<P> Guards and prisoners had been chosen randomly from the volunteering college students . Some participants developed their roles as the officers and enforced authoritarian measures and ultimately subjected some prisoners to psychological torture . Many of the prisoners passively accepted psychological abuse and, by the officers' request, actively harassed other prisoners who tried to stop it . Zimbardo, in his role as the superintendent, allowed abuse to continue . Two of the prisoners left mid-experiment, and the whole exercise was abandoned after six days following the objections of graduate student Christina Maslach, whom Zimbardo was dating (and later married). Certain portions of the experiment were filmed, and excerpts of footage are publicly available . </P> <P> Zimbardo and his team aimed to test the hypothesis that the inherent personality traits of prisoners and guards are the chief cause of abusive behavior in prison . Participants were recruited and told they would participate in a two - week prison simulation . The team selected the 24 males whom they deemed to be the most psychologically stable and healthy . These participants were predominantly white and of the middle class . The racial and fiscal demographics of the prisoners is currently unknown . The group was intentionally selected to exclude those with criminal backgrounds, psychological impairments, or medical problems . They all agreed to participate in a 7 - to 14 - day period and received $15 per day (approximately $94 in 2018). </P> <P> The experiment was conducted in a 35 - foot (10.5 m) section of a basement of Jordan Hall (Stanford's psychology building). The prison had two fabricated walls, one at the entrance, and one at the cell wall to block observation . Each cell (6 × 9 feet, or 1.8 × 2.7 m), contained only a cot for the prisoners . In contrast, the guards lived in a very different environment, separated from the prisoners . They were given rest and relaxation areas, and other comforts . </P> <P> Twelve of the 24 participants were assigned the role of prisoner (9 plus 3 alternates), while the other 12 were assigned the role of guard (also 9 plus 3 alternates). Zimbardo took on the role of the superintendent, and an undergraduate research assistant the role of the warden . Zimbardo designed the experiment in order to induce disorientation, depersonalization, and deindividuation in the participants . </P>

Where did the stanford prison experiment take place