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

I think that moral philosophy is useful for framing questions, but terrible at answering them. I think moral psychology is booming right now, and we're making a lot of progress on understanding how we actually work, what our moral nature is.

I think the greatest work in social psychology from the 1950s and '60s is enormously important. I wish every high school kid could take a course in social psychology. I think we're making enormous strides in understanding the brain. These aren't yet giving us great insights, but I feel like we're on the verge of it. In five or ten years this basically searching the brain is really going to change things.

[W]hen a group of people make something sacred, the members of the cult lose the ability to think clearly about it. Morality binds and blinds.

America is very much about individual happiness, the right to expression, self-determination. In America you do need to point to harm befalls victims before you can limit someone else's rights.

I began graduate school in the late 1980s, and my goal was to understand how morality varied across cultures and nations. I did some research comparing moral judgment in India and the U.S.A.

We are like a rider on top of a gigantic elephant. We can steer the elephant, and if he's not busy, he'll go where we want, but if he has other desires, he'll often go where he wants. How can one control the elephant? In part, this comes with maturity. In part, this comes with the development of your frontal cortex, so the frontal areas of the brain are especially involved in self-control, in suppressing your initial instinct to act. This is why teenagers are so impulsive. So it's terrible to allow the death penalty for teenagers, because they really don't have working brains yet.