Dividing into teams doesn't necessarily mean denigrating others. Studies of groupishness have generally found that groups increase in-group love far more than they increase out-group hostility.

It only takes twenty generations of selective breeding to create large differences or appearance and behavior in other mammals.

If you have high IQ, you're really good at finding post-hoc arguments to support your feelings of truthiness.

The mind is divided, like a rider on an elephant, and the rider’s job is to serve the elephant. The rider is our conscious reasoning-the stream of words and images of which we are fully aware. The elephant is the other 99 percent of mental processes-the ones that occur outside of awareness but that actually govern most of our behavior.

Anytime we're interacting with someone, we're judging them, we're sharing expectations, we think they didn't live up to those expectations.

Almost everything we do is automatic, yet we're not aware of that. We feel like there's a circle of light. We're like the drunk who lost his keys and is looking under the streetlight, and the cop says, "Where'd you lose your keys?" You say, "Back in the alley, but the light's so much better over here." The divided self refers to the fact that we are basically animals with animal brains. These animal brains run our lives. They're very good at it.

I did say that in-group, authority and purity are necessary for the maintenance of order, but I would never give them a blanket endorsement.