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Open Access Publications from the University of California


Cliodynamics is a transdisciplinary area of research integrating historical macrosociology, cultural and social evolution, economic history/cliometrics, mathematical modeling of long-term social processes, and the construction and analysis of historical databases. Cliodynamics: The Journal of Quantitative History and Cultural Evolution is an international, peer-reviewed, open-access journal that publishes original articles advancing the state of theoretical knowledge in this transdisciplinary area. In the broadest sense, this theoretical knowledge includes general principles that explain the functioning, dynamics, and evolution of historical societies and specific models, usually formulated as mathematical equations or computer algorithms. Cliodynamics also has empirical content that deals with discovering general historical patterns, determining empirical adequacy of key assumptions made by models, and testing theoretical predictions with data from actual historical societies. A mature, or ‘developed theory’ thus integrates models with data; the main goal of Cliodynamics is to facilitate progress towards such theory in history and cultural evolution.

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Cliodynamics is a member of the Directory of Open Access Journals (DOAJ) and Scopus

Editor's Column

Cultural Evolution and Cliodynamics

The column by the Editor-in-Chief explaining the background of the new journal subtitle


The Silk Roads: a Mathematical Model

This paper concerns the mathematical modeling of historical processes; specifically, the temporal dynamics of the Silk Roads described by formal spatial equations. Historical data indicate that the location of the trade routes known as the Silk Roads varied dramatically from epoch to epoch. These changes arose from a number of causes—population oscillations, economic trends, diseases, and warfare—all of which affected the Silk Roads’ geographical location in different eras, and also determined their rise and demise in each epoch. Mathematical simulation predicting the Silk Roads’ location in each epoch could help to distinguish the most significant determinants of their fluctuations and to estimate where and when these factors were especially prominent. In this paper, we examine the hypothesis considered by Jeremy Bentley (1993), who suggested that one of the most important causes of the Silk Roads’ prosperity was the development of large-scale empires across Eurasia. Empires stimulate the exchange of commodities for the rise of supply-and-demand of bulk and prestige goods, construct roads and related infrastructure that encourage trade, and bring stability to vast areas. The model takes these processes into account and demonstrates that oscillations of the Silk Roads’ activities were induced by the rise and fall of large empires such as the Roman, Parthian, and Mongol empires, as well as the Han and Tang dynasties. Its ultimate demise might have been due to the rise of European maritime shipping, which increased ocean trade at the expense of overland, Eurasian routes.

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The Devoted Actor as Parochial Altruist: Sectarian Morality, Identity Fusion, and Support for Costly Sacrifices

We explore how Darwinian notions of moral virtue and parochial altruism may relate to the emerging cognitive framework of the devoted actor who undertakes extreme actions in defense of group values. After a brief discussion of the theoretical framework, we present exploratory data resulting from interviews of 62 Lebanese individuals of varying religious backgrounds (Sunni, Shia and Christian) in Beirut and Byblos (Jbeil) in a time of heightened tension owing to spillover from the Syrian civil war. Analytic measures focused on willingness to make costly sacrifices for confessional (religious) groups and sectarian values, as a function of the degree to which people perceived universal and parochial values to be morally important, and considered their personal selves “fused” with their group. Sectarian moralists who fused with their religion expressed strong willingness to support costly sacrifices for the group, whereas people who fused with their religion but moralized universal values over sectarian ones were least likely to support costly sacrifices. In addition, when people believed that they had control over their future, fusion increased support for costly sacrifice and desired social distance to outgroups. These results have implications for notions of religion as both a booster and buffer to costly sacrifices, and the impact of identity fusion for and against extreme actions.


For Cause and Comrade: Devoted Actors and Willingness to Fight

This report provides initial evidence that “devoted actors” who are unconditionally committed to a sacred cause, as well as to their comrades, willingly make costly sacrifices, including fighting and dying. Although American military analysts since WWII tend to attribute fighting spirit to leadership and the bond of comradeship in combat as a manifestation of rational self-interest, evidence also suggests that sacrifice for a cause in ways independent, or all out of proportion, from the reasonable likelihood of success may be critical. Here, we show the first empirical evidence that sacred values (as when land or law becomes holy or hallowed) and identity fusion (when personal and group identities collapse into a unique identity to generate a collective sense of invincibility and special destiny) can interact to produce willingness to make costly sacrifices for a primary reference group: by looking at the relative strength of the sacred values of Sharia versus Democracy among potential foreign fighter volunteers from Morocco. Devotion to a sacred cause, in conjunction with unconditional commitment to comrades, may be what allows low-power groups to endure and often prevail against materially stronger foes.


The SESHAT Databank Project: the 2014 Report

This article contains a report on research activities taking place under the SESHAT Database Project during 2014.

Book Reviews

A ‘Perfect Storm’ in the Collapse of Bronze Age Civilization? Useful Insights and Roads not Taken

A Review Essay on 1177 B.C.: The Year Civilization Collapsed by Eric H. Cline (Princeton University Press)

Developing Scales of Development

A review essay on The Measure of Civilization by Ian Morris (Princeton University Press)

Social Evolution Forum

Blueprint for the Global Village

The Social Evolution Forum on social cooperation in Norway and other Nordic countries (with comment)