Across the past 10,000 years, human societies changed from small-scale, relatively egalitarian groups into large, differentiated societies with extensive divisions of labor, unequal distributions of wealth and power, and elaborate systems of governance. This transformation was neither smooth nor irreversible.
Research Topics
Main Questions
Three problems guide the research program
The first problem is the long-run growth in the scale and organizational complexity of human societies during the past 10,000 years. The second is the recurrent fragility of complex states: why periods of social stress can lead to fragmentation, institutional breakdown, and collapse.
The third problem is comparative resilience. Why do some societies pass through major crises with limited damage while others experience extensive violence, population decline, and the loss of institutions or accumulated knowledge?
Historical Pattern
Social complexity advances unevenly
The long-run growth of social complexity has repeatedly been interrupted by turbulence and dysfunction. Political fragmentation, economic simplification, demographic decline, and institutional loss appear in the histories of many large-scale societies, including modern ones.
Scholars have proposed many explanations for both the rise of complex societies and their breakdown.
Research Approach
Theory tested against comparative historical evidence
At the Complexity Science Hub, the research program combines computational and statistical methods with cultural evolution, historical social science, archaeology, and formal models of collective behavior.
A central empirical resource is Seshat: Global History Databank, co-founded in 2011 by Peter Turchin, Harvey Whitehouse, and Pieter François. Its comparative record makes it possible to evaluate theories of social complexity, resilience, and breakdown across regions and long periods of time.
CSH Projects
Projects and collaborations at the Complexity Science Hub
The CSH research topic Social Complexity & Collapse connects this long-term program to focused projects. The entries below link to the institutional project records; dates distinguish the active program from completed collaborations.
- AReS: Assessing societal resilience (2026–2028)
- An FWF-funded project led by Peter Turchin that compares historical and modern societies to identify the conditions supporting adaptation, collective action, and resilience under severe shocks.
- Cities and Warfare (ongoing)
- A collaboration between the Complexity Science Hub and the University of Hong Kong studying how geography and warfare shaped the rise of cities and complex societies. Building on research into early China, the project is collecting comparative archaeological and historical data for Mesopotamia, Egypt, and other regions.
- Human Population Cycles (2024)
- A collaboration with Epigenes Australia using comparative evidence on population change, warfare, famine, and epidemics to investigate recurring demographic cycles.
- HuBERT and historical data (2023)
- An earlier natural-language-processing project exploring how historical and archaeological literature can be screened and translated into structured, interoperable historical datasets.
