During World War II, B.F. Skinner trained pigeons to peck at images of enemy ships so their pecks would steer a missile’s fins. This episode follows Skinner from his 1904 birth in Pennsylvania, where he built an elderberry sorting machine as a boy, through his failed attempt to become a novelist after Hamilton College, a period he called his dark years. Reading John B. Watson led him to Harvard psychology, where he built the operant conditioning chamber and the cumulative recorder to measure voluntary behavior and its consequences without observer bias.

With Charles Ferster he mapped schedules of reinforcement, finding that the variable ratio schedule, the logic of a slot machine, produced the most persistent behavior. He also documented superstitious behavior in pigeons. Project Pigeon worked in lab tests but lost out to radar, and his climate controlled air crib became a public relations disaster after a magazine titled his article Baby in a Box. His 1948 novel Walden Two and Beyond Freedom and Dignity argued against free will, and Noam Chomsky’s critique of Verbal Behavior helped launch the cognitive revolution. A 2002 survey named him the most influential psychologist of the 20th century.

• The seatbelt alarm as an everyday example of negative reinforcement
• Why Skinner found punishment only suppresses behavior temporarily
• Rumors about his daughter and the air crib that she spent years denying
• Temple Grandin’s criticism of his dismissal of brain neurology
• A lifetime achievement award from the American Psychological Association 10 days before his death in 1990