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The WEIRDest People in the World: How the West Became Psychologically Peculiar and Particularly Prosperous

Author(s):Henrich, Joseph
Reviewer(s):Root, Hilton

Published by EH.Net (October 2020)

Joseph Henrich, The WEIRDest People in the World: How the West Became Psychologically Peculiar and Particularly Prosperous. New York: Farrar, Straus and Giroux, 2020. xxv + 680 pp. $31.50 (hardcover), ISBN: 978-0-374-17322-7.

Reviewed for EH.Net by Hilton Root, School of Policy and Government, George Mason University.



Harvard anthropologist Joseph Henrich’s latest book, The WEIRDest People in the World: How the West Became Psychologically Peculiar and Particularly Prosperous, differs from most contemporary scholarship in one big way. It tackles a cross-disciplinary topic and makes giant claims. Henrich asserts that the West became Educated, Industrialized, Rich, and Democratic owing to traits that have their genesis in a little appreciated tenet of early Christianity, that it is wrong for cousins to marry each other. Through “accidental genius,” the Church dismantled kin-based power networks in order to spread its own norms and institutions.

The book comprises three sections. The first describes the traits of WEIRD people; the second, how societies have always used religion to scale up, which builds on another book of his, The Secret of Our Success; the third, how the Catholic Church and its offshoot, Protestantism, shaped early institutions and psychology, paving the way for modernity.

Henrich claims that starting in the fourth century, the Roman Church assumed control of marriage by making the institution dependent on its blessing and banning cousin marriages. In great synods, it proclaimed the ban 88 times into the twentieth century.

What Henrich calls the Church’s “Marriage and Family Program” restructured medieval populations and directed the evolution of European society along a pathway no other society in world history has ever traveled. In another unforeseen consequence, it fertilized the West’s responsiveness to individualistic religious faith and eventually opened the doors for the Reformation, which split the Church and accelerated still more cultural changes that created modernity.

With its emphasis on personal responsibility for one’s salvation, the Reformation stressed literacy and the need to know the Bible, leading the Reformed states of Northwestern Europe to promote education. This was to have unintended consequences as well. As Henrich explains, recent clinical discoveries relate reading to alterations to brain tissue and connectivity that expand the capacity for analytical reasoning.

Henrich emphasizes that the Church did not foresee the long-term cultural changes its actions were to have, and he reiterates throughout the book that much of the downstream transformations the Church initiated — representative government, universal law, and democracy — were “accidental.” So why did the Church persist in defining incest, even up to the sixth cousins and widowed in-laws, pushing it far beyond other major religious denominations? Self-interest, he speculates. The Church competed for influence against tribal loyalties and intensive kin-based networks and institutions. It used the relentless taboos and punishments to weaken the traditional patriarchal authority and dissolve clan affinities, creating more opportunity for believers to devote themselves, their children, and their estates to the Church.

Henrich thus aligns himself with other scholars of Christianity, which sees the early Church as self-serving and aggressive in its pursuit of power. William Jack Goody (1983), a leading figure in cultural anthropology, makes this very point about the Church’s heirship policies.

If Henrich is correct, he is onto something big. His major discovery draws upon the research of two German historians, Karl Ubl (2008) and Michael Mitterauer (1991), along with papers that he worked on with other colleagues, and especially the econometric verification of George Mason economist Jonathan Schulz (2020).

The most widely known books on early Christianity place little emphasis on incest bans when discussing Church contributions to Western civilization. The proscriptions are also passed over by historians as being more aspirational than effectual. Late antiquity, which lasted into the seventh century, was a world in which monasteries were often owned by founding families; the sons of married priests followed them into office; and divorce and illicit marriages were rife. Christianity’s greatest impact was in its written laws that eventually took precedence over the oral diffusion of tribal customs on marriage and inheritance. Even so, it took centuries of Church influence to establish that the legality of marriage required ecclesiastical blessing. During the Early Medieval Period (500–1000), the supervision of an episcopate was not even sufficient to ensure celibacy of the priesthood. The ban forbidding divorce or the marriage between persons within prohibited degrees required repeated reaffirmation, suggesting that the Church faced a long uphill battle to enforce its rules.

Nevertheless, even if the incessant marriage and family campaign were merely aspirational, Henrich’s findings suggest that we need to change our thinking of the early Church. The aggressive pursuit of the marriage program cannot be explained as solely a result of narrow self-interest and self-aggrandizement, which Henrich explains as the absorption of Church leaders in their own institutional ambitions. It seems instead that its ideological zeal aimed to stem the polarization of the European population and the constant breakdown of order due to frequent war among the barbarian tribes and to ensure the very survival of Christendom as a kingdom, or society, of Christians. This interpretation of the cousin marriage ban would be more consistent with the research of Ubl and the synthesis of St. Augustine.

One of the great intellectual achievements of early Christianity addressed this polarization. St. Augustine’s City of God, was written in the early fifth century and links Church and state with war and peace, and with sex and marriage. It is an entreaty to the Catholic Church for a state that can act as an instrument of justice. In the fractured political reality of his era, the fourth and fifth centuries, a state built on top of kinship was not stable. A just state, Augustine reasoned, is a community bound by caritas, or agapē in Greek, love that is selfless and directed toward humankind.

Exogamy extends the scope of caritas Augustine (354–430 AD) writes: “Because siblings cannot marry … the separation of relationships extended universal love (caritas) to a greater number and enhanced the social life of human beings, among whom concord should be useful and honorable.” He advocates impediments on marriage to keep familial relationships separate from each other: “because of both the expansion of charity and the beauty of the church, it was instituted that marriage should not take place where there is already natural love, as among blood relations and people sharing a common parent, but only between non-kin” (Reynolds 2016, 340, 342).

Henrich’s genius and the source of his methodological originality reside in his application of contemporary social science to uncover universal laws, and to classify and categorize social reality in a context-free approach. He often works backward from outcomes to causes — for example, describing what European society might have been if the Church had not undertaken its marriage and family program. He draws comparisons with contemporary non-European societies that have retained more kinship-intensive ways of organizing. With cross-cultural empirical data, he illustrates these differences in terms of corruption, violence, obedience, business ethos, contributions to public goods, impersonal fairness, and receptivity to tradition, guilt, shame, and democracy. With this approach we can identify correlations not previously observed. The evidence strongly supports the importance of repressing “kinship intensity” in trajectories toward modernity.

Yet tracing causality without locating the mechanisms of transmission — the nuts and bolts of political history — is problematic. In the case of the marriage ban, it will take further research to resolve the question of intentionality and the ban’s diffusion across the continent. What we do not get from Henrich’s approach is the larger-system context or architecture that also defined Europe. We must understand how the Church as one network connected with other key actors and networks in European society and statecraft. It is not enough to know that the Church published edicts and proclamations unless we know how, when, where, and by whom they were put into practice all the way down to the parish level — another puzzle that seems well suited for Henrich’s consideration.

The Western Church from the fourth century found itself in a fragile geopolitical environment; the Roman empire was split between two capitals, and Church in the West was beset with political machinations from within and tension with the Eastern Church. Invading heathens made constant incursions from the north, east, and south. What made the Church-state dynamics of western Europe unique was its great wealth dating from the fourth-century, when the Emperor Constantine (306–337), hoping to unify the empire, transferred to the western Church the wealth of the pagan temples, making it the greatest landed proprietor in the world.

Nevertheless, Christendom needed an enduring partnership of Church and state to survive. In 800 Pope Leo III crowned Charlemagne (Charles I) as Emperor of the Holy Roman Empire. With Charlemagne both Europe’s most powerful ruler and the Church’s protector, the Church now gained great leverage over education, monastic life, and a large role in the management of civic relationships at the parish level. This alliance was to become the cultural scaffolding of the Middle Ages and from it the Church gained support in its campaign against incest. Charlemagne, Ubl tells us, wanted to diffuse the power of regional aristocracies by forcing them to marry out and thereby reduce the centrifugal forces causing divisiveness within the empire.

Feudal knights constituted another essential actor on Europe’s path to modernity. The knights, along with the monks and country friars, consumed a large portion of Europe’s surplus production. Feudalism, Europe’s nascent system of governance, sprang from the political arrangement designed to sustain the knights’ services to the monarch, which affected the economy as well as morality and aesthetics. This alliance was so critical that starting in the eleventh century, the Church developed special ceremonies to sanctify knighthood. A warrior girded with the belt of knighthood entered the church and placed his sword upon the altar as an offering. The promise to God of services of the sword bound the knight to perpetual service to the Church.

Moreover, Germanic society did not have to wait for the Church marriage ban to develop bonds beyond kinship. Among the Germanic tribes, loyalty to a chief was personal not tribal; chiefs attracted followers from many tribes, and when the claims of the lord conflicted with those of the kindred, duty to the lord would come first. Rather than opposing the Germanic principle of loyalty, the western Church willingly asserted that the binding force of duty was owed to a man’s lord and added sanctity to that oath (Whitelock 1952).

With Church support, the knights evolved into a noble class separated by blood ties from the rest of the population. In every country, the highest positions in the Church typically were preserved for the nobility, and great lords filled the church councils. Strengthening the hereditary rights of kings and knights, the Church embedded greater inequality into the system, the traces of which marked European social history until the early twentieth century. Only in passing does Henrich note that the Church did not apply the marriage rules on elite lineages with the same rigor as it did on peasant communities (p. 180). Elites remained embedded in intensive kin-based institutions. It took two centuries of absolutism and one of revolution to weaken the power and prestige of the aristocracy that the Church had reinforced.

The main shortcoming of Henrich’s analysis is its reliance on linear causality. Tracing an outcome, e.g., the distinctive psychology of Western society, to an original cause, the Church ban on cousins wedding, is in itself WEIRD. And his perspective is written for other WEIRD-minded folk who interpret causal pathways in history as proceeding in a straight line.

A different way to understand the Church’s role in European history is to view it as a social network that interacts and coevolves with other complex social networks. As a subsystem among other important subsystems (secular powers, towns, civil law, and royals, for example) that made up the larger system of the medieval West, it was the constant subject of the pull of those social forces around it, co-adapting within a changing environment (Root 2020), exerting sufficient influence, as events called for it, among the exalted monarchs or the most vulnerable village folk, to ensure its own continuity.

What makes the Church-state dynamics of Western Europe unique in world history is the considerable autonomy the former enjoyed because of its immense wealth. Its administrative capacity far exceeded that of the barbarian kings as it had become the repository of knowledge of Rome. This gave it great stature in a distributed system among other important subsystems, The Church had organizational capacity to mobilize and intellectual capacity to inspire, but it did not act alone. To succeed it needed to cooperate with Europe’s intermarried elites, especially the royal families. Being anointed by the episcopate, monarchs could claim eminence above all other lay leaders, and both the clerical and royal realms depended on the landed nobility to act locally and to recruit foot soldiers from the peasantry, from which the Church drew monks and parish priests.

As a chronicle of history, the narrative falls short, jumping from the fifth century to the High Middle Ages. Even so, the book makes a significant contribution to the study of what makes the West unique and will be a landmark of early twenty-first-century social science. It is persuasive that social psychologists have underestimated the degree to which western behavior once assumed to be universal is actually parochial. It illustrates the need for social psychologists to start to include people living in non-modern environments in their experiments — something Henrich has been doing since early in his career.

Henrich ambitiously tries to reunite economic anthropology with its cousin disciplines, economics and sociology, and places culture and social psychology on center stage. The bold claims he makes will keep a generation of historians busy running back to the archives to prove, disprove, or amend them. This could bring new attention to Church history and contribute to a renewed appreciation of religion’s formative role in making the modern world. It should also fertilize the study of economic history by giving researchers a reason to further explore the role played by the Church in long-term cultural change.

Now that we know how WEIRD Westerners really are, we might question the utility of using its experience to benchmark policy that is designed to help modernity happen in the rest of the world. What if you are the leader of a country that is not filled with culturally WEIRD people? How do you modernize? The book also leaves open the question of what happens when you have met one of the criteria of modernization and are only partially WEIRD — China and East Asia’s high-performing economies, for example, succeed on education and industrialization, but fall short on democracy. What kind of world order and governance of international relations will be possible when kinship intensity causes such significant variation in the performance of institutions?

There is one clear conclusion: the study of social networks will be essential if we are to understand and motivate long-term cultural change.


Goody, Jack. 1983. The Development of the Family and Marriage in Europe. Cambridge: Cambridge University Press.

Mitterauer, Michael. 1991. “Christianity and Endogamy.” Continuity and Change 6 (3): 295–333.

Reynolds, Philip L. 2016. How Marriage Became One of the Sacraments: The Sacramental Theology of Marriage from Its Medieval Origins to the Council of Trent. Cambridge: Cambridge University Press.

Root, Hilton L. 2020. Network Origins of the Global Economy: East vs. West in a Complex System’s Perspective. Cambridge: Cambridge University Press.

Schulz, Jonathan F. 2020. “Kin-Networks and Institutional Development.” Working Paper. SSRN.

Ubl, Karl. 2008. Inzestverbot Und Gesetzgebung. Die Konstruktion Eines Verbrechens (300-1100). Berlin: Walter de Gruyter.

Whitelock, Dorothy. 1952. The Beginnings of English Society. Baltimore: Penguin Books.



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Subject(s):Economic Development, Growth, and Aggregate Productivity
Economywide Country Studies and Comparative History
Historical Demography, including Migration
Social and Cultural History, including Race, Ethnicity and Gender
Geographic Area(s):Europe
Time Period(s):Ancient
16th Century
17th Century
18th Century
19th Century
20th Century: Pre WWII
20th Century: WWII and post-WWII