• [E]conomists and psychologists studying Western samples have simply assumed for decades that they were measuring a feature of our species’ psychology rather than a local cognitive calibration to society’s institutions, languages, and technologies.
  • —Joseph Henrich, The WEIRDest People in the World1 (page 389)

The latest book by Joseph Henrich is the most ambitious analysis of social behavior that I have ever read. It attempts to cover essentially all human history and the entire spectrum of different societies, using the full range of disciplines of social science. To offer a review is difficult, and to attempt a summary is impossible.

At the center of the book are the traits that Henrich describes using the acronym WEIRD: Western, Educated, Industrialized, Rich, and Democratic, referring to the cultures of certain societies. Over a decade ago, Henrich and colleagues came to the realization that many findings in psychology and behavioral economics that were based on studies of people living in WEIRD cultures did not replicate when attempted in other cultures.

One of Henrich’s central theses is that culture affects psychology, particularly when cultural institutions persist over many generations. For me, this raises a question: What makes a trait a psychological trait, as opposed to a cultural trait? Intuitively, I would say that if it is a trait that you would have regardless of the culture in which you are raised, then it is a psychological trait. But if a trait is mostly determined by the culture in which you are raised, then it is a cultural trait. Still, for me the distinction between psychological traits and cultural traits seems blurry, so I will describe traits as psychological/cultural, or PC.

The opposite of WEIRD PC is kinship or clan PC. In kinship PC, what knits a society together are familial interconnections, including many marriages among close relatives.

Figure 14.1, on page 473, offers a summary of the key ideas in the book. Here I will present a few points based on that figure.

  • 1. All societies were kinship cultures until[B]etween about 400 and 1200 CE, the intensive kin-based institutions of many European tribal populations were slowly degraded, dismantled, and eventually demolished by the branch of Christianity that evolved into the Roman Catholic Church (page 158)
  • 2. The Church instituted rules about marriage and children that made kinship societies unsustainable. Most notably, forbidding marriage among cousins and other relatives meant that a clan would die out unless its members married outside of the clan.
  • 3. Weakening kinship relationships led to people becoming more individualistic and less dependent on their clans.National populations that collectively experienced longer durations under the Western Church tend to be (A) less tightly bound by norms, (B) less conformist (C) less enamored with tradition, (D) more individualistic, (E) less distrustful of strangers, (F) stronger on universalistic morality, (G) more cooperative in new groups with strangers, (H) more responsive to third-party punishment… and (L) more analytically minded. (page 227)

These PC traits enabled some Europeans to adapt to markets, cities, and voluntary associations.

  • 4. These impersonal institutions in turn promoted the development of PC traits that made people better able to cooperate with strangers and less inclined to favor kin. People became more patient, more concerned with efficient use of time, and more inclined to locate characteristics in an individual. These PC traits in turn adapted people for representative government, our concept of the rule of law, and innovation and economic growth.

With those main themes sketched out, let me turn to some interesting tidbits.

  • Compared to farmers and herders who have more intensive kin-based institutions, hunter-gatherers emphasize values that focus on independence, achievement, and self-reliance while de-emphasizing obedience, conformity, and deference to authority. (page 224)

This reminded me of comments that Robin Hanson has made about farmers vs. foragers.2 Hanson and Henrich do not necessarily agree completely.

  • [C]ultural evolution has found myriad biological pathways into our brains and behavior… monogamous marriage suppresses men’s competitiveness, risk-taking, and revenge-seeking, while increasing their impersonal trust and self-regulation. (page 273)

This struck me because we seem to be seeing an increase in the number of unmarried men, with adverse consequences.

  • As I was wandering from store to store in the tiny town of Chol-Chol, I noticed something odd… I puzzled over how such small stores, which were so close together, could maintain different prices for the same goods…
  • In retrospect, the answer was obvious… While many households were lifelong friends and relatives, other families were considered undesirable, arrogant, or just unfriendly…
  • The density of these interpersonal relationships constrained market competition… The locals’ decisions to purchase… were embedded in bigger and more important enduring relationships. Of course, buying and selling did occur, but this was more interpersonal exchange than impersonal commerce. (page 301)
“As economists, we tend to assume that whenever and wherever trade took place, it was the sort of impersonal commerce that we observe today.”

As economists, we tend to assume that whenever and wherever trade took place, it was the sort of impersonal commerce that we observe today. But perhaps ancient trade in a kin-based society was part of the rituals that served to cement familial relationships. This is a topic that economists should explore more with anthropologists.

As the church dissolved kin-oriented collectivism,

  • … individuals joined guilds, monasteries, confraternities, neighborhood clubs, universities, and other associations. (page 307)

Henrich is suggesting that a phenomenon that struck Tocqueville about 1830s America was present in the late Middle Ages in Europe.

Henrich argues that intergroup competition strengthens organizations and societies.

  • Remember, we need to conceptually separate intergroup competition from within-group competition… intergroup competition favors beliefs, practices, customs, motivations, and policies that promote the success of groups in competition with other groups… By contrast, within-group competition is the competition among individuals, or small coalitions, that occurs within firms, organizations, or other groups. This form of competition favors… practices that benefit some employees at the expense of the firm.
  • … This means that modern companies, like ancient societies and chiefly institutions, eventually implode in the absence of intergroup competition. (page 347)
For more on these topics, see “The Social Learning Animal,” by Arnold Kling. Library of Economics and Liberty, June 5, 2017. See also Rent Seeking, by David R. Henderson in the Concise Encyclopedia of Economics and Democracy in America, by Alexis de Tocqueville, available at the Online Library of Liberty.

Economists would term this problem rent-seeking. Henrich is applying Public Choice theory to monopolistic firms.

Henrich argues that cultural evolution is faster and stronger than genetic evolution.

  • More recently, the power of cultural evolution over genetic evolution can be strikingly seen in research on the genetic and cultural contributions to educational attainment during the 20th century… Over the entire 20th century, culture has raised Americans’ educational attainment by 9 to 11 years, while natural selection has lowered it by less than 8 months. (page 482)

I believe he is saying that if one uses a polygenic score for educational attainment, the composition of America’s population changed adversely in the 20th century, but educational attainment nonetheless dramatically increased.

Henrich tries to be careful not to merely tell “just-so” stories to describe cultural differences and cultural evolution. He relies instead on statistical studies that test his hypotheses. But many of these studies are of the type that have suffered from improper causal inference and failure to replicate (even among WEIRD subjects). Those who are inclined to hunt for weaknesses in Henrich’s analysis are bound to find some. But I find his work to be highly credible.


[1] Joseph Henrich, The WEIRDest People in the World: How the West Became Psychologically Peculiar and Particularly Prosperous. Farrar, Straus and Giroux, 2020.

[2] Robin Hanson, “Forager v Farmer, Elaborated.” Overcoming Bias, August 31, 2017.

*Arnold Kling has a Ph.D. in economics from the Massachusetts Institute of Technology. He is the author of several books, including Crisis of Abundance: Rethinking How We Pay for Health Care; Invisible Wealth: The Hidden Story of How Markets Work; Unchecked and Unbalanced: How the Discrepancy Between Knowledge and Power Caused the Financial Crisis and Threatens Democracy; and Specialization and Trade: A Re-introduction to Economics. He contributed to EconLog from January 2003 through August 2012.

Read more of what Arnold Kling’s been reading. For more book reviews and articles by Arnold Kling, see the Archive.

As an Amazon Associate, Econlib earns from qualifying purchases.