A fascinating interview with Professor Frans de Waal, a Dutch primatologist and ethologist and author of the book, Age of Empathy. de Waal makes a strong research-based case that  cooperation, altruism, and  a sense of fairness are much more powerful and common in driving our moral judgements than mere self-interest.  This apparently holds true in other primates and animals as well as humans.  Since virtually all of neo-classical, mainstream microeconomic theory is based on the assumption that only self-interest governs human behavior, this is significant. (red emphasis is mine).

Are we witnessing the end of an erroneous stream of thinking in which selfishness and self-preservation were seen as the only basic ‘natural instincts’ of all animal species?

PROF. FRANS DE WAAL: For the past three decades, scientists and popularizers have tried to tell us that we and all other animals are inherently selfish, and that the evolution of morality is an almost impossible affair, since nature cannot provide the caring for others needed for morality. I call this “Veneer Theory,” since it assumes that human morality and kindness is just a thin veneer over an

otherwise nasty human nature. This is a position that goes back to Thomas Henry Huxley, a contemporary of Darwin, and has been repeated over and over even though Darwin himself disagreed. Darwin saw human morality as continuous with animal social instincts, and my own work is a return to Darwinian thinking.I am supported in this now by many recent studies that indicate that humans (and other animals) are far more altruistic and cooperative than was assumed. The field has radically changed in recent years. Psychologists stress the intuitive way we arrive at moral judgments while activating emotional brain areas, and economists and anthropologists have shown humanity to be far more cooperative, altruistic, and fair than predicted by self-interest models. Similarly, the latest experiments in primatology reveal that our close relatives will do each other favors even if there’s nothing in it for themselves.

Chimpanzees and bonobos will voluntarily open a door to offer a companion access to food, even if they lose part of it in the process. And capuchin monkeys are prepared to seek rewards for others, such as when we place two of them side by side, while one of them barters with us with differently colored tokens. One token is ‘selfish,’ and the other ‘prosocial.’ If the bartering monkey selects the selfish token, it receives a small piece of apple for returning it, but its partner gets nothing. The prosocial token, on the other hand, rewards both monkeys. Most monkeys develop an overwhelming preference for the prosocial token, which preference is not due to fear of repercussions, because dominant monkeys (who have least to fear) are the most generous.

It is often thought that the microeconomic assumption of self-interest comes from Adam Smith.  It did in large measure, but not to the extent that modern mainstream microeconomic theory has taken it. Smith often wrote of the other motivations and their effects (see Theory of Moral Sentiments as well as Wealth of Nations), but economists have largely ignored them.  In particular in the 20th century when economists copied the mathematical models of Newtonian physics, it was convenient to ignore anything but the self-interest assumption as the motivation of all activity.