Book Summary: The WEIRDest People in the World by Joseph Henrich

My latest summary is for The WEIRDest People in the World: How the West became Psychologically Peculiar and Particularly Prosperous by Joseph Henrich, a fascinating book about culture and psychology, with a dash of history.

In it, Henrich explains how Western educated people are rather, well, ‘WEIRD’ in how they think and form judgements, and this ‘WEIRDness’ is how Western countries became rich. Henrich then suggests this all started when the Catholic Church told people to stop marrying their cousins.

Buy The WEIRDest People in the World at: Amazon (affiliate link)

Key Takeaways from The WEIRDest People in the World

• What is WEIRD?
  • WEIRD is an acronym for: Western, Educated, Industrialised, Rich and Democratic.
  • Psychologically, people from WEIRD societies differ from non-WEIRD people in many ways. Henrich organises these into 3 broad groups:
    • Individualism. WEIRD people focus more on themselves and their personal attributes than on their relationships with others. They are less conformist and value control and choice more than non-WEIRD people.
    • Impersonal prosociality. WEIRD people trust strangers more and tend to prefer impartial, universal rules.
    • Perception and cognition. WEIRD people tend to be analytical and abstract thinkers, whereas non-WEIRD people tend to be more holistic. Non-WEIRD people are more likely to focus on relationships between objects than on the properties of the objects themselves.
  • Most humans are not WEIRD. Throughout history, most people lived in societies with intensive kin-based institutions.
• How did people become WEIRD?
  • In Europe between 400-1200 CE, the Catholic Church promulgated a Marriage and Family Program (MFP).
  • A key element of the MFP was its far-reaching incest taboos, which banned cousin marriages. Other notable elements included monogamy, individual consent to marriage, nuclear families, and notions of individual ownership.
  • The MFP effectively weakened traditional kin-based relationships while increasing individualism and impersonal prosociality.
  • The Protestant Reformation beginning 1517 compounded these psychological and cultural changes — it was both a cause and consequence of Europe’s growing WEIRDness.
• Why are WEIRD countries rich?
  • Henrich argues that WEIRD psychology in Europe predated, and therefore enabled, the Industrial Revolution.
  • Individualism increased mobility, allowing people to choose their own occupations, cities and voluntary associations.
  • WEIRD psychology is also correlate with higher patience and self-control, which likely contributed to economic growth and reduced crime.
  • Impersonal prosociality allowed people to trade across bigger markets and cooperate in large networks, forming a large ‘collective brain’.
  • Competition between cities and voluntary associations allowed the most effective norms and laws to spread widely.
  • Lower fertility rates helped Europe escape the Malthusian trap.

Detailed Summary of The WEIRDest People in the World

What is WEIRD?

Henrich uses the acronym WEIRD (Western, Educated, Industrialised, Rich and Democratic) to describe a certain psychological pattern that is common in certain populations (e.g. US college undergraduates), but rare in the rest of the world.

There are many ways in which people from WEIRD societies differ psychologically from non-WEIRD people. Henrich organises these differences into 3 broad groups: individualism; impersonal prosociality; and perception and cognition. [Such a classification is, itself, pretty WEIRD.]

Though Henrich contrasts WEIRD with non-WEIRD behaviours, he is careful to point out that variation is both continuous (there are different degrees of WEIRDness) and multidimensional (there are multiple aspects to being WEIRD). Moreover, Henrich believes we should celebrate psychological diversity, and the book is not intended to denigrate either WEIRD or non-WEIRD people.

Individualism

WEIRD people see themselves as independent agents. Their identities depend on their personal attributes and accomplishments.

In WEIRD societies, kinship ties are generally weaker. While WEIRD people can have many social ties, the ties tend to be ephemeral ones based on shared interests or values, rather than permanent, inherited ties based on membership in a clan.

WEIRD individualism tends to show up in:

• Self-esteem. WEIRD societies show a positive correlation between self-esteem and happiness. Non-WEIRD societies do not.
• Behavioural consistency. The idea of “being yourself” is a WEIRD one. WEIRD people try to behave consistently across different contexts and relationships. They feel cognitive dissonance when they don’t. They are also more likely to make the fundamental attribution error (chalking up another person’s actions to their character or personality, rather than to the context).
• Guilt (vs shame). WEIRD people feel guilt more than shame. Guilt occurs when we fail to live up to our self-imposed standards — e.g. you might feel guilty for eating too much dessert, even if no one knows. Shame occurs when we fail to live up to community standards.
• Lack of conformity. In Asch conformity experiments, WEIRD people conform less than other populations. Conformity rates have also fallen over time as WEIRD societies have become increasingly individualistic. WEIRD people are also less likely to value tradition or to defer to elders.
• Control and choice. WEIRD people tend to prefer, and work harder on, things they choose themselves.
• Ownership. In WEIRD societies, property is owned individually and bequests are personal decisions. The endowment effect is also stronger in WEIRD populations. In non-WEIRD societies, property tends to be communally owned.
• Patience and self-control. WEIRD countries show greater willingness to resist a reward in order to get a bigger reward. Greater patience is linked to higher savings rates and incomes at both national and regional levels.

Geert Hofstede’s well-known measure of individualism finds that the most individualistic societies are America (91), Australia (90) and Britain (89), followed by many European countries (particularly in the north and west), Canada (80) and New Zealand (79). But there is a lot of variation within countries.

Impersonal prosociality

The best way to understand impersonal prosociality is probably by contrasting it with interpersonal prosociality. Interpersonal prosociality is about being nice to those in your in-group — your kin and your friends. With interpersonal prosociality, your cooperation and generosity is relationship-specific, not universal.

By contrast, impersonal prosociality is about how you deal with strangers or abstract institutions like governments. WEIRD people tend to be high in impersonal prosociality:

• Trust and cooperation with strangers. WEIRD people are more likely to agree that, in general, most people can be trusted. They are also more likely to cooperate or show generosity to strangers in lab experiments.
• Impartial, universal rules. WEIRD people are more likely to follow universal rules, even if it hurts their in-group. They are less likely to say they would lie under oath to help a close friend, or to believe that their friend has any right to expect such help. Nepotism is similarly a WEIRD idea — non-WEIRD people are more likely to see it as ‘family loyalty’.
• Impersonal punishments. Related to the previous point, WEIRD people are more likely to punish those who breach their norms of fairness even if they weren’t personally harmed, but are less likely to seek revenge on those who did harm them. Non-WEIRD people are far more reluctant to intervene if they see one stranger harming another.
• Intention in moral judgments. WEIRD people care a lot about intention in determining whether someone acted immorally and how to punish them. Non-WEIRD people focus more on the consequences of an act. In societies tightly constrained by social norms, an individual’s mental state isn’t as relevant. Group culpability is also common (e.g. a father could be punished for a son’s crime) and can even be shared across generations.

Countries with high levels of impersonal prosociality tend to be richer and more innovative. Their governments are generally more effective and less corrupt, and their markets tend to function better. It makes sense that impersonal prosociality thrives when institutions and markets function well. But this creates a chicken-and-egg problem — how do you get there in the first place?

Perception and cognition

WEIRD people’s brains are physically different, because WEIRD populations are highly literate. When people learned to read, it rewired our brains — we developed a specialised neural circuit (‘the Letterbox’) and our corpus callosa (which connects the left and right hemispheres) grew thicker. As a result, WEIRD people tend to be better at verbal memory while non-WEIRD people tend to be better at facial recognition.

These differences show up in the brains of literate vs illiterate populations even when they are genetically indistinguishable. And as recently as 1900, highly literate populations were uncommon.

Perceptive and cognitive differences show up in:

• Analytical and abstract thinking. WEIRD people make sense of the world by breaking things down into parts or isolated objects. They then assign properties to those objects and look for universal rules or abstract principles that help organise those objects into discrete categories. Holistic thinkers, by contrast focus on the bigger picture and the relationships that explain how all parts fit together. They’re less likely to resort to abstract principles.
• Contradictions. WEIRD people hate contradictions. Much of Western law developed as lawyers found and resolved contradictions that emerged when they sought to apply rules universally.
• Focus on foreground vs background. When looking at a picture, WEIRD people focus more on the central actors or objects in the foreground. Research shows that East Asians, by contrast, spend more time looking at the background and broader context.
• Linear trends. WEIRD people tend to assume things will progress as they did in the past, usually in a linear trend. Non-WEIRD people are more likely to assume non-linear and cyclical trends.
• Time thrift. WEIRD people think of time as a scarce resource, and think in terms of “saving time,” “making time,” or “finding time”. One study found that people in individualistic countries tend to walk faster, even after controlling for differences in city sizes.

Most people are not WEIRD

If you’re reading this, you’re probably somewhat WEIRD. But you are an outlier.

Historically, humans weren’t WEIRD

For almost all of human history, societies were organised around kin-based institutions. Kin altruism, the desire to help our close genetic relatives, arose because helping your genetic relatives makes it more likely your genes will spread. In hunter-gatherer times, all societies were rooted in kin-based, interpersonal institutions.

When agriculture developed, cultural evolution favoured norms that helped people cooperate in larger groups. Large, unified groups could better defend farming territory, so had an edge in intergroup competition.

Over time, chiefdoms emerged and grew into premodern states. But even then, societies were still rooted in intensive kin-based institutions. Most people in a chiefdom could trace through blood and marital ties back to the chief. In premodern states, clans or tribes were left to manage their own internal affairs and states usually only intervened in disputes between clans or tribes.

WEIRD today

While WEIRD psychology is more common today, it is far from universal. Even now, around 1 in 10 marriages worldwide are to cousins or other relatives, but most WEIRD people won’t know a single person who married their cousin.

The vast majority of psychology research has been done on WEIRD populations (college students, especially in the US). But this is not at all representative of how humans think — it only describes a small subset of them.

How did people become WEIRD?

Henrich argues that European societies became WEIRD:

• Between 400 and 1200 CE, the Roman Catholic Church (the Church) rolled out their prescriptive Marriage and Family Program (MFP), which undermined kin-based ties and increased individualism.
• Urbanisation increased to unprecedented levels as people moved to new cities and towns.
• Kin-based networks were replaced by voluntary associations like guilds and universities.
• In 1517, the Protestant Reformation compounded the increasingly WEIRD psychology and culture. It did this in various ways, including promoting literacy.

The Church’s Marriage and Family Program

The MFP was a prescriptive package of marriage and family policies including:

• Far-reaching incest taboos. These taboos forced people to look further afield for spouses.
• Monogamy. Monogamy solves the ‘math problem of polygyny’, reducing the proportion of single males in society.
• Individual consent to marriage. This suppressed arranged marriages and weakened patriarchal power.
• Nuclear families. Newly married couples began to set up independent households.
• Individual ownership (and bequests). This helped the Catholic Church become wealthy.

Although Henrich frequently refers to ‘the MFP’, there wasn’t a single, coherent program. For centuries, the policies were pretty scattershot, and different popes applied different rules. (The Eastern Orthodox Church also implemented a version the MFP, but lighter and later.)

Far-reaching incest taboos

Marriage has been important historically because it established cooperative ties between kin-groups.

Before the MFP, cousin marriage was very common — and it’s still practised in some countries today. Similarly, many cultures throughout history required men and women to marry their sister- or brother-in-law if their spouse died, to preserve the bond between the two groups. Without such marriages, bonds between two kin-groups would break upon death of either spouse.

The MFP imposed far-reaching incest taboos that applied to blood relatives and in-laws. Violations came with heavy penalties, including excommunication.

The taboos against cousin marriage extended even up to sixth cousins. Someone looking for a spouse in the 11th century would have had to exclude on average 2,730 cousins as candidates. Such far-reaching incest taboos would have forced people to leave their small towns and villages to find a spouse, increasing urbanisation (see below).

Monogamy

Polygyny is a form of polygamy, in which one man can take more than one wife. Estimates suggest that around 90% of hunter-gatherer societies and 85% of agricultural societies allowed polygyny. It is still legal in much of Africa, Central Asia, and the Middle East.

Polygyny comes with a ‘math problem’ — when elite men can take multiple wives, it can create large pools of low-status, unmarried men. Henrich argues that monogamous norms make groups more cooperative. There is strong evidence to show that when men in monogamous societies get married and have children, their testosterone levels fall. They are then less likely to take risks or engage in antisocial behaviours like crime, violence or drugs. But this effect is muted in polygynous societies where men keep competing for mates even after they’ve had children.

Individual consent to marriage

The individual consent requirement suppressed arranged marriages and began to tie marriages to romantic love. In doing so, the MFP weakened patriarchal power as arranged marriages had been a key source of power for patriarchs.

Consensual marriage also contributed to lower fertility rates because it increased the average age of marriage (shrinking the window for pregnancies) as well as women’s power within their marriages.

Nuclear families

The MFP encouraged newly married couples to set up independent households. The technical term for this is neolocal residence (in contrast to patrilocal residence, where couples live at or near the groom’s father’s house).

Neolocal residence was encouraged through a system of manorialism, where young, often unmarried, people earned money by working in unrelated households. Through manorialism, young people acquired housekeeping skills for setting up their own households. Together with monogamy, neolocal residence facilitated the modern nuclear family.

Individual ownership and bequests

Previously, property was owned communally and would automatically pass to remaining family members on a person’s death. The Church promoted individual ownership, allowing people to bequeath their property to the Church.
MFP norms made such bequests more likely by increasing the chances of clans dying out without inheritors. Mathematically, small clans would die out whenever they failed to produce an adult of the ‘right’ sex. To get around this, clans had used adoption, polygamy, and remarriage to increase the chance of producing a suitable heir. But the Church blocked these strategies by banning divorce and remarriage, and introducing the idea of ‘illegitimate’ children (those born outside a Christian marriage) who had no inheritance rights.

Another reason why bequests to the Church increased was because it promoted the idea that wealthy people could get into heaven by giving away their wealth. Large bequests became so popular that several secular rulers passed laws to stop people from giving away too much, and required them to leave some money for their kin.

The Church also made money by selling exceptions to the MFP policies. In some cases, they agreed to annul a marriage or allow a cousin marriage.

Collectively, these policies made the Church the largest landowner in Europe. By the Protestant Reformation in the 16th century, the Church owned half of Germany and between 25% to 33% of England.

Urbanisation

As medieval Europeans moved to newly forming towns and cities, urbanisation reached unprecedented levels. Since people came from many different places with different customs, cities had to work out new laws and policies to settle disputes. The laws and norms that emerged were rather WEIRD.

Scholars developed impersonal and universal laws by looking for the abstract principles behind the mishmash of existing customs. Lex mercatoria (Merchant Law) expected individuals to be honest and cooperative with strangers. Magdeburg similarly had legislation saying that fathers would not be held liable for murders or assaults committed by their sons, overriding traditions of collective liability.

By contrast, in other complex societies like China, commercial and contract law didn’t substantially develop until the 19th century. While they had contracts and ‘laws’, they weren’t impersonal and codified rules. Instead, the Chinese applied a holistic approach that took into account local customs and interpersonal relationships involve in each particular case.

Voluntary associations

In addition to choosing where they lived, people began to choose their own associates and join voluntary associations like guilds, monasteries, universities and neighbourhood clubs.

Voluntary associations regulated behaviour and helped impersonal trust grow. If an individual exploited a stranger’s impersonal trust, it would damage the reputation of that individual’s association, so voluntary associations made sure to enforce rules and punish violators. In some places, every adult in a town or city was a member of some guild.

Guilds were self-governing associations with their own methods of sharing risks, settling disputes and disciplining members. Over time, guilds gave way to partnerships and joint stock companies. Most of the time, entrepreneurs figured out new ways to share risk and limit liability before lawmakers did.

The Protestant Reformation

Protestantism was both a response to, and cause of, Europe’s growing WEIRDness. It fit better with the growing WEIRD psychology, which is part of why it spread so quickly from 1517. Henrich describes Protestantism as a ‘booster shot’ for WEIRD psychology, which prepared people to participate in the coming Industrial Revolution.

A core idea in Protestantism is that individuals should have a personal relationship with God and Jesus. Salvation depends on one’s personal intentions and beliefs, rather than on rituals or good deeds. Leading Protestant denominations also believe that everyone has a “calling” that uniquely fits their special attributes.

Unlike the Catholic Church’s patriarchal family model where popes had special access to God, the Protestant principle of sola scriptura required people to read and interpret the Bible for themselves. This triggered rapid growth in literacy rates in both men and women (as sola scriptura applied to everyone).

Across western Europe, literacy grew the fastest in heavily Protestant areas. Estimates suggest around 1% of the German-speaking population was literate when Martin Luther began promoting literacy in Saxony. By 1750, at least half of Germany could read. By 1900, adult literacy in Germany was almost 100%. Whereas Catholic countries like Spain and Italy only had literacy rates around 50% at the same time.

Why are WEIRD countries prosperous?

Many people assume people became WEIRD because of economic prosperity and urbanisation. Henrich thinks that is true for most societies we see today — as people grow richer, more educated, and urbanised, they become WEIRDer. However, in Europe, timing suggests that causality seems to go the other way.

Henrich points to many possible factors that seemed to help Europe become prosperous. The main ones seem to be:

• Increased mobility;
• Increased incentives to innovate;
• Patience and self-control;
• Impersonal trust allowing trade and cooperation across big markets;
• Competition favouring effective norms and laws; and
• Reduced crime.

Increased mobility

In intensive kin-based societies, people largely inherited their occupations. But during the European Middle Ages, individuals began to choose their own occupations and could pick ones that suited their particular preferences or strengths.

Increased mobility allowed skilled artisans and craftsmen to move around different towns or cities. They tended to cluster in places, which would have increased competition as well as opportunities to learn from each other. Masters spread their knowledge broadly, forming a large ‘collective brain’. By contrast, artisans in China tended to stay in their rural homelands, away from other artisans.

Increased incentives to innovate

As individualism increased, people began to credit new ideas and insights to those who first came up with them. The notion that a song or idea could be ‘owned’ by an individual would be strange to many customary traditions. But the word ‘plagiarism’ began to spread in Europe during the 16th century as people started to frown on copying others’ work without credit.

People also had greater incentives to innovate and break with tradition thanks to their increased mobility. Throughout history, rulers have frequently cracked down on those with disruptive new ideas. But Europe’s political disunity (many competing states) combined with relative cultural unity (voluntary associations sharing knowledge) meant people could move elsewhere if rulers tried to suppress innovation.

What caused the Industrial Revolution?

Many explanations for the Industrial Revolution suggest causes like representative governments, rise of impersonal commerce, the Enlightenment thinkers, or the development of science.

But these explanations cannot account for the major psychological and modest economic changes that occurred before then. Urbanisation, for example, had been rising in western Europe since 900 CE, and both Holland and England experienced long-term rises in income since the 13th and 16th centuries (respectively). There were also various technological innovations (e.g. the water mill, crop rotation, beer, paper and steel) made between the 6th and 14th centuries.

Henrich’s account explains why Europeans became increasingly open to new ideas and technologies (including those from outside Europe) and began learning from non-kin before the Industrial Revolution itself. So even though the traditional explanations may be partially right, they overlook a key element.

Patience and self-control

‘Patience’ is about how much you discount the future. People who are more patient are willing to wait longer to receive larger payoffs. Patience is positively correlated with many good outcomes. Countries where people show higher levels of patience tend to have higher GDP per capita, more innovation, better educational performance, more effective governments and less crime. The same positive relationship is seen when comparing regions within countries or individuals within regions (even controlling for IQ and family socioeconomic status).

The increase in self-control can also be seen in the sharply falling murder rates in Europe from around 1300 CE. In particular, the murders that fell the most were the spontaneous, barroom brawl-type. Interestingly, the increase in self-control and patience seemed to start in the urban middle class (e.g. merchants, artisans and officials) and spread from there to labourers and elites.

Henrich suggests patience and self-control increased because individualism and impersonal markets may favour such traits. Impersonal markets involve delayed gratification because you have to work now to get paid later, while individualism favours delayed gratification because you get to keep all the rewards from exercising patience. By contrast, societies with strong sharing norms may reduce incentives for patience and self-control — e.g. you save some money, but then some distant cousin needs money and social norms require that you help him out.

[Sharing norms may disincentivise saving at an individual level, but what about at the group level? Henrich points to marshmallow-type experiments like this one to show that people living closer to market towns were more willing to wait for a bigger reward (54%) compared to those in traditional, nomadic camps (18%). However, these experiments have an in-built WEIRD bias in that the greater rewards are offered to individuals, not groups. Maybe we’d see greater patience in non-WEIRD groups if the offers were made to entire groups, because their social norms may then kick in and encourage individuals to be patient for the good of the group.]

Impersonal trust allowing cooperation and trade across big markets

In non-WEIRD societies, markets and trade are generally built on interpersonal relationships and kin-based institutions. One problem with this is that it can strangle market competition. If social norms force you to hire a family member, you won’t be hiring the best person for the job.

Moreover, interpersonal relationships only facilitate cooperation when there is some existing connection. Impersonal prosociality, by contrast, enables cooperation between complete strangers. Europe’s ‘collective brain’
grew during this time as institutions like universities or the Republic of Letters helped knowledge spread across Europe and allowed intellectuals to learn from each other.

Competition favouring effective norms and laws

Some believe that Western law, science and democracy were the products of reason and rationality. Henrich disagrees. It was more a “grinding process of myopic groping” due to intergroup competition than an “intellectual epiphany rooted in some abstract rationality”.

As urbanisation increased, cities and other voluntary associations competed with each other. Those with the most appealing laws, policies and taxes attracted more migrants. For example, over 80 cities explicitly copied Magdeburg’s laws and institutions. Through such competition between cities and voluntary associations, effective norms and best practices spread.

Many of the newly forming cities and towns had elections or some degree of self-governance. This was unusual — no city in China or the Islamic world had this at this time. Democratic practices like voting or consensus building simply don’t work that well in intensive kin-based societies. When group loyalty norms are very strong, elections are won by the biggest clans or ethnic groups rather than the most effective ones because members can’t ‘switch teams’ easily.

Lower fertility rates to escape the Malthusian trap

In the past, rising prosperity came with increased population growth. This created a Malthusian trap: when human populations grow at exponential rates, economic growth can’t keep up. So even when some societies saw a burst of economic growth, they couldn’t sustain it.

The growth prompted by the MFP in Europe was different because the MFP also created norms that constrained population growth. As noted above, individual consent to marriage lowered fertility (by increasing the average age of marriage and women’s power within their marriages). Increased mobility and weakened kin-based institutions were also factors, because women experienced less pressure from relatives to get pregnant and got less childcare support if they did.

Evidence

Henrich points to a ton of evidence to support his claims. There’s far too much to cover in this summary, but here is a brief summary of what he covers:

• Link between duration of MFP exposure and:
  • Strength of kin-based institutions today; and
  • Various measures of WEIRD psychology.
• Link between (historical) kinship intensity in an area and how WEIRD the people in or from that area are today:
  • Kinship intensity is measured using both an index of traditional kin-based norms and actual rates of cousin marriage.
  • WEIRD psychology is measured using a very wide range of measures — there’s the obvious survey responses and lab experiments, but also real-world data on things like voter turnout, political involvement, blood donations, corruption and mafia activity.
  • Henrich also uses data with second-generation immigrants — i.e. even for individuals living in the same country, those whose parents came from countries with greater kinship intensity were less WEIRD.
• Link between Protestantism and many traits (some of these showed effects over and above the impact of kinship intensity or MFP dosage, so it seems to be Protestantism in particular):
  • WEIRD psychology such as individualism and impersonal prosociality;
  • literacy;
  • patience, self-control, work ethic, economic growth; and
  • suicide rates.
• Link between WEIRD psychology and various measures of innovation.

Of course, the evidence will never be perfect because causation is really hard and can depend on how multiple factors interact with each other.

For example, with the Industrial Revolution, Henrich makes the pretty plausible claim that the emerging apprenticeship system spurred innovation. But it’s too simplistic to say that “apprenticeships” were the cause — after all, China had a similar apprenticeship system, too — it’s apprenticeships combined with:

• increased mobility, which meant masters and journeymen moved between towns and cities;
• intergroup competition, which meant that cities and guilds had incentives to attract the best people; and
• social norms that incentivised people to share new insights and ideas and disincentivised stealing from others.

Since Henrich’s explanation depends on multiple elements, one could easily accuse it of being a “just so” story. But I think that’s unavoidable given the nature of the questions Henrich asks. Occasionally Henrich does put out some minor theories without a ton of evidence (e.g. the link between interest rates and patience), but he does so without zeal.

To his credit, he repeatedly warns against inferring causation from simple causation, and seems to make reasonable attempts to control for potential confounders where data permits. He also caveats his claims appropriately. For example, when referring to priming experiments, he notes how “notoriously delicate” they are. When talking about experiments that show intergroup competition increasing cooperation and impersonal trust, he warns against generalising to societies currently based on interpersonal trust.

Henrich also provides excellent footnotes so you can follow up if you want. I looked up the abstracts for a fair few studies and didn’t find any cases where he misrepresented research findings. (But I am by no means an expert in this space.)

Overall, I found Henrich a careful, credible writer. I’m not fully convinced of all of Henrich’s theories — the evidence is, after all, limited and can be interpreted in different ways — but I didn’t find any obvious reasoning errors.

Other Interesting Points

• Individualism and impersonal prosociality don’t always go together. The Matsigenka people in the Amazon are even more individualistic than WEIRD people, but are very low on impersonal trust.
• People who geographically moved as a child make less of a distinction between friends and strangers. They also tend to have larger social networks, stronger preference for novelty, and perhaps even more creative thinking.
• Nearly half of all US adults believe in ghosts (source). A similar proportion of Icelanders believe in elves (source).
• People with better mentalising abilities and greater empathy are more likely to believe in supernatural agents, probably because they can conjure up a richer mental image. This may partly explain why global surveys show women (who tend to be better at mentalising and empathy) are more likely to believe in God. Once corrected for these abilities, women and men believe in God and supernatural agents at the same rate.
• Even kings and elites have been subject to the whims of the ‘gods’. For at least two centuries, Mayan rulers had to pierce their penises with stingray spines and then draw bark strands through the hole.
• Brothels were legal and common in the Roman Empire. This may explain why Latin has 25 words for ‘prostitute’.
• Proximity to ports and rivers is generally correlated with greater impersonal prosociality, likely due to the increased trading opportunities. But one exception to this is Africa, possibly because of the slave trade — between 1500 and roughly 1800, proximity to the ocean in Africa meant a greater threat of enslavement.
• One ingenious data source for studying how people used to spend their time is to look at court records where witnesses reported what they were doing at the time of a crime.

My Review of The WEIRDest People in the World

I found The WEIRDest People in the World fascinating. As noted above, I’m not sure I fully buy all of Henrich’s claims, but I still loved reading Henrich’s explanation. I particularly enjoyed learning about impersonal prosociality. It seems so important to understanding differences between people, yet it’s surprisingly rarely discussed.

My family migrated from a non-WEIRD to a WEIRD country when I was very young, which is probably (partly) why I’ve always been higher in impersonal prosociality than my family members. This caused some conflict growing up. My mother expected me to automatically take her side in any argument with people outside our core family. Instead, I’d try to maintain an ‘objective’ stance and understand both sides’ perspective before offering up my view. My approach always infuriated my mother, and I always thought her expectation was completely unreasonable. Looking back, these conflicts came down to fundamental differences on impersonal vs interpersonal prosociality.

That said, the book was quite a hard read (and even harder to summarise!). Henrich is a professor of evolutionary biology at Harvard and he definitely seems to know his stuff, but the level of detail he goes into is overwhelming. Henrich also favours long, compound, sentences that take some effort to parse — for example:

That’s 52 words in a single sentence!!

The structure of the book also jumps around a lot and there’s plenty of repetition. Yet there were also tons of interesting titbits and ideas that I’ve had to leave out in my summary. So I don’t want to give the impression that it could’ve just as easily been a 400-page book — but, at 704 pages, it certainly could have been streamlined.

Despite my minor gripes about readability, overall I thought the book was well worth reading. It’s kind of incredible that you can get the benefit of so much of Henrich’s decades of study and research for the same price as your average self-help book.

Let me know what you think of my summary of The WEIRDest People in the World in the comments below!

Buy The WEIRDest People in the World at: Amazon <– This is an affiliate link, which means I may earn a small commission if you make a purchase through it. Thanks for supporting the site! 🙂

If you enjoyed this summary of The WEIRDest People in the World, you will probably like:

• Book Summary: The Righteous Mind by Jonathan Haidt — Haidt was Henrich’s colleague at NYU Stern Business School. His book focuses on how morality differs across cultures and in politics.
• Book Summary: Sapiens by Yuval Noah Harari — Harari’s book is a sweeping account of our species’ history, from the Cognitive Revolution 70,000 years ago to its publication in 2011.
• Book Summary: Guns, Germs and Steel by Jared Diamond — Diamond’s Pulitzer-winning book explores why societies grew and acquired certain technologies much earlier than others. It popularised the field of ‘big history’.