Certainly, if you look at human behavior around the world, you have to admit that we can be very aggressive.

War had always seemed to me to be a purely human behavior. Accounts of warlike behavior date back to the very first written records of human history; it seemed to be an almost universal characteristic of human groups.

It's not what happens to us, but our response to what happens to us that hurts us.

The crime of suicide lies rather in its disregard for the feelings of those whom we leave behind.

It was both fascinating and appalling to learn that chimpanzees were capable of hostile and territorial behavior that was not unlike certain forms of primitive human warfare.

Human behavior is incredibly pliable, plastic.