Procedure: Field experiment, covert participant observation and self-report. 8 sane people, 3 women, 5 men 'pseudopatients'. Rosenhan was one. Psychology graduate, 3 psychologists, paediatrician, psychiatrist, painter and housewife. Made appointments at 12 different hospitals saying they heard voices saying "empty", "hollow", "thud". All gave false names and occupations. Once admitted behaved normally, said voices stopped. All made notes once admitted. Took part in ward activities, spoke and interacted with patients. Hid and flushed medication. If asked how felt say "fine and no longer experiencing symptoms". Had to convince staff they were sane to get out. In 4 hospitals approached staff and asked when they could leave. Interactions compared to control group between female researcher and staff members (directions). Pseudopatients recorded qualitative and quantitative data.