Cultural macroevolution

What has driven the remarkable rises in social scale and complexity since the end of the last Ice Age? What role do religion, warfare, technology and agriculture play in the evolution of states and empires? Our work on cultural macroevolution combines computational modelling with data in order to disentangle the drivers of change in human history.

Drivers of social complexity

Seshat is more than a repository of data. It is structured in such a way that we can test rival hypotheses about what drove the rise of complex states. In a series of articles focusing on agriculture (Currie et al. 2015), military technology (Turchin et al. 2021) and religion (Turchin et al. 2022a; Whitehouse et al. 2022), we have done just that, pitting theory against data to discern which factors have been most important in this process. In 2022 we published our most complete analysis yet of the evolutionary patterns revealed by the data collected in Seshat. “Disentangling the evolutionary drivers of social complexity: A comprehensive test of hypotheses” (Turchin et al. 2022b) appeared in Science Advances. It marshalled data on 17 potential drivers of sociopolitical complexity. Our conclusion? The best-supported model indicated a strong causal role for a combination of increasing agricultural productivity and the adoption of new military technologies – especially iron weapons and cavalry.

Currie, Thomas E., Amy Bogaard, Rudolf Cesaretti, Neil Edwards, Pieter Francois, Phillip Holden, Daniel Hoyer, et al. 2015. ‘Agricultural Productivity in Past Societies: Toward an Empirically Informed Model for Testing Cultural Evolutionary Hypotheses’. Cliodynamics 6 (1). https://doi.org/10.21237/C7clio6127473.

Turchin, Peter, Daniel Hoyer, Andrey Korotayev, Nikolay Kradin, Sergey Nefedov, Gary Feinman, Jill Levine, et al. 2021. ‘Rise of the War Machines: Charting the Evolution of Military Technologies from the Neolithic to the Industrial Revolution’. PLOS ONE 16 (10): e0258161. https://doi.org/10.1371/journal.pone.0258161.

Turchin, Peter, Harvey Whitehouse, Sergey Gavrilets, Daniel Hoyer, Pieter François, James S. Bennett, Kevin C. Feeney, et al. 2022. ‘Disentangling the Evolutionary Drivers of Social Complexity: A Comprehensive Test of Hypotheses’. Science Advances 8 (25): eabn3517. https://doi.org/10.1126/sciadv.abn3517.

Turchin, Peter, Harvey Whitehouse, Jennifer Larson, Enrico Cioni, Jenny Reddish, Daniel Hoyer, Patrick E. Savage, et al. 2023. ‘Explaining the Rise of Moralizing Religions: A Test of Competing Hypotheses Using the Seshat Databank’. Religion, Brain & Behavior 13 (2): 167–94. https://doi.org/10.1080/2153599X.2022.2065345.

Whitehouse, Harvey, Pieter François, Patrick E. Savage, Daniel Hoyer, Kevin C. Feeney, Enrico Cioni, Rosalind Purcell, et al. 2023. ‘Testing the Big Gods Hypothesis with Global Historical Data: A Review and “Retake”’. Religion, Brain & Behavior 13 (2): 124–66. https://doi.org/10.1080/2153599X.2022.2074085.

Moralizing religion

Today, the world’s religious landscape is dominated by traditions like Christianity, Islam, Buddhism and Hinduism. These are moralizing religions: they postulate supernatural agents or forces that systematically reward virtuous behaviour and punish transgressions across a broad range of human affairs, ranging for example from sexual conduct to repaying debts and from respect for property to acts of charity. In deep historical perspective, they are relative latecomers, gaining in popularity after the turbulent warring polities and empires of the last millennium BCE. By contrast, we have evidence for communal ritual and the building of sacred monuments dating back to the end of the last Ice Age, many millennia before.

How and why have moralizing religions spread to all corners of the globe? What is the relationship between the rise of these traditions and the growth of social scale and complexity? These questions have been the focus of intense debate. However, progress has been limited by the availability of quantitative data to test competing theories, by divergent ideas regarding both predictor and outcomes variables, and by differences of opinion over methodology.

To address all these problems, we use quantitative analysis and the massive accumulation of historical data collected in the Seshat: Global History Databank. In addition to the Big Gods hypothesis, which proposes that moralizing religion contributed to the success of increasingly large-scale complex societies, we considered the role of warfare, animal husbandry, and agricultural productivity in the rise of moralizing religions.

Our analyses suggest that such beliefs did not drive the rise of social complexity. Rather, intergroup warfare, supported by resource availability, played a major role in the evolution of both social complexity and moralizing religions. The correlation between social complexity and moralizing religion seems to result from shared evolutionary drivers, rather than from direct causal relationships between these two variables.

To dig more deeply into the rise of moralizing religions in a nuanced, qualitative way, we are also working on a multi-author volume,the Seshat History of Moralizing Religion (edited by Jennifer Larson, Jenny Reddish and Peter Turchin). Incorporating perspectives from archaeologists, anthropologists, historians of religion and scholars of cultural evolution, the volume highlights specific regional trajectories while drawing out common patterns in the emergence and spread of beliefs about supernatural punishment and reward.

Larson, Jennifer, Jenny Reddish, and Peter Turchin, eds. Forthcoming. The Seshat History of Moralizing Religion. Chaplin, CT: Beresta Books.

Turchin, Peter, Harvey Whitehouse, Sergey Gavrilets, Daniel Hoyer, Pieter François, James S. Bennett, Kevin C. Feeney, et al. 2022. ‘Disentangling the Evolutionary Drivers of Social Complexity: A Comprehensive Test of Hypotheses’. Science Advances 8 (25): eabn3517. https://doi.org/10.1126/sciadv.abn3517.

Turchin, Peter, Harvey Whitehouse, Jennifer Larson, Enrico Cioni, Jenny Reddish, Daniel Hoyer, Patrick E. Savage, et al. 2023. ‘Explaining the Rise of Moralizing Religions: A Test of Competing Hypotheses Using the Seshat Databank’. Religion, Brain & Behavior 13 (2): 167–94. https://doi.org/10.1080/2153599X.2022.2065345.

Whitehouse, Harvey, Pieter François, Patrick E. Savage, Daniel Hoyer, Kevin C. Feeney, Enrico Cioni, Rosalind Purcell, et al. 2023. ‘Testing the Big Gods Hypothesis with Global Historical Data: A Review and “Retake”’. Religion, Brain & Behavior 13 (2): 124–66. https://doi.org/10.1080/2153599X.2022.2074085.

Human sacrifice

From the point of view of modern society, human sacrifice is a bizarre and gruesome ritual which defies scientific explanation. Yet the ritualized killing of humans to gain supernatural benefits was practiced by past societies on all inhabited continents. It is often associated with funerals (e.g. to provide the elite dead with servants or companions in the next life), the completion of major constructions (e.g. bridges and monuments), or it may be done in response to natural disasters or the threat of conquest (“emergency human sacrifice”). Human sacrifice has arisen at multiple times and places around the globe seemingly independently, but it shows a general temporal pattern. In the earliest known periods it tends to be rare or absent. At some point it increases in frequency and scale. And then it goes away—sometimes gradually, and sometimes abruptly. Today, no society practices human sacrifice as a collective ritual.

Scholars have put forward several hypotheses to account for the rise and fall of human sacrifice and its relationship to cultural evolution. The social control hypothesis proposes that it bolsters the power of elites by lending them sacred authority and motivating compliance via intimidation. The elevator-of-reason hypothesis focuses on the decline of the practice, suggesting that as intellectual sophistication increases, societies tend to abandon ritual killing along with other “superstitious” cultural practices.

In order to evaluate rival theories, we are applying quantitative analysis to the vast accumulation of time-resolved data in Seshat: The Global History Databank. We combined data on social scale and inequality, warfare, information systems and other variables with available information on human sacrifice across 33 world regions from the Neolithic period to 1800 CE. These data reveal that this ritual is rare in small-scale, acephalous societies. Then, as hereditary elites emerge and polity populations reach the tens of thousands, there is a peak of human sacrifice incidence. In more complex states, with populations in the hundreds of thousands, its frequency starts to decline. Our analysis shows that this pattern is not a side effect of societies becoming more “rational.” Rather, increasing military competition (especially after the emergence of mounted warfare in Eurasia) exerts strong pressure on societies to abandon human sacrifice. These results are consistent with the idea that extreme inequality, exemplified by practices such as HS, undermines the capacity of large-scale complex human societies to survive in competition with other polities.

Alongside this quantitative work, we are also working on an edited volume, the Seshat History of Human Sacrifice. The goal of the book is to provide contextualized data about the practice of human sacrifice in past societies, to survey the diversity of proximate reasons (where known) and the actors involved in this ritual. A central question that the book asks is not only why human sacrifice was practiced in a particular society, but what were the possible evolutionary drivers and circumstances of the appearance and then abandonment of HS in various societies. The intended use of the book is as a reference that can be mined for cross-cultural insights on this ritual.

Evolution of trade

Thousands of years ago, most humans lived in small-scale societies, interacting with few other communities at most a few hundred kilometers away. Today, we live in large states with populations of hundreds of millions, exchanging goods and information globally with often anonymous individuals that we may never interact with more than once. What drove this enormous expansion of trade networks and their periodic contractions? What have been the consequences for economic and social development and interstate conflict? How have negative side-effects been mitigated in the past, and how can we manage the continuing expansion of global exchange in the future?

We have formed a multidisciplinary research group to explore these critical questions, led by Prof. Helena Miton of the Stanford Business School. Our goal is to curate a unique, large-scale historical dataset on exchange networks and the institutions and cultural practices that support them. This exciting work will create the first dataset of its type. Moreover, while the literature has recorded case studies and advanced a few hypotheses (e.g., on the role of contracts, or specific institutions like record-keeping or money), it lacks systematic evaluation of drivers and consequences of changes in exchange networks. Utilizing methods developed by the Seshat Databank, our novel dataset will allow us for the first time to systematically test hypotheses on the policies and institutions supporting trade expansion or leading to its contraction – and their impact on social functioning. Our project will create a major new resource for the study of cultural evolution and the evolution of exchange networks, and will answer key questions about our shared past and our potential future.

  1. Home
  2. /
  3. Research
  4. /
  5. Current Research Projects
  6. /
  7. Cultural macroevolution

© Peter Turchin 2023 All rights reserved

Privacy Policy