In the third section, Revenge of the Nerds, Pinker notes that we control the fate of tigers, not vice versa, and explains our edge: we are visual animals, live in groups, have hands and upright posture, and go hunting for meat, a complete protein that can best be stored in the bodies of other hunters who will return the favor. This sharing led to male coalitions and reciprocity. Today we are all birds of a feather because 60,000 years ago we dwindled to 10,000 because of some natural disaster, and "evolution is rapid when scattered populations exchange migrants" (p. 205). Claims by social scientists that new kinds of adaptation and selection have extended the biological kind are misleading, according to Pinker: "Human vice is proof that biological evolution . . . is a thing of the past" (p. 207). Some of us buy drugs instead of food, put off childbearing to achieve job status, seek pornography in place of mating, and eat ourselves to death.