A chimpanzee who is really gearing up for a fight doesn't waste time with gestures but just goes ahead and attacks.

If you ask anyone, what is morality based on? These are the two factors that always come out: One is reciprocity, … a sense of fairness, and the other one is empathy and compassion.

Why not assume that our humanity, including the self-control needed for livable societies, is built into us? Does anyone truly believe that our ancestors lacked social norms before they had religion? Did they never assist others in need, or complain about an unfair deal? Humans must have worried about the functioning of their communities well before the current religions arose, which is only a few thousand years ago.

The hamadryas baboon is a harem holder where one male mates with multiple females.

If you are a cooperative animal you need to watch what you get. If you, or even a whole community, invest in something but then a few individuals receive a much larger return, it's not a good arrangement. If it happens consistently, it's time to look for an arrangement that is more beneficial. That's why we're so sensitive to how rewards are being divided.

I've argued that many of what philosophers call moral sentiments can be seen in other species. In chimpanzees and other animals, you see examples of sympathy, empathy, reciprocity, a willingness to follow social rules. Dogs are a good example of a species that have and obey social rules; that's why we like them so much, even though they're large carnivores.

If you want to design a successful human society you need to know what kind of animal we are. Are we a social animal or a selfish animal? Do we respond better when we're solitary or living in a group?