The Stanford Prison Experiment (SPE) took place at a time when the sources of authoritarianism and evil were a focal concern in psychology. It emerged from a tradition of activist social psychological research beginning with Solomon Asch in the 1940s and extending through Stanley Milgram’s obedience experiments in the early 1960s. The SPE was a product of the research program of social psychologist Philip Zimbardo, a member of the Stanford psychology faculty since 1968. Discussions among Zimbardo’s students in spring 1971 led to a plan to simulate a prison environment. They converted portions of the basement of a University building into a combination booking room and jail. Zimbardo and a number of his graduate and undergraduate students took on supervisory roles. Before the Experiment began, paid participants recruited through newspaper advertisements were screened to eliminate obvious psychopathology, then randomly assigned to either the role of ‘guard’ or ‘prisoner.’ On the first experimental morning August 14, 1971, actual local police simulated an arrest of each of the prisoner participants. After they arrived, blindfolded, a simulated booking took place. Guards escorted them to the prison hallway where prisoners were required to strip and exchange their clothing for simple shifts and slippers. After a simulated spray delousing, they entered makeshift cells. After this, the Experiment evolved as an extended improvisation, by both the guards and prisoners, on prison-related themes. Episodes of deprivation, bullying, and humiliation emerged unplanned. Originally planned to run for two weeks, the Experiment lasted only six days, prematurely terminated when its supervising personnel judged that the simulation had gotten out of their control. The coincidence of its termination with the Attica prison uprising in New York led to its immediate dissemination in the news. Since then the SPE has become one of the most iconic psychological studies of psychology’s modern era. Although intended to expose and ameliorate bad prison conditions, its effectiveness in this regard diminished during a rapid shift in US prison policy, in the mid-1970’s, from reform to repression. Over succeeding decades, the Experiment continued to stimulate the popular imagination, leading to an extensive replication on British television and its portrayal in two feature films. Soon after its original publication, the SPE attracted criticisms of its methodology. After 2010, critical scrutiny of the SPE as well as similar iconic studies from the 1960s and 1970s increased, fueled by the growing ‘replication crisis’ in psychology. This most recent phase of criticism reflects not just a turn toward reflexive disciplinary self-criticism but also the increased availability of archival sources for examination. The SPE continues to excite both passionate support and equally passionate obloquy, much as have other comparable simulations of human social behavior.
S. Morra, C. Gobbo, Z. Marini, R. Sheese (eds.), Cognitive Psychology: Neo-Piagetian Perspectives (New York: Lawrence Erlbaum Associates, 2008).