Collaboration encourages equal sharing in children but not in chimpanzees
Three year olds already share a toy with another child, if both have earned it together
Children as young as three years of age share toy rewards equally with a peer, but only when both collaborated in order to gain them. Katharina Hamann with an international team of researchers from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, Harvard University and the Michigan State University found that sharing in children that young is a pure collaborative phenomenon: when kids received rewards not cooperatively but as a windfall, or worked individually next to one another, they kept the majority of toys for themselves. One of humans’ closest living relatives, chimpanzees, did not show this connection between sharing resources and collaborative efforts. (Nature, 20th July 2011)
Therefore, “the ontogenetically first sense of distributive justice may be that participation in a collaborative effort demands an equal division of spoils”, says Katharina Hamann.
Chimpanzees, however, did not share more often after collaboration than in a windfall situation. Also in the wild, they only rarely actively collaborate for subsistence. Therefore, they may not have evolved a tendency to distribute resources more equally when those resources result from a collaboration.
“Taken together”, Hamann summarizes, “the primordial situation for human sharing of resources may be that which follows cooperative activities such as collaborative foraging, when multiple individuals must share the spoils of their joint efforts