"These four kinds of behavior — empathy, the ability to learn and follow social rules, reciprocity and peacemaking — are the basis of sociality.

De Waal sees human morality as having grown out of primate sociality, but with two extra levels of sophistication. People enforce their society's moral codes much more rigorously with rewards, punishments and reputation building. They also apply a degree of judgment and reason, for which there are no parallels in animals."
Natural selection favors organisms that survive and reproduce, by whatever means. And it has provided people, he writes in "Primates and Philosophers," with "a compass for life's choices that takes the interests of the entire community into account, which is the essence of human morality."