Editor's Note: This post is the first in a four-part series of essays for Scientific American by primatologist Frans de Waal on human nature, based on his ongoing research. De Waal and other researchers appear in a series of Department of Expansion videos focusing on the same topic.

How often do we see rich people march in the street shouting that they're earning too much? Or stockbrokers complaining about the "onus of the bonus"? Protesters typically are blue-collar workers yelling that their jobs shouldn't go overseas or that they should earn more. A more exotic example was the 2008 march through the capital of Swaziland by poor women who felt that the king's wives had overstepped their privileges by chartering an airplane for a shopping spree in Europe.

Fairness is viewed differently by the haves and have-nots. The underlying emotions and desires aren't half as lofty as the ideal itself. The most recognizable emotion is resentment. Look at how children react to the slightest discrepancy in the size of their pizza slice compared with their siblings'. They shout, "That's not fair!" but never in a way transcending their own desires.

An experiment with capuchin monkeys by Sarah Brosnan, of Georgia State University's CEBUS Lab, and myself illuminated this emotional basis. These monkeys will happily perform a task for cucumber slices until they see others getting grapes, which taste so much better. They become agitated, throw down their measly cucumbers, and go on strike. A perfectly fine vegetable has become unpalatable! Not all economists, philosophers and anthropologists were happy with our interpretation, because they traditionally consider the "sense of fairness" uniquely human. But by now there are many other experiments, even on dogs, that confirm our initial findings.

Obviously, things get extremely political if one claims that a desire for income equality has evolutionary backing, but it is hard to deny that the collapse of the world economy in 2008 was partly due to a massive misjudgment of human nature. We're considerably less selfish and more social than advertised.


Frans de Waal, PhD, is a Dutch-American primatologist known for his popular books, such as Chimpanzee Politics: Power and Sex among Apes (1982) and The Age of Empathy: Nature's Lessons for a Kinder Society (2009). He teaches at Emory University in Atlanta where he directs the Living Links Center at the Yerkes National Primate Research Center. He has been elected to the National Academy of Sciences and the Royal Netherlands Academy of Arts and Sciences.

The views expressed are those of the author and are not necessarily those of Scientific American.


Video credit: Department of Expansion