by PHILIP GUELPA
A newly published study (“Economic inequality is fueled by population scale, land-limited production, and settlement hierarchies across the archaeological record,” PNAS, April 14, 2025) provides insight into the initial rise of class societies across the world. Using data from 1,100 archaeological sites from Europe, Asia and the Americas, the researchers trace the beginnings of wealth inequality back to over 10,000 years ago, millennia before the first major civilizations (e.g., Egypt, Mesopotamia, the Maya). The study elucidates some of the primary factors in the transition from egalitarian hunter-gatherer social groups to early farming societies in which indications of wealth and status differentiation can be discerned.
The initial processes that eventually led to the emergence of class societies (although the word “class” does not appear anywhere in the PNAS article) began to appear during the last stages of the Pleistocene and the beginning of the Holocene (the post-glacial period in which we have lived for approximately the last 10,000 years). Since there are no written records from those times, the researchers employ a proxy data set—dwelling sizes—specifically the in-ground footprint of structures which are the usual housing remnants, if any, found in archaeological sites. No standing buildings survive from the time period in question. The study gathered data from over 47,000 residential structure remains, documented at 1,100 archaeological sites from around the world. The large sample size alone gives a degree of confidence in the study’s results.
The study identifies several commonalities in the initial emergence of economic inequality:
Growth of wealth differences among households has been a long-term though not universal trend in the Holocene. Marked increases typically lagged plant domestication by 1,000 y[ears] or more and were tightly linked to development of hierarchies of settlement size and land-limited production. We infer that the social upscaling (growth of polities in population and area) that typically began one to two millennia after agriculture became locally common, and continued in some areas throughout the Holocene, interfered with traditional leveling mechanisms including enforcement of egalitarian norms.
In general, in egalitarian societies the dwelling sizes of constituent family groups tend to be similar at any given settlement, reflecting a general equality in economic and social status. As wealth and social stratification developed, the study found that differences in dwelling sizes begin to appear. As societies become more complex, the number of levels of dwelling sizes increases, reflecting the different levels of social stratification.
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