RELEVANCE
A lot of things we take for granted are rooted in our cultural and cultural psychology. Jon Henrich’s work lays out his hypothesis for where the unusual traits of Western societies may have come from and in the process offers a framework for thinking about cultures, psychology, group competition and cultural evolution.
Like Kauffman — Henrich’s analysis is dense and nuanced. If you are new to this material, it probably won’t make a lot of sense the first time you read it, and his ideas will just seem weird. But it’s all very thoroughly researched and he does a very thorough job of connecting all the pieces. So it’s weird, but true?
Ideas like the fact that private property was created by the church so it could be given to them to save souls and increase their wealth (a preadaptation) and then went on to play other roles like creating incentives for individuals to create wealth which didn’t exist when property was owned by families or clans… well those are useful, and a reminder that a lot of economics may have mathematical rigor, but it’s depth often fails to exceed that of a puddle.
Henrich is useful to us for four reasons:
His framework and findings are complexity applied to cultural evolution and consonant with Kauffman’s frameworks.
He emphatically reminds us that what makes sense to us as WEIRD people will seem weird to most people.
The logic itself is strange and unexpected — but all fits, reminding us that solutions to real problems violate our preconceptions (if our preconceptions about something were right then we wouldn’t have a problem understanding it?).
He shows us once again that thinking in terms of processes or systems yields insights.
THE WEIRDEST PEOPLE IN THE WORLD
by Joseph Henrich
[Emphasis in the passage below is ours.]
WEIRD Families
The families found in WEIRD societies are peculiar, even exotic, from a global and historical perspective. We don’t have lineages or large kindreds that stretch out in all directions, entangling us in a web of familial responsibilities. Our identity, sense of self, legal existence, and personal security are not tied to membership in a house or clan, or to our position in a relational network. We limit ourselves to one spouse (at a time), and social norms usually exclude us from marrying relatives, including our cousins, nieces, stepchildren, and in-laws. Instead of arranged marriages, our “love marriages” are usually motivated by mutual affection and compatibility. Ideally, newly married couples set up residence independent of their parents, establishing what anthropologists call neolocal residence. Unlike patrilineal clans or segmentary lineages, relatedness among WEIRD people is reckoned bilaterally, by tracking descent equally through both fathers and mothers. Property is individually owned, and bequests are personal decisions. We don’t, for example, have claims on the land owned by our brother, and we have no veto on his decision to sell it. Nuclear families form a distinct core in our societies but reside together only until the children marry to form new households. Beyond these small families, our kinship ties are fewer and weaker than those of most other societies. Though kinship does assert itself from time to time, such as when U.S. presidents appoint their children or in-laws to key White House posts, it usually remains subordinate to higher-level political, social, and economic institutions.
Let’s begin by putting some numbers on the kinship patterns described above using the Ethnographic Atlas, an anthropological database of over 1,200 societies (ethnolinguistic groups) that captures life prior to industrialization. Table 5.1 shows five of the kinship traits that characterize WEIRD societies: (1) bilateral descent, (2) little or no cousin marriage, (3) monogamous marriage only, (4) nuclear family households, and (5) neolocal residence. The frequencies of these WEIRD kinship traits vary from a high of 28 percent, for bilateral descent, to a low of 5 percent, for neolocal residence. This suggests that most societies have long lived in extended family households, permitted polygamous marriage, encouraged cousin marriage, and tracked descent primarily through one parent. Taken separately, each trait is uncommon, but in combination, this package is extremely rare—WEIRD.
To see just how rare these patterns are, we can count how many of these kinship traits are possessed by each society in the Atlas. This gives us a score from zero to five that tells us how WEIRD a society is in terms of kinship. Figure 5.1 shows the results: over half of the societies in the Atlas (50.2 percent) possess zero of these WEIRD kinship traits, and 77 percent possess either zero or only one of these traits. At the other end, fewer than 3 percent of societies possess at least four of them, and only 0.7 percent possess all five traits. Notably, these tiny percentages include a small sampling of European societies, like the Irish and French Canadians of 1930. So, 99.3 percent of societies in this global anthropological database deviate from the WEIRD pattern.
The aspects of traditional kinship found in the Atlas open a window not only on the world prior to industrialization but also on the social norms that remain important even today. Consider this question: How many people do you personally know who married their cousins?
If you know none, that’s WEIRD, since 1 in 10 marriages around the world today is to a cousin or other relative. Based on data from the latter half of the 20th century, Figure 5.2 maps the frequency with which people marry their first or second cousins or other close relatives (uncles, nieces). Remember that second cousins share a pair of great-grandparents. For the sake of simplicity, and because most marriages to relatives involve cousins, I’ll refer to this as cousin marriage. At one end of the spectrum, we see that people in the Middle East and Africa marry relatives at least a quarter of the time, though in some places these numbers reach up above 50 percent—so over half of marriages are among relatives. In the middle, countries like India and China have moderate rates of cousin marriage, though it’s worth knowing that in China, when the government began promoting “modern” (Western) marriage in the 1950s, it outlawed uncle-niece marriage and, later, first cousin marriage. By contrast, really WEIRD countries like the United States, Britain, and the Netherlands have rates of about 0.2 percent, or one-fifth of 1 percent.
So, how did WEIRD kinship become so unusual?
Many assume that the peculiar nature of WEIRD families is a product of the Industrial Revolution, economic prosperity, urbanization, and modern state-level institutions. This is sensible, and certainly appears to be what’s happening in much of the world today, through globalization. As non-WEIRD societies have entered the global economy, urbanized, and adopted the formal secular institutions of WEIRD societies (e.g., Western civil codes, constitutions, etc.), their intensive kin-based institutions have often begun to slowly deteriorate, resulting in the spread of WEIRD kinship practices, particularly among educated urbanites. Nevertheless, against this onslaught of global economic and political forces, intensive kin-based institutions have proven themselves to be remarkably resilient.
In Europe, however, the historical order was reversed. First, between 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—hereinafter the Western Church or just the Church. Then, from the ruins of their traditional social structures, people began to form new voluntary associations based on shared interests or beliefs rather than on kinship or tribal affiliations. In these European regions, societal evolution was blocked from the usual avenues—intensifying kinship—and then shunted down an unlikely side road.
The key point for now is that the dissolution of intensive kin-based institutions and the gradual creation of independent monogamous nuclear families represents the proverbial pebble that started the avalanche to the modern world in Europe. Now let’s look at how this pebble was first inadvertently kicked by the Church.
Dissolving the Traditional Family
The roots of WEIRD families can be found in the slowly expanding package of doctrines, prohibitions, and prescriptions that the Church gradually adopted and energetically promoted, starting before the end of the Western Roman Empire. For centuries, during Late Antiquity and well into the Middle Ages, the Church’s marriage and family policies were part of a larger cultural evolutionary process in which its beliefs and practices were competing with many other gods, spirits, rituals, and institutional forms for the hearts, minds, and souls of Europeans. The Church vied against ancestor gods, traditional tribal deities such as Thor and Odin, the old Roman state religion (Jupiter, Mercury, etc.), and various Mediterranean salvation cults (Isis and Mithras, among others), as well as diverse variants of Christianity. These other Christian sects were serious competition and included the Nestorian, Coptic, Syrian, Arian, and Armenian Churches. The Goths, for example, who played a role in the fall of the Western Roman Empire, were not pagans but Arian Christians. Arians, major heretics in the Western Church, held the astonishing view that God the Son (Jesus) was created by God the Father at a particular point in time, making the Son subordinate to the Father.
Today, it’s clear that the Western Church won this religious competition hands down. Christianity is the world’s largest religion, having captured over 30 percent of the global population. However, 85–90 percent of modern Christians trace their cultural descent through the Roman Catholic Church, back to the Western Church in Rome, and not through the many other branches of Christianity such as the Orthodox or Oriental Churches. This outcome was far from clear when the Western half of the Roman Empire broke up. The Eastern Orthodox Church, as the state religion of the Byzantine Empire, was backed by powerful Roman state institutions and military might. The Nestorian Church, based in cosmopolitan Persia, had established missions in India by 300 CE and in China by 635, many centuries before the Roman Catholic Church would arrive in these places.
Why did the Western Church so dominate in the long run, not only exterminating or commandeering all of Europe’s traditional gods and rituals but also outpacing other versions of Christianity?
There are many important elements to this story. For example, Rome’s geographic location far from the main political action in Europe may have provided the pope—the bishop of Rome—with some freedom to maneuver. In contrast, other leading bishops, such as those in Constantinople, were under the thumb of the emperors of the Eastern Roman Empire. Similarly, much of northern Europe was relatively technologically backward and illiterate at this point, so the pope’s missionaries might have had an easier job of making converts there, for the same reasons that North American missionaries were so successful at making converts in Amazonia during the 20th century. The locals were just more inclined to believe new religious teachings when missionaries showed up with fancy technologies and seemingly miraculous skills, like reading.
Complexities aside, the most important factor in explaining the Church’s immense success lies in its extreme package of prohibitions, prescriptions, and preferences surrounding marriage and the family. Despite possessing only tenuous (at best) roots in Christianity’s sacred writings, these policies were gradually wrapped in rituals and disseminated wherever possible through a combination of persuasion, ostracism, supernatural threats, and secular punishments. As these practices were slowly internalized by Christians and transmitted to later generations as commonsense social norms, people’s lives and psychology were altered in crucial ways. These policies slowly transformed the experience of ordinary individuals by forcing them to adapt to, and reorganize their social habits around, a world without intensive kin-based institutions.
Throughout this process, the Church was competing not only with other religious complexes, but also with intensive kin-based institutions and tribal loyalties. By undermining intensive kinship, the Church’s marriage and family policies gradually released individuals from the responsibilities, obligations, and benefits of their clans and houses, creating both more opportunities and greater incentives for people to devote themselves to the Church and, later, to other voluntary organizations. The accidental genius of Western Christianity was in “figuring out” how to dismantle kin-based institutions while at the same time catalyzing its own spread.
UP TO THE STARTING LINE
What did kinship look like among the tribes of Europe before the Church went to work? Unfortunately, we don’t have the kind of detailed studies of kinship and marriage that anthropologists have provided for traditional societies in the 20th century. Instead, researchers have cobbled together insights from diverse sources, including (1) early law codes; (2) Church documents, including the many letters exchanged by popes, bishops, and kings; (3) travelers’ reports; (4) saints’ biographies; (5) Nordic and German sagas; (6) ancient DNA analysis (applied to burials); and (7) kinship terminologies preserved in ancient writings. Broadly speaking, these sources make it clear that prior to the Church’s efforts to transform marriage and the family, European tribes had a range of intensive kin-based institutions that looked a lot like what we see elsewhere in the world.
Here are some broad patterns in the tribal populations of pre-Christian Europe:
1. People lived enmeshed in kin-based organizations within tribal groups or networks. Extended family households were part of larger kin-groups (clans, houses, lineages, etc.), some of which were called sippen (Germanic) or septs (Celtic).
2. Inheritance and post marital residence had patrilineal biases; people often lived in extended patrilineal households, and wives moved to live with their husbands’ kinfolk.
3. Many kinship units collectively owned or controlled territory. Even where individual ownership existed, kinfolk often retained inheritance rights such that lands couldn’t be sold or otherwise transferred without the consent of relatives.
4. Larger kin-based organizations provided individuals with both their legal and their social identities. Disputes within kin-groups were adjudicated internally, according to custom. Corporate responsibility meant that intentionality sometimes played little role in assigning punishments or levying fines for disputes between kin-groups.
5. Kin-based organizations provided members with protection, insurance, and security. These organizations cared for sick, injured, and poor members, as well as the elderly.
6. Arranged marriages with relatives were customary, as were marriage payments like dowry or bride price (where the groom or his family pays for the bride).
7. Polygynous marriages were common for high-status men. In many communities, men could pair with only one “primary” wife, typically someone of roughly equal social status, but could then add secondary wives, usually of lower social status.
Even at the core of the Roman Empire, intensive kin-based institutions remained central to social, political, and economic life. Roman families were organized around patriarchal patrilineages in which each man saw himself sandwiched in time between his great-grandfather and his great-grandsons. Even when they lived separately and had their own wives and children, adult men remained under the dominion of their fathers. Only male citizens without living fathers had full legal rights, control of family property, and access to tribunals; everyone else had to operate through the patriarch. It was within a father’s power to kill his slaves or children. Inheritance rights, incest prohibitions, and exemption from giving legal testimony all extended out, along the patrilineal branches, to the descendants of one’s father’s father’s father. Of course, the empire did develop legal mechanisms for inheritance by testament (wills), but during the pre-Christian period such testaments almost always followed custom and thus mostly came into play when matters were murky or disputes likely. Women remained under the control of either their father or their husband, although over time fathers increasingly retained control of their daughters even after marriage. Marriages were arranged (dowries paid) and adolescent brides went to reside in their husbands’ homes (patrilocal residence). Marriage was monogamous by default, but Roman men had few sexual constraints on their behavior save for those that might conflict with other Roman men. Divorce became common in the empire when elites began ending their daughters’ marriages in order to remarry them to ever more powerful families. Any children born during the marriage stayed with their father’s family, though the wife’s dowry returned with her to her father. As for cousin marriage, the details are complex, and both law and custom changed over time; but in short, cousin marriage in some form was socially acceptable, and some elites did marry their cousins in Roman society (Brutus, St. Melania, and Emperor Constantine’s four children). This continued until the Church started its relentless opposition.
THE MONKEY WRENCHES
Around 597 CE, Pope Gregory I—Gregory the Great—dispatched a mission to the Anglo-Saxon Kingdom of Kent in England, where King Æthelberht had married a Frankish Christian princess (eventually St. Bertha) some 17 years earlier. After only a few years, the missionary team had succeeded in converting Æthelberht, had begun to convert the rest of Kent, and had made plans to expand into nearby realms. These papal missionaries, unlike earlier Christian missionaries in places such as Ireland, had definite instructions regarding proper Christian marriage. Apparently, these policies did not go down well with the Anglo-Saxons, since the mission’s leader, Augustine (later known as St. Augustine of Canterbury), soon wrote to the pope seeking clarification. Augustine’s letter consisted of nine questions, four of which were focused on sex and marriage. Specifically, Augustine queried: (1) How distant must a relative be in order for a Christian marriage to be permissible (second cousins, third cousins, etc.)? (2) Can a man marry his stepmother or his brother’s wife? (3) Can two brothers marry two sisters? (4) Can a man receive Communion after a sex dream?
Pope Gregory responded to each question in turn. To the first, after acknowledging its legality under Roman law, Gregory affirmed that first cousins, and certainly not anyone closer, were strictly prohibited from marrying. He then also confirmed that a man could not marry his stepmother or his dead brother’s wife (no levirate marriage), even if they weren’t related by blood. Although these responses meant that Augustine had his work cut out for him, the reply wasn’t all bad news. The pope was fine with a pair of brothers marrying a pair of sisters, as long as the sets of siblings weren’t related.
Almost two centuries later, in 786, a papal commission again arrived in England, this time to assess the progress on Christianizing the Anglo-Saxons. Their report indicates that, although many had been baptized, there were serious issues among the faithful surrounding (1) incest (i.e., cousin marriage) and (2) polygyny. To uproot these stubborn customs, the Church promulgated the notion of “illegitimate children,” which stripped the inheritance rights from all children except those born within legal—i.e., Christian—marriages. Prior to this, as in many societies, the children of secondary wives in polygynous unions had possessed some inheritance rights. For royalty, the sons of secondary wives could be “raised up” to succeed their father as king, especially if the king’s primary wife was childless. Fighting this, by promoting the notion of “illegitimacy” and endowing itself with the power to determine who is legitimately married, the Church had seized a powerful lever of influence. These interventions made it substantially less appealing for cousins to marry or for women to become secondary wives.
Imposing these policies took centuries, in part because enforcement on the ground was so difficult. Throughout the ninth century, popes and other churchmen continued to complain to Anglo-Saxon kings about incest, polygyny, and illegitimacy, as well as the crime of having sex with nuns. In response, the Church could and sometimes did excommunicate elite men for marrying multiple women. By about 1000 CE, through its relentless efforts, the Church had largely prevailed in reshaping Anglo-Saxon (English) kinship.
The Anglo-Saxon mission is just one example of a much broader effort that reaches back before the fall of the Western Roman Empire (476 CE). Beginning in the fourth century, the Church and the newly Christian Empire began to lay down a series of new policies, again in fits and starts, that gradually corroded the pillars that supported intensive kinship. Keep in mind, however, that there is no single coherent program here, at least in the beginning. Things look scattershot and idiosyncratic for centuries; but slowly, the successful bits and pieces coalesced into what I’ll call the Church’s Marriage and Family Program—the MFP.
In undermining the intensive kin-based institutions in Europe, the MFP:
1. Prohibited marriage to blood relatives. These prohibitions were gradually extended to include quite distant relatives, up to sixth cousins. This essentially tabooed marriage or sex between those who shared one or more of their 128 great-great-great-great-great- grandparents.
2. Prohibited marriage to affinal kin within the circle of tabooed blood relatives. If your husband died, you couldn’t then marry his brother, your brother-in-law. In the eyes of the Church, your husband’s brother became like your real brother (incest!).
3. Prohibited polygynous marriage, including the taking of secondary wives, as well as the use of sex slaves and publicly supported brothels. Brothels were both legal and common in the Roman Empire, which may explain why Latin has 25 words for “prostitute.”
4. Prohibited marriage to non-Christians (unless they have converted).
5. Created spiritual kinship, which established the institution of godparents. This institution provided a means to form new social bonds to care for children. Of course, you couldn’t marry or have sex with spiritual kinfolk.
6. Discouraged the adoption of children. Mothers were to care for their own children; if they couldn’t, the Church or godparents would provide.
7. Required both the bride and groom to publicly consent (“I do”) to marriage. This suppressed arranged marriages and began to hitch marriage more firmly to romantic love.
8. Encouraged, and sometimes required, newly married couples to set up independent households—neolocal residence. The Church also encouraged the use of traditional marriage payments (e.g., dowry) to help fund this new residence.
9. Encouraged the individual ownership of property (land) and inheritance by personal testament. This meant that individuals could personally decide where their property went after their death.
To anyone other than an anthropologist, this might all sound boring or inconsequential, hardly the spark that ignited the blaze of Western civilization or the source of a major shift in people’s psychology. However, by looking more closely, we can see how the Church’s policies threw a barrage of monkey wrenches into the machinery of intensive kinship while simultaneously catalyzing its own spread. We’ll first look at how the Church dismantled traditional marriage, then consider how it sapped the vigor of Europe’s clans and kindreds, and finally see how it got rich on death, inheritance, and the afterlife.
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Downstream Transformations
As their intensive kin-based institutions dissolved, medieval Europeans became increasingly free to move, both relationally and residentially. Released from family obligations and inherited interdependence, individuals began to choose their own associates—their friends, spouses, business partners, and even patrons—and construct their own relational networks. Relational freedom spurred residential mobility, as individuals and nuclear families relocated to new lands and growing urban communities. This opened a door to the development and spread of voluntary associations, including new religious organizations as well as novel institutions such as charter towns, professional guilds, and universities. Such developments, underpinned by the psychological changes that I’ll highlight over the next seven chapters, ushered in the Urban, Commercial, and Legal Revolutions of the High Middle Ages.
The impact of societal change on the Church itself is interesting, as it represents a kind of feedback between the social and psychological shifts wrought by the MFP and the subsequent evolution of Catholic institutions. For example, the early monasteries in Anglo-Saxon England, before Pope Gregory’s team arrived around 600 CE, tended to be family affairs. The offices of abbot and abbess passed among brothers or from mother to daughter. In Ireland, these practices continued for centuries, as monasteries were run by wealthy Irish clans and passed down as communal property. However, the destruction of kin-based institutions, combined with the eventual delegitimization of priests’ children, gradually suppressed the strong intrusion of intensive kinship into the Church’s organizations. Many monasteries required aspiring monks to cut their kin ties as a condition of membership, making them choose between the Church and their families. Beginning with Cluny Abbey (910 CE) and accelerating with the emergence of the Cistercian Order (1098 CE), monasteries became less like clan businesses and more like NGOs, with the democratic election of abbots, written charters, and a hierarchical franchise structure that began to balance local independence with centralized authority.
The Church’s MFP reshaped the European family in a process that was largely complete 500 years ago. But does this really influence psychology today? Does growing up in less intensive kin-based institutions influence our motivations, perceptions, emotions, thinking styles, and self-concepts in significant ways? Is there a way to trace contemporary psychological variation back to the Church?
Psychological Differences
Families, and the Church Families represent the first institution we encounter upon arriving in the world, and, in most societies until recently, they have provided the central organizing framework for most people’s lives. So, it makes sense that they might play a foundational role in shaping our minds and behavior. In Chapter 1, I showed global patterns of psychological variation in domains ranging from individualism, conformity, and guilt to impersonal trust, analytical thinking, and the use of intentionality in moral judgments. Here, I begin to lay down the evidence that this psychological variation arises, in part, as our minds adapt and calibrate to the culturally constructed environments we confront, especially while growing up. We’ll examine how intensive kin-based institutions influence people’s psychology and, more specifically, how the Church’s dismantling of intensive kinship in medieval Europe inadvertently pushed Europeans, and later populations on other continents, toward a WEIRDer psychology.
To accomplish this, I’ll first lay out two ways of measuring the intensity of kin-based institutions for different ethnolinguistic groups and countries around the world. Then, using a wide-angle lens, I’ll show that kinship intensity can explain significant chunks of the cross-national psychological variation highlighted in Chapter 1. You’ll see that the weaker a population’s traditional kin-based institutions, the WEIRDer their psychology is today. Next, I’ll use the historical spread of the Church to create a measure of the duration of the Marriage and Family Program for every country in the world. Think of this as a time-release dosage of the MFP, measured in centuries of exposure to the Church. Using this historical dosage measure, we’ll first see that the stronger the MFP dosage ingested by a population, the weaker their kin-based institutions. Finally, we’ll directly connect these MFP dosages to contemporary psychological differences. Strikingly, the stronger the historical MFP dosage for a population, the WEIRDer their psychology is today.
In the next chapter, I’ll focus on the psychological variation within Europe, and even within European countries, as well as within China and India. These analyses not only confirm the expected relationships between psychological variation and both kinship intensity and the Church but should also fully immunize you against setting up the dichotomy of West vs. the Rest, or WEIRD vs. non-WEIRD in your mind. We are not observing fixed or essential differences among peoples but watching an ongoing cultural evolutionary process—influenced by multiple factors—playing out across geography and over centuries. Kinship Intensity and Psychology
Law, Science, and Religion
I think I can see the whole destiny of America contained in the first Puritan who landed on those shores, as that of the whole human race in the first man.
—Alexis de Tocqueville, Democracy in America (1835)
Western law, science, democratic government, and European religions have spread around the globe over the last few centuries. Even in countries without much real democracy or broad political representation, autocratic governments now often put on a big show that involves voting, elections, political parties, and campaigns. In places where the rule of law is weak, there are still written statutes and even inspiring constitutions that look like what you find in the United States, the United Kingdom, Germany, and France. Similarly, whenever I’ve traveled to remote communities, from Amazonia to the Pacific, I’ve found small Protestant congregations reading Bibles translated into the local languages. Where did these potent formal institutions and pervasive religions come from?
Many believe that these grand institutions, the bequests of Western civilization, represent the products of reason and the rise of rationality. These institutions—the rationalists argue—are what you get once you strip away Church dogma and apply “reason.” This is true even of Protestantism: many believed, and some continue to hold, that (some version of) Protestantism is what you get if you apply reason to the truths expressed in the Bible and toss away corrupt Church traditions. To the contrary, I would like to suggest a central role for the ongoing psychological changes wrought by cultural evolution during the Middle Ages—by the demolition of Europe’s kin-based institutions (Chapters 5–8), the expansion of impersonal markets (Chapter 9), the rise of domesticated forms of intergroup competition (Chapter 10), and the growth of a broad, mobile division of labor in urban centers (Chapter 11). The WEIRDer psychology that was emerging in fragmented communities across Europe, along with the accompanying changes in social norms, made people in these populations more likely to devise, endorse, and adopt particular kinds of ideas, laws, rules, policies, beliefs, practices, and arguments. Many modern ideas about law, government, science, philosophy, art, and religion that would have been “unthinkable,” aversive, or nonintuitive to people in most complex societies over most of human history began to “fit” the emerging proto-WEIRD psychology in medieval and Early Modern Europe. In many cases, these new ideas, laws, and policies were filtered and selected by relentless intergroup competition between voluntary associations, including among cities, guilds, universities, monasteries, scientific associations, and eventually territorial states.
Mapping the myriad connections and interactions between these societal developments and people’s changing perceptions, motivations, worldviews, and decision biases could easily fill volumes. My goal here, however, is more modest. I want to illustrate how an increasingly WEIRD psychology likely midwifed a few of the quintessentially Western formal institutions that came to dominate the legal, political, scientific, and religious domains of life in the latter half of the second millennium.
To warm up, let’s consider four aspects of WEIRD psychology that likely had broad influences on the formal institutions built in Europe during the second millennium of the Common Era.
1. Analytic thinking: To better navigate a world of individuals without dense social interconnections, people increasingly thought about the world more analytically and less holistically/relationally. More analytically oriented thinkers prefer to explain things by assigning individuals, cases, situations, or objects to discrete categories, often associated with specific properties, rather than by focusing on the relationships between individuals, cases, etc. The behavior of individuals or objects can then be analytically explained by their properties or category memberships (e.g., “it’s an electron”; “he’s an extrovert”). Troubled by contradictions, the more analytically minded seek out higher- or lower-level categories or distinctions to “resolve” them. By contrast, holistically oriented thinkers either don’t see contradictions or embrace them. In Europe, analytical approaches gradually came to be thought of as superior to more holistic approaches. That is, they became normatively correct and highly valued.
2. Internal attributions: As the key substrates of social life shifted from relationships to individuals, thinkers increasingly highlighted the relevance of individuals’ internal attributes. This included stable traits like dispositions, preferences, and personalities as well as mental states like beliefs and intentions. Soon lawyers and theologians even began to imagine that individuals had “rights.”
3. Independence and nonconformity: Spurred by incentives to cultivate their own uniqueness, people’s reverence for venerable traditions, ancient wisdom, and wise elders ebbed away. For good evolutionary reasons, humans everywhere tend to conform to peers, defer to their seniors, and follow enduring traditions; but, the incentives of a society with weak kin ties and impersonal markets pushed hard against this, favoring individualism, independence, and nonconformity, not to mention overconfidence and self-promotion.
4. Impersonal prosociality: As life was increasingly governed by impersonal norms for dealing with nonrelations or strangers, people came to prefer impartial rules and impersonal laws that applied to those in their groups or communities (their cities, guilds, monasteries, etc.) independent of social relationships, tribal identity, or social class. Of course, we shouldn’t confuse these inchoate inklings with the full-blown liberal principles of rights, equality, or impartiality in the modern world.
These and related aspects of psychology were taking hold in small but influential populations scattered across western Europe by the High Middle Ages.
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The Dark Matter of History
Humans are an intensely cultural species. For over a million years, the products of cumulative cultural evolution—our complex technologies, languages, and institutions—have driven our genetic evolution, shaping not only our digestive systems, teeth, feet, and shoulders but also our brains and psychology. The centrality of cultural change meant that, generation after generation, young learners had to adapt and calibrate their minds and bodies to an ever-shifting landscape of sharing norms, food taboos, gender roles, technical demands (e.g., projectile weapons and underwater foraging), and grammatical conventions. At the same time, cultural evolution has favored an arsenal of mind hacks, including rituals, socialization practices (e.g., bedtime stories), and games, that mold people’s psychology in ways that allow them to navigate their culturally constructed worlds more effectively. The consequence of this culture-gene co-evolutionary process is that to understand people’s psychology we must consider not only our genetic inheritance but also how our minds have adapted ontogenetically and culturally to the local technologies and institutions—present or even a few generations past. Thus, we should expect a rich array of diverse cultural psychologies to go along with disparate societies. The cultural evolution of psychology is the dark matter that flows behind the scenes throughout history.
To build up an understanding of the interaction between institutions and psychology, I began by drilling down to focus on our species’ oldest and most fundamental institutions—those related to kinship and religion. Given their anchoring in our species’ evolved psychology, it’s not surprising that kin-based institutions culturally evolved as the primary way that mobile hunter-gatherers organize themselves and stretch out their cooperative networks. However, after the origins of sedentary agriculture, the need to control territory in the face of fierce intergroup competition drove the intensification of kin-based institutions, leading to the norm clusters that organize clans, cousin marriage, corporate ownership, patrilocal residence, segmentary lineages, and ancestor worship. As societies scaled up, the most successful political institutions remained heavily entwined with kinship. Even after the emergence of premodern states, with their military forces and tax-collecting bureaucracies, kin-based institutions still dominated life among both the elite and the lower strata. All of this means that some of the contemporary psychological variation we observe can be traced, through a variety of pathways, back to the ecological, climatic, and biogeographic factors that influenced the emergence of kin-based institutions and states.
Alongside kinship, both religions and rituals have also been culturally evolving over eons to harness aspects of our species’ evolved psychology in ways that expand the social sphere and foster cooperation in larger groups. However, the emergence of diverse universalizing religions with the development of cosmopolitan empires provided new opportunities for cultural evolution to “experiment with” a variety of divine prescriptions and prohibitions related to marriage and the family. Some universalizing faiths endorsed marriage to close relatives (Zoroastrianism), while other faiths forbade previously common unions, such as those between cousins or affines. Similarly, some religions permitted men to marry as many wives as they wanted to (or could), while others limited them to only four and required equality among the wives (Islam). By the outset of the first millennia of the Common Era, the Roman Empire was a bubbling cauldron of religious competition that included the old Roman state religion, Judaism, Zoroastrianism, Mithraism, a potpourri of Christian faiths, and a panoply of local religions. From this cauldron, one strain of Christianity stumbled upon a peculiar set of taboos, prohibitions, and prescriptions regarding marriage and the family that eventually crystallized into the Church’s Marriage and Family Program.
These prohibitions and prescriptions, which were infused into Christianizing populations under the Western Church over many centuries (arrow A in Figure 14.1), altered people’s social lives (arrow B) and psychology (arrow C) by demolishing intensive kin-based organizations. These changes would have favored a psychology that was more individualistic, analytically oriented, guilt-ridden, and intention-focused (in judging others) but less bound by tradition, elder authority, and general conformity. The elimination of polygynous marriage and the tightening of constraints on male sexuality may also have inhibited male status-seeking and competition, which would have suppressed zero-sum thinking, impatience, and risk-seeking.
The social and psychological changes driven by the breakdown of intensive kinship opened the door to rising urbanization, expanding impersonal markets (arrows D and E), and competing voluntary associations like charter towns, guilds, and universities. By facilitating and enforcing impersonal interactions in various ways, urban centers and commercial markets further stimulated impersonal prosociality and impartial rule-following while incentivizing personal attributes like patience, positive-sum thinking, self-regulation, and time thrift (arrows F and G). By producing a growing division of labor, within which an expanding class of individuals could select their occupations and social niches, these new social environments may have fostered more differentiated personality profiles—expanding eventually into the WEIRD-5—and strengthened people’s inclinations to think in dispositional ways about other individuals and groups.
The quiet fermentation of these psychological and social changes influenced the formation of governments, laws, religious faiths, and economic institutions in the latter half of the Middle Ages and beyond. Creating laws, for example, that focus on individuals and their properties (“rights”) just makes sense if one lives in communities with weak family ties, substantial relational mobility, and a developing individualistic psychology that parses the world in dispositional ways (“she’s trustworthy”). By contrast, if one lives in a community where relational ties are central and people are primarily judged by their social and family connections, building law and government around individual rights doesn’t seem like common sense. It doesn’t “fit” people’s psychological inclinations.
FIGURE 14.1. Outline of the main processes described in this book.
In the last chapter, I examined how cultural evolution—in the wake of the transformation of European kinship and rising urbanization—expanded Christendom’s collective brain and altered key aspects of people’s psychology in ways that would have catalyzed innovation, suppressed fertility, and propelled economic growth. We saw how these ongoing social and psychological changes gradually opened the flow of ideas, beliefs, practices, and techniques within a sprawling network of interconnected minds, each of which was motivated to produce new insights and challenge old assumptions. This occurred in myriad ways, including through the diffusion of literacy (due to Protestantism), the proliferation of scientific societies, and the accelerating flow of artisans, scholars, and merchants through far-flung European cities and towns. This expanding collective brain sparked the Enlightenment, drove the Industrial Revolution, and continues to propel economic growth around the globe.
Now, with this summary in mind, let’s return to the three core questions that I posed back in Chapter 1:
1. How can we explain global psychological variation, and specifically the variation highlighted throughout this book (Table 1.1)?
Answer: To explain psychological variation broadly, we need to examine how history has unfolded in different ways in different places and consider the co-evolution of people’s minds with different institutions, technologies, and languages. Targeting the psychological patterns highlighted in Table 1.1, I focused on the evolution of institutions related to (1) intensive kinship, (2) impersonal markets and urbanization, (3) competition among voluntary associations, and (4) complex divisions of labor with substantial individual mobility.
2. Why are WEIRD societies particularly unusual, so often occupying the extreme ends of global distributions of psychology and behavior?
Answer: The sect of Christianity that evolved into the Roman Catholic Church stumbled onto a collection of marriage and family policies that demolished Europe’s intensive kin-based institutions. This grassroots transformation of social life propelled these populations down a previously inaccessible pathway of societal evolution and opened the door to the rise of voluntary associations, impersonal markets, free cities, and so on.
3. What role did these differences play in the Industrial Revolution and in the global expansion of Europe during the last few centuries?
Answer: By the High Middle Ages, the social and psychological shifts induced by the Church had made some European communities susceptible to notions of individual rights, personal accountability, abstract principles, universal laws, and the centrality of mental states. This fertilized the psychological soil for the growth of representative governments, constitutional legitimacy, and individualistic religious faiths as well as the rise of Western law and science. These changes accelerated the ongoing social and psychological transformations that energized innovation and economic growth.