Benoit Dubreuil’s Human Evolution and the Origins of Hierarchies seeks to explain two historical transitions in social hierarchies in human (and pre-human) history. The first is the transition from dominance hierarchies, such as those lived in by our common ancestor with the chimpanzee, to egalitarian social relationships. The second is from those egalitarian relationships to the large-scale, state-based hierarchies we see today.
The assumption as to the existence of the first transition is largely taken from the work of Christopher Boehm (Hierarchy in the Forest: The Evolution of Egalitarian Behavior). I have not read Boehm’s work yet, so I will leave this assumption alone apart from noting that when talking about the end of dominance hierarchies, this is not to suggest that there are no hierarchies. Rather, they are based on cooperation, coalitions and other socially based arrangements, as opposed to raw strength and aggression. As noted in the work of Napoleon Chagnon, egalitarian societies can have very unequal distributions in areas such as access to mates.
Dubreuil’s argument is that each transition was driven by the evolution of the human mind. Dominance hierarchies were destabilised as early humans gained the ability to cooperate and coordinate to bring down dominant individuals. The re-emergence of hierarchies, although different in form, was driven by the cognitive changes associated with the behavioural modernisation of humans. The institutions necessary for efficient enforcement of norms in a large-scale society require cognitive abilities that humans did not have at the time of their earlier egalitarian societies.
On one level, the argument behind the second transition must be right. The common ancestors of humans and chimpanzees, and many earlier humans, simply did not have the cognitive firepower to create the institutions underlying a modern state. The more particular claim of Dubreuil that the emergence of state-based hierarchies are directly linked to these cognitive changes faces some challenges due to the gap in time between the emergence of behaviourally modern humans (as identified by evidence such as from the fossil record) and the establishment of agriculture and its associated large-scale societies. One potential reconciliation is that humans continued to evolve beyond the time when he (and most anthropologists) would consider them to be behaviourally modern. As I would claim, humans have continued to evolve through to today.
Dubreuil’s thesis does create an interesting challenge for those that claim that human nature supports egalitarian social structures. If the departure from those structures was driven by the evolution of the mind, has human nature changed such that these egalitarian relationships are no longer stable or feasible? It may be possible to argue that an egalitarian society is the preferred social arrangement, but the argument must be more sophisticated than simply claiming that egalitarian structures were the predominant evolutionary environment faced by early humans.
Dubreuil’s book started life as a thesis, and to some extent, it still feels like one. The first two chapters, in which Dubreuil establishes the foundations of norm enforcement in humans, form an excellent literature review on experiments about cooperation, fairness, punishment and envy. It is worth grabbing the book for these alone. In the other three chapters, Dubreuil crafts the argument. Dubreuil convinced me of the general idea, but with issues such as the timing of the transition to modern behavior, there is some way to go before the finer points of his argument will be convincing.