A Brief History of Inequality
Various struggles for equal rights have been a prominent feature of our times. So what does history have to say about the subject?
Our closest primate relatives, the three species of great apes of Africa, are notably hierarchical says Christopher Boehm. He notes also that the last 5000 years of human history have been dominated by societies that are highly hierarchical. But hierarchy is far from the universal rule. The last several hundred years have seen powerful anti-hierarchical movements, originating mainly in Western Europe. Moreover, it seems that before 12,000 years ago, all humans lived in hunter-gatherer bands which, like their contemporary counterparts, were quite egalitarian, at least among adult males.
In short, the history of hierarchy among humans is decidedly mixed. It would easy to dismiss the egalitarian episodes as abberations, but the fact that so much of our history appears egalitarian as well as the strong feelings that so often arise in its favor argue for the opposite. Nonetheless, egalitarian societies require some explanation. Fundamentally that is because they require that weaker individuals impose some sorts of limits on the strong. That is not something that happens naturally in animal societies.
Whether you want to accept evolutionary reasons for our egalitarian behaviors or not, there is an evolutionary logic arguing against egalitarianism. Briefly, it goes like this: suppose that you have two groups each with a dominant individual. In one, the dominant individual grabs much more than his share of the resources and reproductive opportunities while in the other, the subordinate individuals cooperate to deprive the dominant individual of an outsized share. Thus, in the first group, most reproduction is done by the dominant, most fit, individual, whereas in the second group it's more widely dispersed, and less fit individuals do more of the reproduction. Hence fitness is accelerated in group one and depressed in group two, and, over time, group two should be bred out of existence. This leaves the question of how egalitarian behaviors could persist, and in fact become dominant in human societies over a hundred thousand years (or longer). The only obvious answer is that the egalitarian behavior could confer a special group evolutionary advantage by facilitating more cooperation than would be possible in a hierarchy.
Students of evolution will recall that there are potent arguments against group selection. Essentially they reduce to the fact that altruistic behavior, except towards very close kin, seems to reduce fitness. It is a fact, however, that the most successful animal groups are highly social species, the so-called Eusocial species, including ants, bees, and human beings. The ants and bees manage the group selection feat by a peculiar sexual system that severely restricts reproduction and ensures that all members of a colony are extremely closely related. Human's don't do that.
The core problem with group selection notions is that evolution rewards defectors, that is, those who don't altruistically support the group. The hymenoptera avoid this problem by making potential defectors infertile and genetically dependent on the queen. For humans, group selection and altruism require some other kind of rationale to avoid being selected out. That mechanism seems to be punishment of defectors. s.