Yerkes researchers first to recognize sense of fairness in nonhuman primates:

"In the first experimental demonstration of its kind, researchers led by Sarah Brosnan and Frans de Waal, PhD, at the Yerkes National Primate Research Center of Emory University, and the Living Links Center, have shown nonhuman primates respond negatively to unequal reward distribution, a reaction often seen in humans based on their universal sense of fairness. While researchers have long recognized the sense of fairness within the human species, Brosnan and de Waal are the first to confirm this trait in nonhuman primates. The findings appear in the September 18 issue of Nature.

These new findings, coupled with previous scientific data that demonstrate a direct link between nonhuman primate behavior and that of humans, support a new school of thought that economic decision-making is based as much on an emotional sense of fairness as on rational considerations."

See Crime and Punishment for some human experiments.