Procedure: Participants randomly allocated to role of guard or prisoner. Mock prison created in basement Stanford Uni. 3 man rooms set up, several rooms for 'guards' quarters, small cupboard as 'punishment cell'. Guards met briefly before study began to be briefed by Zimbardo (superintendent). Forbidden from using physical aggression, work 3 man 8 hour shifts.
Prisoners told have basic living needs although told some basics would be removed (Privacy). Prisoners 'arrested' at home and taken to local police station in a police car. Blindfolded and taken to mock prison, stripped naked and sprayed with fake delousing spray. Prisoners not told experiment had started, stayed there 24 hrs a day. PP given uniforms, guards wore military style khaki shirt, trouser, reflective sunglasses, baton and whistle. Prisoners wore loose fitting smock with prison number, rubber sandals, ankle chain and a stocking/hat on head and not given underwear. Depersonalised the pp. Behaviour of prisoners/guards collected audio and video recordings and direct observation. Post-experimental interviews and questionnaires.