Pioneer behaviorist John B. Watson believed that most fears are learned. To prove it, he deliberately set out in 1920 to condition an 11-month-old baby named Albert to fear white lab rats. Like most babies, little Albert was fearless and curious about the world. Watson, however, found that sudden loud noises caused Albert distress.
In a highly unethical experiment, Watson and a colleague used the sound of a hammer striking a steel bar to startle Albert whenever they presented him with a white lab rat. The moment Albert tried to touch the fury white animal, the bar was struck, scaring Albert. The more this grim experiment was repeated, the more afraid Albert became. Soon just the mere sight of a white rat caused him to cry. Worse, Albert's fear had generalized to other furry objects; seeing a fur coat, a dog, a rabbit, even a Santa Claus mask made Albert burst into tears.
Dr. Watson knew a month in advance that baby Albert would be leaving the hospital, but never attempted to remove his fear of furry objects. No one ever knew Albert's last name, nor if his fear persisted the rest of his life.