It’s early, but The WEIRDest People in the World: How the West Became Psychologically Peculiar and Particularly Prosperous by Joseph Henrich will likely be one of the new decade’s most influential books. Henrich complements work by Joshua Greene, Richard Wrangham, Jonathan Haidt, Steven Pinker, Michael Shermer, and others on the psychological underpinnings of modern liberalism—liberalism in the more-or-less original sense of the word.
Henrich’s book has two main arguments. One is historical: The Catholic church, completely unintentionally, set off a social chain reaction that created modernity. The second is psychological: People in modern societies are psychologically distinct than people from traditional kin-based societies.
He uses the acronym WEIRD for Western, Educated, Industrialized, Rich, and Democratic, to describe the unusual people in modern market-liberal societies. If you are reading this book review, then you are probably WEIRD, and so is nearly everyone you know. But we WEIRD people are the outliers in human history. Outside of Europe, East Asia, and North America, there are very few of us.
Most human societies are built on kin-based structures. This was true during our hunter-gatherer past, which was about 190,000 years of our 200,000-year history—95 percent of our species’ time on Earth. Societies remained kin-based through the agricultural revolution, and through the birth of cities about 6,000 years ago. And it is still true today in most countries. Despite occasional flowerings, such as the Song dynasty China and the Dutch Golden Age, there were no enduring WEIRD societies in human history until about two centuries ago. This is maybe one tenth of one percent of human existence, and even then, most societies today are still kin-based. Again, it is WEIRD people who are unusual.
What is a kin-based society? In these, business partnerships, social networks, and marriages are confined to networks that rarely stray outside the extended family or clan. People tend to be wary of non-kin, and have a strong in-group-vs.-out-group worldview. People tend to look out for their clan’s collective interest over their individual interest. In kin-based societies, nepotism isn’t frowned upon; it’s the norm. WEIRD Americans today look askance when a president appoints inexperienced family members to be senior advisers. But in most other societies, this would have been acceptable, even normal behavior.
By contrast, WEIRD people are more individualistic and more trusting of outsiders. Kin-based families often arrange marriages for their children. WEIRD people usually marry for love. Kin-based people are expected to enter the family business. This is why so many of us have occupation-based surnames, such as Smith, Baker, or Fisher. WEIRD people usually prefer to choose their own line of work, which is one reason why today’s Smiths, Bakers, and Fishers rarely practice those occupations.
Kin-based people are reluctant to do business with strangers and foreigners. WEIRD people are more open to trade and more trusting of potential business partners they have never met. Nobody is purely meritocratic, but WEIRD people are closer to that end of the spectrum than most people.
So now that we know the difference between most people and WEIRD people, what is Henrich’s historical argument about the Catholic church accidentally making today’s WEIRD-ness possible?
The Catholic church blew up traditional kin networks through what Henrich calls its unofficial “Marriage and Family Program (MFP).” In short, the Church prohibited cousin marriages. The incest taboo is a human universal. But its boundaries vary from place to place. The church decided to push them progressively further out over a period of centuries. In many places, it eventually prohibited marriages closer than second and third cousins. In a few places it briefly went as far as eighth cousins.
This was a bigger deal than it sounds. Back in, say, the 12th century, people lived isolated lives. Few people lived in cities. Many people lived their entire lives within a 30-mile radius. They met few, if any, people outside of their extended families. And the wanderers they did meet were often beggars, vagrants, or outlaws. The Church’s MFP forced these isolated people to look outside their villages and kin groups for marriage partners. This forced openness, in the long run, ended up wiring people’s brains differently.
Young people are impressionable. When they are of marriageable age and are forced to meet and interact with strangers, and travel among them, traditional closed-kin psychological barriers gradually break down. They are gradually replaced with growing degrees of WEIRDness. It is a long, gradual process with many degrees. But over centuries, the effects add up.
None of the changes Henrich describes are genetic. None of them are racial, and none of them are peculiar to Europe. The conditions that make individuals WEIRD are cultural, intellectual, and psychological.
Using cousin marriage rates as a stand-in for how strong the Church’s Marriage and Family Program operated in different regions, along with historical records, Henrich finds that the MFP was the single biggest cause of everything from per capita GDP to interest rates to murder rates. Interestingly, regional cousin marriage rates closely track religious divisions and regional church influences. Henrich himself was skeptical about the MFP’s cultural influence, so he checked his results every way he could.
So, while openness is the real engine of WEIRDness, in Europe’s case, Church doctrine was what drove the process of opening up.
The differences between kin-based and WEIRD people show up in psychological tests. The Church’s MFP turns out to have changed people’s personalities and psychological profiles. In my recent review of Virgil Storr and Ginny Choi’s excellent Do Markets Corrupt Our Morals?, I noted their finding that people from market societies play decision-making games differently than do people from non-market societies. Henrich argues that this is because they are psychologically different.
From birth, WEIRD people from market societies have been more exposed to outsiders and more likely to trust them. No wonder they tend to play lab games that way. They tend to be more trusting of other players and more willing to use long-term strategies. People from kin-based societies are more likely to do the equivalent of a dine-and-dash from a restaurant. If the other player is not from their in-group, they feel fewer compunctions about cheating that other player.
Kin-based and WEIRD people even assign blame differently. Most WEIRD people see classroom teachers’ disciplinary tactic of punishing an entire class for one student’s offense to be morally wrong. Kin-based people see this as normal, and are fine with it. They think more in terms of collective responsibility than individual responsibility. In fact, criminal justice systems in many kin-based societies punish whole families for one member’s crime.
There is a reason for this. In most human societies, life was precarious. One bad harvest could mean starvation. Very strong conformity norms were a survival advantage. Collective punishment helps to reinforce conformity norms. Maybe someone does have a new idea for planting a crop differently. But if it fails, the stakes are life and death. It’s probably not worth it. Better to make sure that everyone sticks with what he or she knows works.
When most people’s only experience with foreigners is with either castoffs or invading armies, they probably aren’t going to trust them. They’d probably return the favor when possible. While trade is a positive-sum interaction, theft and war are zero-sum at best. When people’s main experience with out-groups is negative or zero-sum, they are less likely to trade with foreigners and realize the benefits of division of labor. Safer to do it all yourself.
Henrich has written a provocative book that builds on an already robust literature. Despite its deep historical and psychological content, The WEIRDest People in the World is also highly relevant to modern public policy. The regulations and legislation that groups like CEI deal with on a daily basis do not come from a vacuum. They come from longstanding political institutions. And these system-level institutions in turn come from culture. All three of those levels matter. A reformer who works on only one of them will fail. Henrich has come up with a plausible framework to explain how they interact over the long run, and how they can shift. Where people are relatively WEIRD, people will build relatively market-oriented political institutions—and eventually, policies. Where they are kin-based, they probably won’t.
Without the Church’s unofficial Marriage and Family Plan, European culture likely would have remained insular and kin-based. That tendency still exists, and is expressing itself in the European Union’s trending towards becoming a protectionist trading bloc. Reformers need to push back and remind people that WEIRD-style openness has massive benefits, especially for the poor.
What about the rest of the world? Fortunately, the Church’s MFP is not the one and only way for people to become psychologically WEIRD. Ideas can be imported and exported, same as goods and services. America was a relatively WEIRD society from the start, as was Australia. The Asian tigers such as Japan, Korea, Singapore, and Hong Kong, saw the economic success of WEIRD countries, and followed their example. China is at a midway point psychologically, and its institutions are still extractive and kin-based by WEIRD standards. This may limit China’s future growth as a global power.
The point is that setting a good example can do a lot more good than people think. This puts today’s nationalists and economic protectionists in an awkward position. They are not the future. They are throwbacks to an impoverished, unhappy past.
The post-1800 Great Enrichment that billions of people are enjoying today has deep and distant causes operating at multiple levels. Henrich’s thesis of WEIRD psychology, cultural openness, and economic prosperity will have a major impact on future work in geopolitics, economic development, political polling, immigration, and free trade for a long time to come.
(This post was updated on September 14, 2021.)