“Friendship, like other kinds of altruism, is vulnerable to cheaters, and we have a special name for them: fair-weather friends. These sham friends reap the benefits of associating with a valuable person and mimic signs of warmth in an effort to become valued themselves. But when a little rain falls, they are nowhere in sight.”

Canadian cognitive psychologist and public intellectual

Steven Arthur Pinker is a Canadian cognitive psychologist, psycholinguist, popular science author, and public intellectual. He is known for his work on the mind, language, and human nature, and for presenting those subjects to a wide general audience. Pinker supports evolutionary psychology and the computational theory of mind. He is the Johnstone Family professor of psychology at Harvard University, and his writing often returns to questions about how people think, speak, and understand the world.