"The earliest humans, hunter-gatherers, were often remarkably egalitarian. But our history as a species did not begin with this “Eden” (we will see how we need to qualify that analogy in a minute), but with primate ancestors who were anything but egalitarian: our nearest primate relatives, the chimpanzees, live in strongly hierarchal bands dominated by alpha males who attempt to maintain sole sexual access to the females of the group and keep both other males and females in subservience to them.
What accounts for the difference between primate bands and hunter-gatherer egalitarians? The absence of a disposition for dominance? Not likely. In Hierarchy in the Forest: The Evolution of Egalitarian Behavior, anthropologist Christopher Boehm argues that we share with chimpanzees and bonobos a tendency toward despotism. Yet nomadic hunter-gatherers have nevertheless been uniformly egalitarian, seemingly for thousands if not millions of years. Boehm explains this seeming contradiction with the claim that hunter-gatherers have “reverse dominance hierarchies”: the adult males in the society form a general coalition to prevent any one of their number, alone or with a few allies, from dominating the others. Male egalitarianism is not necessarily extended to females—the degree to which females are subject to male despotism varies, even among hunter-gatherers. But the reverse dominance hierarchy prevents the monopolization of females by dominant males. This makes possible the heterosexual nuclear family as we know it, based on (relatively) stable cross-gender pair bonding and mutual nurturance of children by parents, precisely what is missing in our closest primate relatives.
Egalitarianism is thus itself a form of dominance, the dominance of what Rousseau would have called the general will over the will of each. The hunter-gatherer band is not, then, the family enlarged; rather it is the precondition for the family as we know it.
Boehm identifies “moral community” and “the deliberate use of social sanctioning to enforce political equality among fully adult males” as the two components of egalitarian social control. I would add ritual as the common expression of the moral community without which the process of sanctioning would make no sense." (http://www.tikkun.org/nextgen/religion-and-equality-in-human-evolution)