How did inequality arise? The question was famously raised by Jean-Jacques Rousseau. His answer was controversial, to say the least. He did not have much information to base his analysis on, given that the discovery of humanity being a product of Darwinian evolution was yet to be made. Although there was some information about how hunter-gatherers lived in parts of the world that were being colonized by European traders and settlers, it was fragmentary at best. The book "The Creation of Inequality" by Kent Flannery and Joyce Marcus does the hard work of summarizing the anthropological and archaeological record to identify the stages and processes that transformed human society from the large degree of equality that characterized nomadic hunter-gatherers (ignoring gender inequality) before about 12,000 years ago. It is a monumental effort, and the results give them the basis to provide some more facts-based answers to Rousseau's question.
Flannery and Marcus present short histories of a large number of societies based on their reading of the available evidence. The focus is to identify markers that give information about the level and type of inequality, political and social changes, and the growth and decay of the societies. The examples range from the Pacific archipelagos, the Central American jungles, the plains of Sumer, to the different Indian societies on North America and more. It is a fascinating account of the diversity of human societies, but there are also many recurring patterns. Flannery and Marcus analyze these patterns in terms of changes of the social logic as a result of the interactions between the natural, political, and spiritual environment with the inventions that were needed to solve day-to-day problems. Several different societies went through changes and stages that display many similarities, despite being far separated from each other in time and space, and having no knowledge of each other. Independent processes displaying similarities are good indicators that there must be some underlying common propensities.
A theme that becomes clear is that one important step providing a foundation for inequality was the formation of more or less permanent settlements. These did not have to be based on agriculture; there are examples of hunter-gatherers that lived in environments with sufficient resources for people to get by without having to move around. This allowed the creation and accumulation private property. Another theme is the forming of achievement-based hierarchies: Persons (men, usually) who were successful gained prestige and could become chiefs, while less successful persons became commoners or even slaves. However, the chiefs could not automatically pass on their status to their children. That would require further social inventions.
The account is complex and wide-ranging. Each society or region is dealt with in separate chapters. One important point is the difference between hereditary inequality in its various shapes, and achievement-based inequality. One point they make is that hereditary inequality can be inferred when the graves of children contain items of luxury and symbols of power; since they could not have achieved this themselves, it indicates that their status depends on inheritance. The historical record shows that the move from achievement-based inequality to hereditary inequality is not inevitable. However, the social logic works strongly in this direction given certain environmental conditions. Formation of large-scale states are most often the result of competition between neighboring chiefdoms.
I cannot vouch for the accuracy of their historical accounts. But the general approach seems sensible, and they do point out when they regard the available data to be insufficient for conclusions to be drawn. I do not get the impression that the authors are trying to push an agenda through tendentious reporting. The book is rather long since the authors cover many different societies, and at times it is hard to keep up with the wealth of details. However, it is hard to see how it could have been done differently without losing the concreteness that is the unique point of their approach.
A question is posed in the final chapter: How can our current societies be made more egalitarian? One response is: Put hunter-gatherers in charge. It is a provoking thought. Exactly how this could be achieved is left unspecified. The authors do not discuss our current Western societies in any depth. They are based on meritocracy, rather than aristocracy and monarchy, at least notionally. This means that modern societies have an ideological basis that implies greater political equality than in the preceding historical era. But at the same time material inequality has increased. How do we analyse the social logic that has produced this state of affairs, and how do we want to change it? This book provides much food for thought about these vital issues.