Hunter-gatherer societies depended on egalitarian and cooperative strategies. The absence of storable wealth, its earliest form coming as food, meant that any excess had to be stored in the bodies of the group or abandoned, and could only be produced in the first place by cooperative actions. If we are in any way adapted to use social strategies, this is the longest acting and most persistent selective force that has driven that adaptation…the economic plenty that gave rise to stratified societies is a relatively modern condition in comparison.