Even monkeys understand when they're not being treated fairly and will go on strike to address injustice.
In a paper published in the Sept. 18, 2003 issues of the prestigious journal "Nature", primatologists at Emory University discovered that Capuchin Monkeys understand the concept of justice.
Researchers taught the monkeys to swap small tokens in exchange for food rewards. At first, all the monkeys were given a slice of cucumber in exchange for the tokens. In the next phase of the experiment, researchers began to reward one monkey with a grape (a highly desirable food to the monkeys) and continued to reward the others with cucumbers.
The response of the monkeys was dramatic. Fifty percent of the time the monkeys refused to perform the task whatsoever. The other half of the time, the monkeys would complete the task but
refused to eat the cucumber. Some of the monkeys took the cucumber and then threw it out of their cages.
Researchers not that just the day before the monkeys were happy to eat the cucumbers. The only difference was that they saw another monkey receiving "better pay" for the same work. Researcher Sarah Brosnan noted that the monkeys never reacted negatively to their grape-receiving peer. The monkeys vented their frustration at the researchers (management).
Researchers speculate that during evolution, social cooperation may have provided an evolutionary advantage. A necessary part of this would be a "sense of fairness" based upon the comparison of one's own efforts and pay-offs with those of others.
Negative reactions occur when expectations are violated. Researchers posit that this helps explain why a sense of fairness and justice seems to be constant throughout human cultures.