From The Righteous Mind: Why Good People Are Divided by Politics and Religion, by Jonathan Haidt

Part III is about the third principle: Morality binds and blinds. The central metaphor of these four chapters is that human beings are 90 percent chimp and 10 percent bee. Human nature was produced by natural selection working at two levels simultaneously. Individuals compete with individuals within every group, and we are the descendants of primates who excelled at that competition. This gives us the ugly side of our nature, the one that is usually featured in books about our evolutionary origins. We are indeed selfish hypocrites so skilled at putting on a show of virtue that we fool even ourselves.

But human nature was also shaped as groups competed with other groups. As Darwin said long ago, the most cohesive and cooperative groups generally beat the groups of selfish individualists. Darwin’s ideas about group selection fell out of favor in the 1960s, but recent discoveries are putting his ideas back into play, and the implications are profound. We’re not always selfish hypocrites. We also have the ability, under special circumstances, to shut down our petty selves and become like cells in a larger body, or like bees in a hive, working for the good of the group. These experiences are often among the most cherished of our lives, although our hivishness can blind us to other moral concerns. Our bee-like nature facilitates altruism, heroism, war, and genocide.

Once you see our righteous minds as primate minds with a hivish overlay, you get a whole new perspective on morality, politics, and religion. I’ll show that our “higher nature” allows us to be profoundly altruistic, but that altruism is mostly aimed at members of our own groups. I’ll show that religion is (probably) an evolutionary adaptation for binding groups together and helping them to create communities with a shared morality. It is not a virus or a parasite, as some scientists (the “New Atheists”) have argued in recent years. And I’ll use this perspective to explain why some people are conservative, others are liberal (or progressive), and still others become libertarians. People bind themselves into political teams that share moral narratives. Once they accept a particular narrative, they become blind to alternative moral worlds.