Egalitarianism. An evolutionary perspective

Two parties bargaining over a pie, the size of which is determined by their previous investment decisions. Investment costs are heterogeneous. The bargaining rule is sensitive to investment behavior. Two games are studied which differ for the considered sociopolitical structure: communal property in one case and private property in the other. We hereby show that in both games when a unique stochastically stable outcome exists a norm of investment and a norm of surplus division must coevolve. While the investment norm always supports the efficient investment profile, the surplus division norm may differ among these games depending on the size of investment cost gap. Under private property only the egalitarian surplus division evolves. Under communal property instead two different surplus division norms may evolve: the egalitarian one and an inegalitarian norm. We show that no cap to payoffs inequality emerges under private property while an inequality payoff cap endogenously evolves under communal property. The games have been proposed to explain the social norms used in modern hunter-gatherer societies.