Cliodynamics

Rising economic inequality in the United States has become a topic of political interest in recent years. Inequality appears to show cycles corresponding to secular cycles, suggesting the possibility of declining inequality in the future. The most recent episode of declining inequality in America is known as the Great Compression. It occurred in the middle of the 20^th century. This paper uses the guided variation cultural evolution model (Boyd and Richerson 1985:95-7) to explain shifting trends in inequality in five nations. According to this analysis, the Great Compression was largely due to a shift in the business environment reflecting tax and other economic policy implemented over the 1914-45 era. The cultural evolutionary response to this environmental change was to replace “shareholder primacy” cultural variants with “stakeholder capitalism” variants which resulted in lower inequality. Half a century later, new policy, implemented in response to the great inflation following the collapse of the Bretton Woods system, changed the business environment again in ways that favored shareholder primacy cultural variants and rising inequality. The extent to which this occurred depended on the degree to which stakeholder capitalism was integrated into institutions.

Despite recent and past research into the collapse of ancient states and into ancient inequality, the possible role of inequality in collapse has been ignored. Inequality as a potential explanatory factor in civil war and collapse in modern states has been the subject of around 150 flawed regression analyses, from which no consensus has emerged. Data for ancient states is insufficient to enable such quantitative modelling. But case studies of the Egyptian Old Kingdom, the Western Roman Empire and the Classic Maya suggest some role for inequality, although the data is sparse and contentious. Paucity of data probably reflects lack of interest and a recent study (Kohler and Ellyson 2018) shows what can be achieved.

The historical turn in the social sciences has been neglected by historians. This has caused social scientists to use much data which has not been curated by experts focused on the relevant time periods and geographic locations. A recent article by Oka et al. investigating the important question of historical trends in violence is a good example. A detailed survey of Oka et al.’s Persian, Greek and Roman population, army size and casualty data reveals several problems. The uncertainty in ancient data, especially casualty figures, has been underappreciated by Oka et al. In population and army size data, some speculative and dependent data points have been treated as independent. There are also inconsistencies in the data and some inflated figures. The situation is worse for the ancient army size and casualty figures for individual battles used by Oka et al., which suffer from systematic biases designed to magnify the achievements of the historian's own culture. This is clearly illustrated by the main battles of Alexander the Great against the Persians, in which Alexander's forces, although greatly outnumbered, are supposed to have inflicted hundreds or thousands of times more casualties that they sustained. These issues demonstrate the importance of curation of such data by scholars focused on the relevant time periods and cultures, and we recommend that historians become actively involved in such research.

A Review of The First Farmers of Europe: An Evolutionary Perspective by Stephen Shennan (Cambridge University Press, 2018)