In the early 1970s, a psychology professor at Stanford University named David L.
Rosenhan gathered a painter, a graduate student, a pediatrician, a psychiatrist, a
housewife, and three psychologists, and told them to check into different psychiatric
hospitals under aliases, with the complaint that they had been hearing voices. Apart from
their initial story, they were to tell the truth at all times and tell the staff at every
opportunity that the voices were gone. They were hospitalized, on average, for nineteen
