Two scientists at Emory University recently published a study of “fair play” in capuchin monkeys. The study was quite ingenious. The scientists wanted to discover whether the monkeys had an inherent sense of fairness and whether they instinctively understood what lawyers and economists refer to as distributive justice.

The scientists trained the monkeys to exchange a token for pieces of food. They used slices of cucumber, a food the monkeys liked. After a period during which the monkeys became accustomed to the exchange ritual of token for cucumber, the scientists singled out one monkey and gave him a grape rather than a slice of cucumber. In the world of capuchin monkeys, grapes are highly desirable and seen as far more valuable than cucumbers. All of the other monkeys continued to be offered cucumber slices.

The scientists discovered that the other monkeys, when they saw that one individual was being given preferential treatment (getting a grape for the same token), revolted. Many refused to accept the cucumber and preferred to receive no food at all rather than be given an inferior food. Further, when the scientists began to give a single monkey a grape without receiving any token in return, 80 percent of the other monkeys simply walked away and refused to participate further.

What is so fascinating about this experiment is that it seems to indicate that monkeys have an inherent, “hard-wired” sense of exchange fairness and would rather receive no food than be given less desirable food than another monkey is offered for the same work. Further, the two Emory scientists’ results are matched by results of recent experiments on human beings who tend to react in the same way in similar circumstances.

Indeed, in the human experiments, scientists did brain scans of the volunteers and found that certain regions of the brain, ones that they believe to be ancient in evolutionary terms, were activated by the unjust acts. These regions, interestingly enough, have been identified as those that control the emotion of disgust.

Lawyers and business managers rarely study the work of animal scientists to understand their own fields, but these experiments have great significance for the ways in which we organize human society and social institutions. The fact that a sense of fairness is “hard wired” into primate brains may well indicate that there is a biological source for human conceptions of justice.

Throughout history, lawyers and political theorists have struggled with the notion of justice. Cicero, over 2,000 years ago, defined justice by the term suum cuique, which might be roughly translated as “to each his due.” If we look at our own society, it is clear that questions of distributional justice and fairness are pervasive.

Within the past few weeks, for instance, the Cancun international trade talks broke down because the developing nations felt that the industrialized nations were unwilling to share the world’s wealth fairly. In Congress, debates rage today as to how much government aid should be given to the poor and the elderly and infirm at the expense of the wealthy. At our universities, faculty and staff question whether salary structures are fair.

The fact is that the question of fairness in the allocation of goods is one of the most central to the human (and, apparently, primate) condition. Knowing that there is a biological basis for the sense of fairness makes it imperative for those in control of such decisions, legislators, administrators, managers, to recognize that they cannot ignore the outrage that individuals may feel about unfair allocations. It is too easy — and too often done — to call dissatisfaction at perceived unfairness in the allocation of money or goods to be simple envy or greed and to tell those who are unsatisfied to stop “whining.”

As the Emory scientists have discovered, when the unfairness reaches an unacceptable level, individuals will revolt, even if it means self-denial. In every sphere of human activity unjust allocation of wealth has eventually brought disaster, from the French revolution to the more recent corporate salary scandals. Is it that difficult to view the conflict over the outrageous compensation paid to the former head of the New York Stock Exchange in terms of the Emory study’s findings? I think not. Perhaps, those capuchin monkeys have something to teach us all.

Mike Hoeflich is a professor in the Kansas University School of Law.