Oxen and horses may have been origin of wealth inequality

Study of societies spanning 11,000 years suggests plow animals facilitated widening wealth gap.  

Amid reports that the richest one percent now own around 50 percent of the world’s household wealth, emerging archaeological research drives home just how historically unusual that level of inequality is. The researchers compared house sizes within 63 societies across Europe, Asia, and North America—as well as two in Africa. The analysis covered a range of society types over roughly the last 11,000 years, from hunter-gatherer settlements to ancient cities. As expected, they found that wealth inequality within these societies increased over time, but typically didn’t come close to levels seen today in places like the US and China. More surprisingly, the historical data also revealed that wealth inequality increased far more in Eurasia than it did in the New World. We asked study author Tim Kohler about the discrepancy.

ResearchGate: How did you determine levels of inequality in the societies you studied?

Tim Kohler: Although anthropologists and economists have some basic expectations about how wealth distributions should change as societies develop agriculture and state-level organizations, we wanted to look at what the archaeological record actually says.

We needed to develop a single consistent proxy for wealth that would be applicable to all types of societies. We used house sizes, specifically the distribution of house sizes, to calculate Gini coefficients for the societies in our sample. Gini coefficients range from near zero, when all households have equal wealth, to near one, when one household controls nearly all the wealth.

RG: What did you find?

Kohler: We found that generally speaking, wealth differences did increase as people domesticated plants and animals, and as they developed larger societies with more hierarchical patterns of control. All this was as expected. What we did not expect was that within two to three thousand years after developing agriculture, wealth differentiation trajectories began to diverge. The Old World societies in our sample developed greater wealth differentiation than was ever common among the New World societies we studied.


“Maintaining teams of draft animals like oxen required some wealth.”


RG: Why do you think there was more wealth inequality in the Old World than in the New World?

Kohler: We hypothesize that the original source of the difference was that people in Eurasia had access to large domesticable mammals that could be used for ploughing, thus allowing people to farm more areas farther from their settlements more efficiently. This is called agricultural extensification. Households that could do this were apparently able to increase their incomes relative to households that couldn’t. But maintaining teams of draft animals like oxen required some wealth, so these opportunities were not equally distributed. In fact, this seems to have been a good way to tie wealth to income, which is important for increasing wealth differentiation.

But such agricultural extensification is “land hungry” and tends to first deny poorer households access to the best and most local lands and eventually creates a class of landless peasants. Prior to the arrival of Columbus, landless peasants were never prominent in the New World, since without draft animals, agricultural extensification was much more limited. None of the New World domesticates, which include llamas, alpacas, dogs, and turkey, were suitable for ploughing. Where it occurred, it probably did not increase per capita productively markedly.

Eventually of course, during the Bronze Age, animals such as horses and camels helped create a mounted warrior elite that could expand the scope of polities enormously. Both the presence of these elites, and the existence of the larger polities they created, helped increase unevenness of wealth distributions.


“Most societies in the past had much more equal divisions of wealth.”


RG: Do your findings tell us anything about inequality today?

Kohler: Work like this helps put contemporary wealth disparities into a long-term context. People tend to assume that the conditions they grew up in are universal, but that is rarely true. Work like this shows that most societies in the past had much more equal divisions of wealth than is the case in societies like the United States, or even China, today. Our results show that some wealth disparities are universal. Very high wealth disparities in countries like the USA today are historically uncommon.

RG: What’s next for this research?

Kohler: This is just a pilot study, and we need to measure wealth concentrations in many more societies and in parts of the world that were not included in the present sample, like South America and South Asia. Comparison of wealth-differentiation trajectories from more areas will help isolate the causes.

Contemporary studies suggest that high wealth disparities can lead to a number of social ills, including lack of upwards mobility, inefficient and coercive institutions, lower rates of growth, and perhaps political instability. Can we find evidence for any of these relationships in prehistory? Can we begin to identify Goldilocks levels of inequality that are neither too high, nor so low that they engender mediocrity or lack of innovation? We hope that this work helps open up such questions for archaeology.