A well-known demonstration of how complex thoughts work top down to shape human-kind perceptions was orchestrated nearly thirty years ago by David Rosenhan, a professor of law and psychology. He and six volunteers — three other psychologists, a psychiatrist, a painter, and a homemaker — checked themselves into mental hospitals, each claiming to hear a voice that kept saying three words: “empty,’ “hollow,” and “thud.” That was all they did to be psychiatrically interesting; they did not alter their behavior in any other way. In each of the twelve hospitals they tested, they were admitted without question as mental patients.
Once inside, the pseudopatients immediately stopped talking about their voices, and, if they were asked, claimed that they no longer heard them. Nonetheless, all were confidently labeled schizophrenics and kept confined for weeks. (The average stay was nineteen days; one person was kept for nearly two months.) In the context of the psychiatric ward, their ordinary actions were taken as symptoms. For example, when they paced (remember, they were stuck in the ward, which is kind of boring), they were described as nervous and on edge. One of the fakers told a psychiatrist that he’d been closer to his mother as a child but then had become closer to his father as a teenager. “Ambivalence in close relationships:” wrote the psychiatrist. The only people who suspected the experimenters of faking were other patients.
A second experiment reversed the situation. Rosenhan warned the staff of a teaching hospital that he would try to sneak in some pseudopatients, but he never managed to recruit any. Nonetheless, psychiatrists at the hospital labeled scores of people as fakes.