Evolutionary psychologist David M. Buss of the University of Texas at Austin: A high school dropout, he worked the night shift at a truck stop, pumping gas and contemplating the mating rituals of his co-workers--rituals he would later study in cultures around the world. Science beckoned after he returned to school and fell in love with a geneticist.
Philosopher of cognitive studies Daniel C. Dennett of Tufts University: The son of an OSS secret agent, he played jazz piano--once jamming with Chet Baker--and studied sculpture in Rome, where he met Federico Fellini. Dennett pursued a doctoral degree in philosophy, and his interest in consciousness led him to focus on the brain.
Neuroscientist Joseph LeDoux of New York University: As a child in Louisiana, he cleaned brains in his father's butcher shop, each time peeling away the organ's membrane to fish out the bullet that had killed the animal. LeDoux was majoring in business in college when he started taking psychology classes; a professor of biological psychology helped convince him to drop business for good.