Review: The WEIRDest People in the World

Review: The WEIRDest People in the World by Joseph Heinrich

This is a huge book, both in ambition and scope. It took me a months to read and and digest as it presents a number of far-reaching concepts such as cross-cultural psychological variation, cultural evolution and a history of European psychology and social institutions. Each of these could encompass a life's work much less a few chapters, and yet we have another topic and another. A veritable banquet.

Heinrich's main thesis is that a number of Catholic church policies enacted from 500 to 1000 AD related to marriage and family changed European psychology and institutions in ways that eventually culminated in the Industrial Revolution and the rise of the West. 

Rather than simply walk us through his thesis, Heinrich first explains what legs and feet are and then painstakingly explains the mechanisms of biomechanics so we might put the pieces together and walk through ourselves.

Part 1 explains to us first that cross-cultural psychological diversity exists and that people from backgrounds roughly corresponding to 'the West' are particularly different from many other cultures around the world. 

These people are WEIRD:

    Western, Educated, Industrialized, Rich, Democratic

As befits the acronym, WEIRD people exhibit a package of psychological characteristics that are either unusual or inhabit the extreme ends of a spectrum. These characteristics include: individualism, analytic thought, non-conformity, control-orientated (vs external locus), universal & categorical thinking vs. contextual and situational thought, guilt (vs. shame), and self-identification through personal attributes rather than social relationships. Are you WEIRD? If so you are less likely to think nepotism is morally acceptable and more likely to feel cognitive dissonance (i.e. experiencing discomfort at holding two conflicting beliefs).

Studies are presented that show people from WEIRD backgrounds measurably differ from most others in these psychological attributes. After a brief lament for the replication crisis in the field of Psychology and wonder at what kinds of insights might emerge with a more representative sample of global psychological variation, the next question one asks is why?

Not content with a superficial answer, Heinrich takes us all the way back to the intersection of human evolutionary psychology and culture. He argues that humans aren't smart enough individually to learn how to survive and thrive in their environments, but rather they are evolutionarily primed to learn from one another. Within this context culture acts as a means of transmitting knowledge across generations. Cultural learning is accumulated over time and can evolve as successive groups learn, test, adapt and compete with other groups harbouring other bodies of cultural knowledge. This section is an abbreviated introduction to content elaborated in Heinrich's previous book The Secret of Our Success: How Culture is Driving Human Evolution, Domesticating Our Species and Making Us Smarter (spoiler warning).

Cultural evolution explains the 'wisdom of the ancients' effect where humans are able to develop answers to problems they have no technological or theoretical capacity to understand. One example is nixtamalization, a process in which alkaline solutions are added to maize to remove mycotoxins and increase nutritional value. Central Americans a millennia ago didn't understand that boiling corn in limestone rocks made maize more nutritious, but the practice would have helped groups that adopted the practice to outcompete groups that did not. The successful practice would have been adopted by other groups and gradually the process was adapted over centuries to include boiling maize in lime water using more efficient types of pots. Other examples of cumulative cultural evolution include traditional medicines, tool-making, essentially all behaviors too complex to have been invented by a single person. 

Heinrich describes circumstances that lend themselves to cultural evolutionary transfer. Areas that are highly important but difficult or risky to personally experience through repetition. Religious rituals, food norms and social institutions all fit the bill. He also claims that learning by observing others makes the learner more likely to empathize with and share beliefs with the model. The process is enhance through things like mirroring behaviors, communal rituals and music, not coincidentally very common methods of transmitting important cultural knowledge.

This explains why things like apprenticeships were effective educational tools and suggests that perhaps they should be reexamined in modern education. I'm also left wondering whether the overall reduction of mass rituals in our society (religious meetings, dances, community gatherings) haven't damaged social solidarity and contributed to the isolation of modern life. 

The next chapter lays out several forms of social organization and explains how societies scale up in size. Heinrich points out that from the standpoint evolutionary psychology, humans are predisposed to create social institutions based on kin groups, advantaging their own genetic lines. Kin-based institutions based on family ties are the norm for human societies and culture but they are limited because as size increases relational proximity decreases and it becomes too difficult to track the complex web of relationships across generations. Patrilineal clans (grouping along fathers' family lines) and segmentary lineages (branching groups of patrilineal clans) both evolved as kin-based solutions to this problem. 

As these kin-based hierarchies expand and become formalized a two-tiered society of nobles and common people can emerge. As population grows administrative needs increase and ruling classes often create formal bureaucracies, thus birthing early kingdoms. 

Another, non-kin-based institution that can help scaling societies is age set rituals. These are rituals that help mark passage from one stage of life to another, forming bonds of social solidarity amongst individuals. Some examples are marriage ceremonies or coming-of-age rites for young adults. In kin-based societies these rituals may become dominated single clans like other institution, but this isn't necessarily so. For example, among the Ilahita in New Guinea different clans are systematically mixed among different ritual groups to provide a degree of trust among all families rather than clustering around their own individual clans. Aside from age set rituals, military conflict can cause societies to cohere and help with scaling process, but this type of social cohesion frequently falters when conflicts end. Historically, the majority of societies around the world have built on enlarged kin-based institutions. 

The next chapter is about how religion can help extend trust beyond kin. It covers a number of experiments often using subconscious priming to show that religious ideas can cause people to act in altruistic, prosocial ways. These effects are stronger in moralizing religions, that is religions that compel strict moral codes at the risk of divine punishment. Heinrich claims that religions in the past frequently had less moralizing elements and that Gods did not compel individuals to hold a shared set of values. Over time, however, religions that had strong rewards and punishments, moral codes and costly requirements of obedience have tended to win out in intergroup competition. Such religions encourage greater social cohesion and impersonal trust, creating a community of the faithful and increasing the odds of successful intergroup competition. This success increases the chance that new groups will adopt the practices and institutions of their more successful neighbors.

One interesting fact that leapt out was about how some people are particularly good at empathy and mentalizing (i.e. recognizing or imagining the mental states of others) tend to be better able (and more likely) to impart anthropomorphic traits and agency to spirits or inanimate objects. This may explain why women tend to be both more empathetic and more religious than men.

Part 1 is fascinating, particularly the insights about how societies grow and adapt and how different social organizations, institutions and religious forms affect the psychologies of their respective populations (perhaps more in another post). The chapters mainly serve, however as building blocks to Heinrich's argument that explain how things changed once kin-based institutions were ripped apart by the Catholic Church.

How did WEIRD people become WEIRD? 

Part 2 examines a series of religious doctrines instituted by the Catholic church from roughly 500-1000 AD. These including the banning of polygamous marriage, cousin and other familial marriage, the marriage of brothers to their widowed sisters-in-law, arranged marriage (requiring public consent), and prohibited prostitution and discouraged adoption. Newly married couples under the manorial system often moved away from their families to find work (neo-local residence). Other important changes include the introduction of will-based inheritance rather than shared inheritance based on kin, the idea of individual ownership rather than collective ownership by clan.

These changes, collectively referred to by Heinrich as the Marriage and Family Program (MFP), were introduced piecemeal rather than as a single unified program and came into effect gradually at different times in different places. Taken together the MFP had huge effects on social institutions and psychology. By limiting the the acceptable pool of marriage partners, patrilineal clans were starved of male heirs and clan lineages were broken. People had to travel farther to find acceptable partners, further degrading intensive kinship bonds. By introducing the idea of legitimacy, adoption ceased to be an option for extending family lines. Individual property rights attacked the livelihood of kin-based institutions under which families often held land collectively. Individuals were less likely to be subjected to collective responsibility for their families' actions and more likely to be judged based on individual behavior. Introductions of will and testament instead customary inheritance laws disinherited the extended family in favor of preferred children and often donations to the Church. Requiring public consent for marriage and limiting cousin marriages took away political tools patriarchs used for extending clan ties. In sum, these changes slowly eroded the kin-based social structures that had previously dominated society. 

As a result the Church increased in wealth and importance. Social safety nets were more necessary as people were less able to rely on local connections and extended family in times of need. 

The changes wrought by the MFP also affected the psychology of Europeans, causing them to be more individualistic, analytical, to focus more on intentions when judging morality and harbour guilt more than shame. They also made people less impatient, less risk-seeking and less conformist.

Part 3 looks at how new institutions formed and how these reciprocally affected and were molded by WEIRD psychology. It also answers questions about what replaced the kinship-based institutions broken down by the MFP. After the fall of the Carolingian Empire, people increasingly moved into towns for personal protection. Heinrich tracks the rise of urbanization along with increased participation in voluntary organizations such as guilds, monastic orders and universities. Urbanization and population mobility contribute to rapid exchange of ideas fostering cultural evolution. Increases in wage labour caused WEIRD people to increasingly value time and productivity. Moving to the cities further reduced kinship intensity and made people more receptive to new ideas and caused greater economic specialization. Economic specialization, and the need to create new relational networks in cities forced people to 'sell themselves'. This pushed personality differentiation and a tendency for people to identify themselves based on individual ability rather than relational status. 

One fascinating implication is that the widely-studied five-factor model of personality might be culture-specific. In other cultures different personality factors (as opposed to extraversion, openness, agreeableness, neuroticism and conscientiousness) might develop. For example, the farmer-forager Tsimane' people in Bolivia appear to lack the 'Big-5' personality differentiation and instead vary along two other personality axes: industriousness and interpersonal prosociality.

The rise of voluntary associations such as guilds, monastic orders, neighborhood associations and universities marked other changes. Proximity to sites of Cistercian monasteries appears to be correlated with measures of work ethic even today. Markets and competition among market towns helped spread the kinds of impersonal prosocial values necessary to do business with strangers and formal legal packages leading to participatory government like town charters. 

Democracy and participatory government emerged from legal charters governing towns and villages. The concept of natural rights emerged from Catholic canon law. Heinrich contends that institutions like democracy and the concept of universal rights were not inevitable, born of an inherent sense of justice or rationalism, but rather the product of WEIRD personality traits and values, universalizing morality, individualism, impartiality, and more. Essentially WEIRD people were pre-programmed to be compatible with the kinds of institutional packages that emerged. 

Heinrich isn't particularly optimistic about the possibility for globalizing all sorts of institutions that have emerged in WEIRD societies. He suggests that mismatches between cultural psychology and imported institutions are responsible for numerous failures of globalization as non-WEIRD societies try to copy WEIRD government, economic and legal norms. It would be interesting to see what sort of packages of institutions would work well combining kinship-based norms and modern economics. 

One other thought that comes to mind is how WEIRD psychology seems so salient in the Culture Wars. One of the factors that contributed to WEIRD success is impersonal trust and impersonal fairness and pro-sociality. Basically WEIRD people treat strangers relatively well, almost as if they were in-group members and this benefits all of WEIRD society by allowing people to cooperate for the common good. Today, as the West is increasingly polarized these benefits seem to have diminished along with our sense of impersonal trust. I would be interested to see whether data bears out my intuitions here. 

Perhaps the things that are causing tribalism are in fact related to WEIRDness? Non-conformity, individualism, universal morality, third-party norm enforcement, a tendency to attribute choices to individual character attributes rather than situational factors... These could all contribute to creating factions that think they know what is best and won't rest until they win over the other tribe for the better of society. Yikes.

Part 4 explains how all of the combined historical changes to WEIRD culture and psychology combined to drive innovation and economic expansion from the Industrial Revolution to the present day. The most interesting part of this section is the idea that innovation occurs not because of genius inventors nor even education levels or universities or some other manifestation of knowledge. According to Heinrich, the two most important factors governing innovation are having a large group of connected minds and having a great number of connections between people. As this 'collective brain' becomes larger and better connected, innovations result as a ideas are recombined in novel ways, a kind of intellectual network effect.

In case you thought I'd exhausted the contents of this book, there's much more! Monogamy makes sperm counts go down! Kinship intensity may be a result of communal irrigation projects! The Fundamental Attribution Error in psychology isn't fundamental but actually rather WEIRD! It goes on and on. 

Throughout the book, Heinrich uses a huge variety of methods to provide evidence for his findings. Historical statistics are frequently used measure the effects of the Church's marriage and family policies. Heinrich records how early and for how long different areas were exposed to the MFP, giving them an 'MFP score'. He then compares this MFP score with with more modern measures showing a  correlation between duration of church exposure and higher individualism and impersonal trust, and a negative correlation with kinship intensity and conformity. Heinrich also looks at the duration of a given population's exposure to bishoprics and finds the same correlations even when controlling for religion. Other factors he tracks are marital records and Church legislation and correspondence.

Heinrich uses the Kinship-Intensity Index (KII) and societal rates of cousin marriage to quantify the concept of kinship intensity. The KII combines measures of cousin marriage rates,  polygyny (multiple wives), inheritance norms, social customs and in-group marriage. Heinrich provides evidence that the MFP broke down kinship ties by showing that areas with high MFP scores have lower modern rates of kinship intensity. In other studies, areas with high kinship intensity show higher rates of conformity and lower impersonal trust, individualism, and less weight given to intentions when judging morality (judge similar crimes equally without regard to motivation). I'm condensing many studies into one statement here, but these WEIRD and non-WEIRD differences seem to hold even when controlling for a number of variables including education, income, ethnicity, etc. They also hold when comparing people within the same country who have moved from areas with differing levels of kinship intensity and cousin marriage.

Some of the data used is quite unique, like rates of public blood donation, relative numbers of diplomatic parking tickets and experimental evidence show how WEIRD people are more likely to punish the ungenerous in an experimental giving game (norm-enforcement). 

One study looked at different communities in Switzerland, measuring how long they had been democratic and how this might affect their conditional cooperation (how much they would reward someone who cooperated with them in an economic experiment). Historical events such as Napoleon's conquest in 1803 (instituting democracy) and the death of Duke Zahringen in 1218 (allowing self-determination) provide quasi-random inflection points to help rule out other confounders. The findings showed that people in communities with longer democratic traditions were more likely to show conditional cooperation. I love the creativity of pulling experiments out history. 

There are potential problems with this kind of experimentation. History generates a near infinite amount of data that can be selectively collected and recombined to confirm almost any hypothesis. Single measures for many of the abstract concepts presented do not exist, and even if we had simple, observable tests, how could we retroactively experiment on people long dead? In addition, most of the research presented in the book was done by other scholars, and there is always a chance a good a faith citation may be based on faulty experimental design.

Despite these risks, I think Heinrich has made strenuous attempts to avoid some of the more common pitfalls. Potential confounding variables are examined with almost every finding and he often employs several methods of measuring the most important conclusions. With a book of this breadth there are bound to be mistakes and biases. Every historical event has more causes than can be explained with any single thesis. Still, I suspect many of the effects outlined in this book are real, and even if it turns out that I'm wrong, the ideas are fascinating enough to be worth consideration.

It is difficult to write a positive book review. You could simply rattle off praise, but to explain why it is good and to grapple with the content is hard. One of the main reasons I wanted to write this review was to grapple with the text and prevent the bulk of it from slipping out of memory. I know I can't hold it in my mind indefinitely, but perhaps this review will convince others to read and remark on the book. What conversations there are to be had!

Edit:

I have recently run across some strong criticisms of the book written by a Charles Freeman, a medieval historian. To summarize, he thinks Heinrich overgeneralizes a lot of the variation in European people and that he ignores the historical state of Europe before the fall of Rome (and how some WEIRD features were present in Rome). Freeman claims that the Church didn't have enough power to enforce the MFP and that most people continued to marry and procreate according to local custom, invalidating Heinrich's thesis.

The most damning thing in Freeman's critique was always how Heinrich's theories were going to fail: History is almost never mono-causal. It's difficult to sell a book entitled The WEIRDest People in the World: One of several causes that may have contributed to Western prosperity, though that title would probably be more accurate. That said, even if the Church was generally ineffective at imposing the MFP, present-day data on kinship intensity and cousin marriage seems to imply there's some kind of effect on psychology.

Another issue relates to the replicability of priming studies. Much of Heinrich's evidence for the power of religion to affect people's behavior is based on priming effects. I don't know how replicable these specific studies are, but given that much of the field is in jeopardy for using poor statistical methods, it is worth approaching these sections with skepticism.

Personally, I've updated to hold Heinrich's specific theory as to the MFP as possible but unproven. I still find the ideas discussed in the book absolutely worth the read.