Egalitarian revolution in the Pleistocene?

Gavrilets and colleagues argue that such an "egalitarian revolution" could also follow a change in the mating system that would increase father-son social bonds or an increase in fidelity of cultural inheritance of social networks. Interestingly, the fact that mother-daughter social bonds are often very strong in apes suggests (everything else being the same) that females could more easily achieve egalitarian societies.

The model also highlights the importance of the presence of outsiders (or "scapegoats") for stability of small alliances. The researchers suggest that the establishment of a stable group-wide egalitarian alliance should create conditions promoting the origin of conscience, moralistic aggression, altruism, and other cultural norms favoring group interests over those of individuals. Increasing within-group cohesion should also promote the group efficiency in between-group conflicts and intensify cultural group selection.

"Our language probably emerged to simplify the formation and improve the efficiency of coalitions and alliances," says Gavrilets. The scientists caution that one should be careful in applying their model to contemporary humans (whether members of modern societies or hunter-gathers). In contemporary humans, an individual's decision to join coalitions is strongly affected by his/her estimates of costs, benefits, and risks associated as well as by cultural beliefs and traditions. These are the factors explicitly left outside of the modeling framework.

In humans, a secondary transition from egalitarian societies to hierarchical states took place as the first civilizations were emerging. How can it be understood in terms of the model discussed? One can speculate that technological and cultural advances made the coalition size much less important in controlling the outcome of a conflict than the individuals' ability to directly control and use resources (e.g. weapons, information, food) that strongly influence the outcomes of conflicts.

Citation: Gavrilets S, Duenez-Guzman EA, Vose MD (2008) Dynamics of Alliance Formation and the Egalitarian Revolution. PLoS ONE 3(10): e3293. doi:10.1371/journal.pone.0003293

PLEASE ADD THE LINK TO THE PUBLISHED ARTICLE IN ONLINE VERSIONS OF YOUR REPORT: http://dx.plos.org/10.1371/journal.pone.0003293