Understanding the egalitarian revolution in human social evolution.

Humans are unique among animals in cooperating in large groups of unrelated individuals, with a high degree of resource sharing. These features challenge traditional evolutionary theories built on kin selection or reciprocity. A recent theoretical model by Gavrilets and colleagues takes a fresh look at the 'egalitarian revolution' that separates humans from our closest relatives, the great apes. The model suggests that information from within-group conflicts leads to the emergence of cooperative alliances and social networks.