Identifying key socioecological factors influencing the expression of egalitarianism and inequality among foragers

Abstract

Understanding how resource characteristics influence variability in social and material inequality among foraging populations is a prominent area of research. However, obtaining cross-comparative data from which to evaluate theoretically informed resource characteristic factors has proved difficult, particularly for investigating interactions of characteristics. Therefore, we develop an agent-based model to evaluate how five key characteristics of primary resources (predictability, heterogeneity, abundance, economy of scale and monopolizability) structure pay-offs and explore how they interact to favour both egalitarianism and inequality. Using iterated simulations from 243 unique combinations of resource characteristics analysed with an ensemble machine-learning approach, we find the predictability and heterogeneity of key resources have the greatest influence on selection for egalitarian and nonegalitarian outcomes. These results help explain the prevalence of egalitarianism among foraging populations, as many groups probably relied on resources that were both relatively less predictable and more homogeneously distributed. The results also help explain rare forager inequality, as comparison with ethnographic and archaeological examples suggests the instances of inequality track strongly with reliance on resources that were predictable and heterogeneously distributed. Future work quantifying comparable measures of these two variables, in particular, may be able to identify additional instances of forager inequality. This article is part of the theme issue ‘Evolutionary ecology of inequality’.

Toward an evolutionary ecology of (in)equality

“…Within the evolutionary ecology paradigm, perhaps the most frequently invoked drivers are ecological parameters such as resource density, predictability, and patchiness or clumping that facilitates control by a subset of individuals within a society [8,9]. In this issue, theoretical and cross-cultural analyses highlight the effect of these variables in shaping the form and degree of inequality [10][11][12]. Their importance is given further support in archaeological case studies, which also implicate Malthusian population dynamics involving competition for diminishing resources [13,14].…”

“…The near absence of institutionalized differences in wealth and power for most of the history of our species raises the question of what changed. Several papers in this special issue offer important clues [10,14,18]. The development and spread of agriculture certainly accounts for some of the temporal dynamics of institutionalized inequality, but its absence in low-intensity 'horticultural' societies [65], muted presence even among some agriculturally dependent state-level societies [66][67][68] and multiple cases of non-egalitarian hunter-gatherers [69,70] indicate it cannot be the only, or perhaps even the main, explanation.…”

“…In terms of timing, the high-amplitude high-frequency climate fluctuations of the Pleistocene, and their amelioration in the Holocene, suggests a historically contingent answer for the late emergence of inequality [ 9 , 71 ]. In particular, Holocene climate amelioration increases the economic defensibility of high-quality resource patches by dominants, who can transmit these holdings to descendants as well as offer access to subordinates in exchange for labour and other services [ 9 , 10 ].…”