What did Heinrich et al's behavioural experiments in 15 small scale societies find about the canonical assumption that individuals are entirely self interested?
Mean offers in industrial societies were close to 44%, the offers in their sample ranged from 26%-58%. While modal offers are consistently 50% in industrialized societies, their samples varied 15-50%. In industrialised societies, offers below 20% are rejected with probability 0.4-0.6, rejections of low offers are v. rare in some groups. In other groups, there were substantial rejection rates, including rejections of offers over 50%.