Sociologists have long known that most of us are pretty nice. We work well in groups and take care of one another. We generally tell the truth, we look after the young and old. Fundamentally, we’re good-natured and full of heart. This spirit of camaraderie helps explain why we’re so successful as a species, and why today there are seven billion of us.
Most of us don’t seek out tales of murder, promiscuity and violence. It gives us the creeps. Although we acknowledge that a small percent...