The Stanford Prison Experiment assesses “the extent to which the external features of an institutional setting [can] override the internal dispositions of the actors in that environment” (195). The experiment has become famous for exposing that bad systems and situations can cause good people to behave in evil ways alien to their nature. The loss of personal identity, the subjection to arbitrary continual control, the loss of privacy, and the sleep deprivation that the prisoners experienced during the experiment all caused what is now known as “learned helplessness” (195). Because the prisoners were screened prior to the experiment to ensure they did not import any pathologies, Zimbardo concludes that all “pathologies were elicited by the set of situational forces constantly impinging upon them in this prisonlike setting” (197).

Zimbardo identifies problems present in data analysis of the Stanford Prison Experiment: the sample size is small, video recordings are selective, causal directions are uncertain, and the experiment has no control group. The only independent variable is “the treatment of guard-versus-prisoner status” (197). Zimbardo concludes, however, that clear patterns emerge.

Prior to the experiment, subjects were evaluated on three different measures: “the F-Scale of authoritarianism, the Machiavellian Scale of interpersonal manipulation strategies, and the Comrey Personality Scales” (198).