On the ethics of intervention in human psychological research: With special reference to the Stanford prison experiment

Abstract

Research was conducted recently (August 14-21, 1971) in which subjects assumed the roles of ‘prisoner’ or ‘guard’ for an extended period of time within an experimentally devised mock prison setting on the Stanford University campus. The projected twoweek study had to be prematurely terminated when it became apparent that many of the ‘prisoners’ were in serious distress and many of the ‘guards’ were behaving in ways which brutalized and degraded their fellow subjects. In addition, the emerging reality of this role-playing situation was sufficiently compelling to influence virtually all those who operated within it to behave in ways appropriate to its demand characteristics, but inappropriate to their usual life roles and values; this included the research staff, faculty observers, a priest, lawyer, ex-convict, and relatives and friends of the subjects who visited the prison on several occasions (for details see Zimbardo, Banks, Haney and Jaffe, 1973; Haney, Banks and Zimbardo, 1973). This research represents one of the most extreme experimental demonstrations of the power of situational determinants in both shaping behaviour and predominating over personality, attitudes and individual values. As such it extends the conclusions from Stanley Milgram’s research on obedience to authority (1974). But the ethical concerns voiced over Milgram’s treatment of placing subject-teachers in a conflict situation where they believed (incorrectly) that they were hurting another person are even more pronounced in the present case. Volunteer prisoners suffered physical and psychological abuse hour after hour for days, while volunteer guards were exposed to the new self-knowledge that they enjoyed being powerful and had abused this power to make other human beings suffer. The intensity and duration of this suffering uniquely qualify the Stanford prison experiment for careful scrutiny of violations of the ethics of human experimentation. The plan of this article is to: (a) Give a synopsis of the experiment to familiarize the reader with its basic features; (b) summarize one set of critical arguments levelled