue (the prevalence of polygyny v. monogamy in early civilization and pre-civilization) is also softer than Henrich’s, primarily influenced by Sapolsky’s Behave and Geoffrey Miller’s The Mating Mind. https://traditionsofconflict.com/blog/2020/9/8/the-weirdest-people-in-the-world-gets-polygyny-wrong
Why did the Catholic Church care about this kinship marriage stuff, and other religions didn’t? Henrich has some pages on this, although he also seems to treat it as a stochastic event (remember the bit earlier about cultural mutations for the New Guinea tribes). I don't think explaining the origin is actually all that important or central to his argument.