> I think humans may have a genetic predisposition to equality. What made me realize this was going to Africa and seeing lots of animals in the wild. All or nearly all the big mammals lived in groups and cooperated to survive. It was clear that our ancestors would in their day have been one of these groups, also cooperating to survive (as hunter-gatherers still do in a few places), and that their cooperative inclinations were probably genetically preprogrammed.
I'm not sure living in groups and cooperating implies a genetic predisposition to equality. Even though a group might have, say, twenty to fifty members, some members tend to rule and others tend to hang on the outskirts. I'd pick Venkat Rao's division into Sociopaths, Clueless, and Losers (http://www.ribbonfarm.com/2009/10/07/the-gervais-principle-o...) as the best way to divide up types of people in such a group. He writes about their role in businesses, but it's the same in a small societal group. The Sociopaths are the jocks who absolutely must have the power, eat the most food, and have the most offspring. The Losers are the ones who live at the edge of the group, eat the least food, and be eaten first by predators. The Clueless are the majority who follow the Sociopaths' rules and rise slowly through the group hierarchy to their natural level of competence.
Perhaps society is best modeled as a cell, where the Sociopaths are the nucleus and the Losers are the membrane. It does seem to be a male-oriented model, where females act more like glue, facilitating relationships. The male Sociopaths would have two or more females each, eat the food, feed the women, and produce the most offspring. The male Clueless would only have one female and follow whatever other rules the Sociopaths impose, and get food based on their rank in society. Perhaps the females overall are most similar to male Clueless in this model.
The male Losers would be the first to miss out on the food, not get any girls, and die young, being the first to be sacrificed to predators. And maybe there's the reason why Sociopaths naturally shun any interaction with Losers, going through the Clueless intermediaries, as in "the jocks hate the nerds". When there's any threat to their survival or status, the Sociopaths in the nucleus can't afford to have any emotional attachment to the Losers in the outer membrane. They need to be able to sacrifice Losers without hesitating if that's required for their own survival.
I guess I'm saying not only are mammals built out of biological cells internally, but also make up societal cells externally. When there's plenty of food and the group grows too big, the Sociopaths start electioneering among the Clueless for loyalty. The group will eventually split in half, just like cells do, some Sociopaths taking some of the Clueless with them and the others taking the other Clueless. When there's just enough food for the Sociopaths to multiply but not enough Clueless for a successful cell split, the Sociopaths will turn on one another, a coup takes place, and the losing Sociopaths killed or thrown outside the membrane.
This model describes how a genetic predisposition to inequality and hierarchy can also explain group living and apparent cooperation.