The WEIRDest People in the World

The WEIRDest People in the World Plot Summary

Introduction

Imagine standing in a small village in 8th century Europe, witnessing a scene that would change the course of human history: a local priest is refusing to bless a marriage between cousins, a practice that had been common throughout human societies for millennia. This seemingly minor religious restriction was part of a revolutionary program that would transform European family structures and, eventually, reshape human psychology itself. The Catholic Church's systematic dismantling of traditional kinship systems would set Western civilization on a unique trajectory, creating societies characterized by individualism, impersonal cooperation, and analytical thinking. This historical journey explores how a religious institution's marriage policies inadvertently created the psychological foundations for modern markets, democracy, and science. Why do Western societies display such distinctive psychological traits compared to the rest of the world? How did these differences emerge, and what role did they play in the rise of modern institutions? By tracing the evolution of European family structures from the early Middle Ages through the Industrial Revolution, we gain profound insights into the deep cultural roots of modern society. Whether you're curious about why Western nations developed particular economic and political systems or seeking to understand global cultural differences in our interconnected world, this exploration reveals the hidden forces that shaped Western civilization and continue to influence global development today.

Chapter 1: The Church's Marriage Program: Dismantling European Kinship (500-1200)

In the aftermath of the Roman Empire's collapse, Europe was organized much like the rest of the world - through intensive kinship networks where extended families controlled resources, provided security, and determined individual identity. But between 500 and 1200 CE, the Western Church launched what scholars now call the Marriage and Family Program (MFP), a systematic campaign to transform European family structures in ways unprecedented in human history. The Church's program began with increasingly strict prohibitions against cousin marriage. While most societies throughout history permitted or even encouraged marriage between cousins to strengthen family alliances, the Church gradually expanded its incest taboos to unprecedented levels. By the 11th century, these prohibitions extended to sixth cousins - effectively banning marriage between people who shared even one of their 128 great-great-great-great-great-grandparents. The Church also banned practices common throughout the world: polygamy, concubinage, adoption, divorce, and remarriage. When Pope Gregory I dispatched missionaries to Anglo-Saxon England in 597 CE, they carried these revolutionary marriage policies with them, often encountering resistance from local populations accustomed to traditional marriage practices. The enforcement of these policies was remarkably comprehensive. The Church threatened spiritual sanctions like excommunication and eternal damnation, while secular authorities, particularly during the Carolingian Empire under Charlemagne, imposed legal punishments for violations. In 596 CE, the Merovingian king Childebert II decreed the death penalty for those who married their stepmothers. This alliance between Church and state created a powerful mechanism for transforming European family structures, particularly in regions that had been part of the Carolingian Empire - modern France, western Germany, northern Italy, and parts of England. The consequences of this transformation were profound. By prohibiting cousin marriage, the Church made it impossible for families to maintain their traditional networks of alliances. By banning adoption and remarriage, it prevented lineages without biological heirs from continuing. By requiring couples to establish independent households, it weakened extended family compounds. The Church itself benefited enormously from these changes - by 900 CE, it owned approximately one-third of the cultivated land in western Europe, much of it acquired through bequests from Christians who died without heirs. This dismantling of intensive kinship created something unprecedented - a society where individuals were increasingly free from the constraints of extended family obligations. Released from these bonds, Europeans began developing new forms of social organization based on voluntary association rather than blood ties. This opened the door to novel institutions like charter towns, professional guilds, and universities - laying the groundwork for what would eventually become modern Western society with its distinctive psychological patterns and institutional structures.

Chapter 2: From Clans to Individuals: Psychological Transformation in Medieval Europe

Between 1000 and 1300 CE, as the Church's marriage policies gradually dissolved traditional kinship structures, a profound psychological transformation began unfolding across Europe. In societies with strong kin-based institutions, individuals are embedded in dense networks of inherited relationships that shape their identity and behavior. Success depends on navigating these networks, conforming to group expectations, and maintaining family honor. But as these structures weakened in Europe, a distinctly different psychology began to emerge. Without the constraints of intensive kinship, medieval Europeans increasingly needed to forge beneficial relationships based on their personal attributes rather than family connections. This fostered what psychologists call "dispositional thinking" - the tendency to view people as having consistent traits across contexts rather than behaving according to relational roles. Historical records show this shift in how people described themselves and others, with increasing emphasis on personal qualities rather than family affiliations. By the 13th century, European literature like Chaucer's Canterbury Tales portrayed characters defined by individual traits rather than primarily by their place in kinship networks. The primary emotional regulator in human behavior also shifted during this period. In societies with intensive kinship, shame - the fear of public judgment by one's community - serves as the main mechanism of social control. As kinship bonds weakened in Europe, guilt - an internalized moral compass that operates even without public scrutiny - became increasingly important. This psychological shift is evident in medieval religious practices like private confession, which became mandatory for all Christians following the Fourth Lateran Council in 1215. The emphasis on examining one's conscience and feeling personal remorse for transgressions reflected and reinforced this emerging guilt-oriented psychology. Trust patterns also transformed dramatically. In traditional kin-based societies, trust is primarily extended to family members and close relations. As Europeans were forced to look beyond kin groups for marriage partners, economic opportunities, and social support, they developed greater capacity for "impersonal trust" - the willingness to cooperate with strangers based on shared norms rather than personal relationships. This psychological adaptation proved crucial for the development of markets, urban communities, and eventually modern institutions. By 1300, these psychological shifts had created substantial differences between Europeans in regions with longer Church exposure and populations elsewhere in the world. Europeans were becoming more individualistic, less conformist, more analytical in their thinking, and more willing to cooperate with strangers according to abstract principles. These psychological patterns weren't simply the result of economic or technological changes but emerged directly from the transformation of family structures initiated by the Church's marriage policies. The stage was set for the institutional innovations of the late medieval and early modern periods that would eventually position Europe for unprecedented economic and political developments.

Chapter 3: The European Marriage Pattern and Its Economic Consequences

By the late medieval period, a distinctive European Marriage Pattern had emerged in regions with long exposure to the Church's marriage policies. This pattern, most pronounced in northwestern Europe, would have far-reaching consequences for economic development and social organization. Unlike marriage systems in most human societies, which featured early marriage (often in the teens), universal marriage for women, and extended family households, the European pattern was strikingly different. The European Marriage Pattern was characterized by several key features that distinguished it from global norms. First, both men and women married remarkably late, with average ages often in the mid-20s, compared to the teenage marriages common elsewhere. Second, a significant percentage of women (15-25%) never married at all, compared to just 1-2% in traditional China or India. Third, newly married couples typically established independent households rather than joining extended family compounds. Fourth, families were smaller, with fewer children per household. Finally, young people often experienced a "premarital labor period," working as servants or apprentices in other households to earn money and learn skills before marriage. These marriage patterns created several important economic dynamics. Late marriage and high rates of celibacy served as a form of population control, helping to balance resources with population in an era before modern contraception. The need to establish independent households before marriage encouraged saving and capital accumulation, as young people worked for years to gather resources. The premarital labor period created a flexible labor market and facilitated skill transfer across households and communities. Women's relatively high status and economic participation expanded the productive workforce. The economic consequences were substantial. In regions where the European Marriage Pattern was strongest, we see earlier development of labor markets, higher rates of literacy, greater urbanization, and more rapid industrialization. Historical economist Jan de Vries has documented how northwestern European households increasingly participated in market-oriented production from the 16th century onward, creating what he calls "industriousness" before industrialization. This pattern of household economic behavior, rooted in the distinctive marriage system, helped lay the groundwork for later industrial development. By the 18th century, these family patterns had positioned northwestern Europe for unprecedented economic transformation. The regions with the strongest European Marriage Pattern - England, the Netherlands, northern France, and parts of Germany - would become the early centers of the Industrial Revolution. The psychological traits fostered by these family patterns - individualism, future orientation, and comfort with impersonal exchange - proved particularly well-suited for market economies and industrial organization. What had begun as a religious program to reform marriage had inadvertently created social and psychological conditions that would transform the global economy.

Chapter 4: Measuring Church Influence: Evidence Across Cultures and Regions

To systematically test the relationship between Church exposure, kinship intensity, and psychological differences, researchers have developed innovative methods for measuring these variables across diverse populations. The results provide compelling evidence for the Church's transformative impact on human psychology, revealing patterns that help explain global variations in economic development, political institutions, and social trust. One approach uses the Kinship Intensity Index (KII), which combines anthropological data on cousin marriage, nuclear families, bilateral inheritance, neolocal residence, and monogamous marriage. When mapped globally, this index shows that Western European populations and their offshoots have exceptionally weak kinship intensity compared to most other societies. Another key measure focuses specifically on cousin marriage rates. Cross-cultural data show that about 10% of marriages worldwide are between cousins or other close relatives. In the Middle East and parts of Africa, these rates exceed 30-50%, while in Western countries, they're typically below 0.2% - a dramatic difference that reflects centuries of divergent family systems. To measure Church exposure, researchers tracked the expansion of bishoprics across Europe from 500 to 1500 CE, calculating "MFP dosages" for different regions. Statistical analyses reveal striking relationships between these variables. The longer a population was exposed to the Church, the weaker their kin-based institutions. Each century of Western Church exposure is associated with a nearly 60% reduction in cousin marriage rates. Together, exposure to the Western and Orthodox Churches explains about 40% of global differences in kinship intensity and 62% of differences in cousin marriage rates. These relationships extend to psychology. Populations with longer Church exposure show less conformity, less adherence to tradition, more individualism, greater trust of strangers, more universalistic morality, and more analytical thinking. In laboratory experiments, people from societies with stronger kinship ties show greater conformity to group opinions, more concern with tradition and obedience, stronger in-group loyalty, and less trust of strangers. When making moral judgments, they focus less on intentions and more on outcomes and relationships. The Italian case provides particularly compelling evidence. Northern Italy, which has been under Western Church influence since the early Middle Ages, shows almost no cousin marriage in modern times. Southern Italy and Sicily, which were variously under Byzantine, Muslim, and Norman rule before being fully incorporated under papal hierarchy, maintained significantly higher rates of cousin marriage into the 20th century. These differences in kinship intensity correlate with contemporary variations in blood donation rates, corruption, and economic development - with northern regions showing greater impersonal prosociality and stronger formal institutions. These patterns hold even when controlling for factors like geography, climate, wealth, education, and current religious beliefs, suggesting that the Church's marriage policies had lasting effects on psychology independent of other historical factors. The evidence points to a remarkable conclusion: a religious institution's approach to marriage and family inadvertently reshaped human psychology in ways that would profoundly influence the development of modern institutions.

Chapter 5: The Rise of Voluntary Associations and Impersonal Institutions

As kinship bonds weakened across medieval Europe, a vacuum emerged in social organization that would be filled by a revolutionary development: voluntary associations based on common interests rather than blood ties. Between 1000 and 1500 CE, Europeans created an unprecedented array of self-governing organizations that would form the institutional foundation for later economic and political developments. Cities led this institutional revolution. Unlike urban centers in other civilizations, which typically remained under imperial or aristocratic control, European cities developed remarkable autonomy. Beginning in northern Italy and spreading northward, urban communities formed governing councils through public oaths sworn before local bishops. By 1200, hundreds of European cities had established town councils, written legal codes, and systems of collective decision-making. The Magdeburg Law, originating in a German city, spread to over 1,000 cities across Central and Eastern Europe, creating a network of self-governing urban communities with similar institutional frameworks. These charter towns attracted migrants from the countryside with promises of freedom from feudal obligations - as the German saying went, "Stadtluft macht frei" (city air makes you free). Alongside cities, other voluntary associations proliferated. Merchant guilds united traders across kinship lines, establishing standardized contracts and impersonal exchange norms. Craft guilds regulated production quality while providing members with mutual aid and social insurance. Universities emerged as self-governing corporations of scholars and students, with institutions like Bologna (founded 1088) and Paris (c.1150) establishing models that spread across Europe. Religious orders created communities bound by shared commitments rather than family relationships, with the Cistercian Order alone counting 750 houses by the 15th century. These associations shared crucial features that distinguished them from traditional social organizations. First, they were voluntary - individuals could join and leave by choice rather than birth. Second, they were governed by explicit rules rather than implicit customs. Third, they treated members as individuals with specific rights and obligations rather than as representatives of kin groups. Fourth, they often featured representative governance, with leaders elected by members rather than inheriting positions. The competition among these voluntary associations drove cultural evolution in powerful ways. Successful organizational forms were copied and modified, spreading innovations in governance, commerce, and education. Cities competed to attract skilled artisans by offering better privileges. Universities competed for renowned teachers who could move to obtain greater intellectual freedom. This institutional ecosystem created unprecedented social flexibility and mobility, allowing individuals to construct their own social networks based on interests and abilities rather than inherited connections. By 1500, Europe had developed an institutional environment fundamentally different from those in other complex societies. This network of competing voluntary associations fostered greater mobility, innovation, and impersonal cooperation - creating the foundation for later developments in science, commerce, and governance that would eventually position Europe for global influence.

Chapter 6: WEIRD Psychology: How Church Policies Shaped Western Minds

The distinctive trajectory of Western civilization can be traced to a specific psychological transformation that began in the early medieval period with the Church's dismantling of intensive kinship systems. By the early modern era, Europeans in regions with longer Church exposure had developed what psychologists now call WEIRD psychology - Western, Educated, Individualistic, Rich, and Democratic. This psychological package includes strong individualism, analytical thinking, impersonal prosociality, universal morality, and guilt-based self-regulation. These psychological traits proved remarkably advantageous for certain forms of social and economic organization. Individualism fostered innovation by encouraging people to distinguish themselves through novel contributions. Analytical thinking facilitated scientific discovery by breaking problems into component parts and identifying abstract principles. Impersonal prosociality enabled complex organizations beyond kinship groups, supporting markets and bureaucracies. Universal morality provided foundations for impartial legal systems. Guilt-based self-regulation reduced the need for external monitoring, lowering transaction costs in economic and political interactions. The global expansion of European powers from the 15th century onward spread these institutional and psychological patterns to other continents. In settler colonies like North America, Australia, and New Zealand, WEIRD psychology and its associated institutions took root and flourished, creating societies that were even more individualistic and market-oriented than their European origins. Through colonialism, trade, and cultural influence, elements of this package have since diffused globally, though often in hybrid forms that blend with local traditions. Cross-cultural psychology research confirms these psychological differences persist today. People from WEIRD societies show greater visual attention to focal objects rather than backgrounds, stronger tendencies to categorize objects by properties rather than relationships, more emphasis on personal choice, greater trust of strangers, and stronger focus on intentions rather than outcomes in moral judgments. These differences aren't superficial but reflect fundamental variations in perception, cognition, and social orientation. Understanding the historical origins of WEIRD psychology has important implications for our increasingly interconnected world. It suggests that attempts to transplant Western institutions without understanding their psychological foundations often produce unexpected results. Democratic constitutions, market regulations, and legal systems that evolved in low-kinship Western environments function differently when implemented in societies with stronger relational networks. It also reveals that non-Western approaches to social organization aren't simply "traditional" forms waiting to be modernized, but represent alternative adaptations with their own strengths and weaknesses. This historical perspective offers both cultural humility and practical insight. Rather than assuming universal psychological patterns or expecting rapid convergence, we might better recognize the deep cultural-evolutionary processes that shape human psychology and the institutions it creates. The most successful global institutions will likely be those that can bridge different psychological orientations, combining the impersonal principles that emerged from Western history with the relational approaches that remain powerful across much of the world.

Summary

The transformation of European family structures under the Catholic Church's marriage policies represents one of history's most consequential yet overlooked developments. Beginning in the early medieval period, the Church systematically dismantled traditional kinship systems through prohibitions against cousin marriage, polygamy, adoption, and other practices common throughout human history. This institutional shock gradually created societies characterized by nuclear families, weak extended kinship ties, and high individual mobility. The psychological consequences were profound: Europeans in regions with longer Church exposure developed greater individualism, more analytical thinking, stronger impersonal trust, and more universalistic morality - traits that would eventually support markets, constitutional governments, scientific inquiry, and industrial innovation. This historical journey offers crucial insights for our contemporary world. It suggests that formal institutions like constitutions, markets, and legal systems don't function independently of the psychological patterns of the populations they govern. When institutions developed in one psychological context are transplanted to societies with different psychological foundations, the results often disappoint expectations. Rather than assuming universal psychological patterns or expecting rapid convergence, we might better recognize the deep cultural-evolutionary processes that shape human psychology and the institutions it creates. This perspective encourages both greater cultural humility and more nuanced approaches to institutional development, acknowledging that effective governance requires alignment between formal structures and the psychological patterns of those they serve. By understanding how history shaped our minds, we gain valuable perspective on the challenges and opportunities of our increasingly interconnected global society.

About Author

Loading...

Joseph Henrich

Joseph Henrich is an anthropologist. He is the Chair of the Department of Human Evolutionary Biology of Harvard University and a professor of the department.Joseph Henrich's research focuses on evolutionary approaches to psychology, decision-making and culture, and includes topics related to cultural learning, cultural evolution, culture-gene coevolution, human sociality, prestige, leadership, large-scale cooperation, religion and the emergence of complex human institutions. Methodologically, he integrates ethnographic tools from anthropology with experimental techniques drawn from psychology and economics. His area interests include Amazonia, Chile and Fiji.

Read more