Alyssa Crittenden: UNLV

Human prosociality is one of the defining characteristics of our species, yet the developmental origins of altruistic behavior remain little understood. The evolution of widespread food sharing in humans helped shape cooperation, family formation, life history, language, and the development of economies of scale. While the behavioral and ecological correlates of food sharing among adults are widely studied, very little is known about what motivates children to share food. Here, in the first study to analyze food collection and distribution of hunter-gatherer children, a higher degree of genetic relatedness between sharing partners correlates with both a higher frequency of sharing and a greater amount of food shared. Among genetically unrelated sharing partners, reciprocity appears to motivate food sharing. These results support recent suggestions that prosocial behaviors and egalitarianism develop strongly in middle childhood when children acquire the normative rules of their society.
http://www.bec.ucla.edu/crittenden_ucla_oct_2011.pdf