David P. Barash in the Chronicle of Higher Education:
“No fair” must rank among the loudest and most readily evoked complaints. Nor is the din of inequity limited to children. Consider the widespread anger generated by the Wall Street and AIG bailouts: Regardless of whether they were justified as national policy, those and other departures from perceived evenhandedness have a long history of rousing departures from citizen complacency, and even from civility. Ditto for outrage over executives getting outsized bonuses and golden parachutes while the rest of us are left to soldier on as best we can.
In evolutionary terms, what's going on here?
Another way of asking that question is to turn it around. Why do we feel so violated? Lixing Sun, a professor of biology at Central Washington University, thinks we have a “fairness instinct.” And he may be right. He maintains that high on the roster of human propensities is a “Robin Hood mentality” that characterizes our species and qualifies as one of those “mental modules” that evolutionary psychologists consider part of our likely biological inheritance.
More here. [Thanks to Ali Altaf.]