What was the central research question the Stanford Prison Experiment was designed to answer?
A: Whether prisoners are more likely to reform in smaller prison populations
B: Whether prison violence stems from the dispositions of guards and prisoners, or from the situational pressures of the prison environment
C: Whether authoritarian personalities are more likely to volunteer for prison-related studies
D: Whether random assignment of roles in institutional settings leads to more equitable outcomes
Correct: Whether prison violence stems from the dispositions of guards and prisoners, or from the situational pressures of the prison environment
Zimbardo designed the study to test a dispositional vs. situational explanation for brutality and suffering in real prisons. At the time, a widespread assumption held that prisons were violent because they attracted and retained people with sadistic or anti-social dispositions — "bad apples." Zimbardo's situationist hypothesis was that the structure of the prison environment itself — the roles, rules, power asymmetries, and depersonalisation — could transform otherwise normal people into oppressors and victims. The random assignment of 24 mentally healthy, psychologically stable volunteers to guard or prisoner roles was intended to control for pre-existing personality differences.
How were participants assigned to the roles of "guard" or "prisoner" in the Stanford Prison Experiment?
A: Psychological testing determined which participants were best suited to each role
B: Volunteers who had previous contact with the criminal justice system were made prisoners
C: Participants were randomly assigned by a coin flip
D: Participants self-selected based on which role they preferred
Correct: Participants were randomly assigned by a coin flip
All 24 participants were randomly assigned by a coin flip on the morning the study began. This was a critical methodological feature: it meant that any differences in behaviour between guards and prisoners could not be attributed to pre-existing personality differences, since the groups were equivalent at the start. Guards were given uniforms, reflective sunglasses (to prevent eye contact and promote deindividuation), wooden batons, and whistles. Prisoners were arrested at their homes by real Palo Alto police officers (arranged by Zimbardo), booked, blindfolded, and brought to the "prison" — the Stanford basement — where they were issued smocks and given numbers instead of names.
Why was the Stanford Prison Experiment stopped after only six days, rather than the planned two weeks?
A: Zimbardo ran out of funding and could not pay participants for the remaining time
B: Guards began refusing to continue, citing moral objections to the treatment of prisoners
C: Several prisoners experienced severe emotional distress, and an outsider (Christina Maslach) confronted Zimbardo about the ethics of continuing
D: An independent review board inspected the facility and ordered it shut down on legal grounds
Correct: Several prisoners experienced severe emotional distress, and an outsider (Christina Maslach) confronted Zimbardo about the ethics of continuing
By day five, multiple prisoners had experienced extreme emotional distress — one had been released early with a psychosomatic rash, another had gone on a hunger strike, and others showed symptoms of acute psychological disturbance. Critically, Zimbardo himself had become so absorbed in his role as prison superintendent that he had lost his perspective as a researcher. It was Christina Maslach — a graduate student (and Zimbardo's future wife) — who, after touring the facility, confronted him: "What you are doing to those boys is a terrible thing." Her challenge prompted him to terminate the study the following morning. Zimbardo later acknowledged that Maslach's intervention was the ethical turning point.
What does the term "deindividuation" mean, and how did the SPE illustrate it?
A: A process by which individuals become more individualistic under group pressure; guards expressed this by asserting personal authority
B: A loss of self-awareness and individual identity in group or role contexts, which can lower inhibitions against anti-social behaviour
C: A cognitive bias in which individuals fail to consider the individuality of outgroup members
D: A personality trait associated with reduced empathy, which the screening process failed to eliminate
Correct: A loss of self-awareness and individual identity in group or role contexts, which can lower inhibitions against anti-social behaviour
Deindividuation refers to a reduction in self-awareness and personal identity in group or institutional contexts, often facilitated by anonymity or uniform dress. In the SPE, both guards and prisoners underwent deindividuation processes. Guards wore identical uniforms and mirrored sunglasses — removing their identifiable faces — which appeared to lower inhibitions and make abusive behaviour easier. Prisoners were stripped of their clothes, given smocks and numbers (their names were never used), and forced to wear nylon caps over their hair — a process of depersonalisation that contributed to passivity and reduced resistance. The uniforms were deliberately designed to promote role immersion.
What was a major methodological criticism of the SPE that emerged in investigative reporting by journalist Ben Blum (2018)?
A: The experiment was entirely fabricated and never actually took place
B: Zimbardo had secretly recorded guards' private conversations to influence their behaviour remotely
C: Guards were explicitly coached by Zimbardo's research assistant to be tough and mean, undermining the spontaneous nature of their behaviour
D: All participants were psychology students who already knew about Milgram's experiment and were role-playing what they expected
Correct: Guards were explicitly coached by Zimbardo's research assistant to be tough and mean, undermining the spontaneous nature of their behaviour
In 2018, journalist Ben Blum gained access to audio recordings from the original study and published a critical investigation. The recordings revealed that Zimbardo's research assistant David Jaffe had explicitly instructed guards before the study began to be tough, and to act as if they had power over the prisoners. One guard — Dave Eshelman, who became the most aggressive — later confirmed he had been consciously acting out a character inspired by the film Cool Hand Luke, rather than genuinely responding to situational pressures. These revelations significantly undermined the standard interpretation of the SPE: if guard behaviour was partly scripted rather than spontaneously situationally generated, the study's central claim — that roles alone transform people — is far more questionable.
The SPE is often invoked as an explanation for the Abu Ghraib prison abuses in 2003–2004. What is the core argument made by Zimbardo in this context?
A: That US soldiers at Abu Ghraib had sadistic personalities that were poorly screened for, paralleling how the SPE failed to screen out authoritarian participants
B: That the systemic conditions at Abu Ghraib — institutional power, dehumanising practices, lack of oversight — created a situational environment that enabled ordinary soldiers to commit abuses
C: That the Abu Ghraib abusers had all been exposed to violent media, which increased their baseline aggression in the same way modelling affected Bobo Doll children
D: That Abu Ghraib occurred because participants were placed in the agentic state by military hierarchy, exactly replicating Milgram's obedience mechanism
Correct: That the systemic conditions at Abu Ghraib — institutional power, dehumanising practices, lack of oversight — created a situational environment that enabled ordinary soldiers to commit abuses
Zimbardo testified as an expert witness at the court-martial of Abu Ghraib guard Ivan "Chip" Frederick, and later published The Lucifer Effect (2007), where he applied the SPE framework directly to Abu Ghraib. His argument was that systemic situational factors — dehumanising labels for prisoners ("terrorists," "enemy combatants"), absence of oversight, unclear rules of engagement, stress, fatigue, and institutional sanction for "softening up" detainees — created conditions analogous to the SPE, turning ordinary soldiers into abusers. Critics argued this unduly shifted responsibility from individual perpetrators to abstract "situations," and that Zimbardo's analysis served partly as a defence strategy.
Which ethical problem was most specific to Zimbardo's dual role in the SPE?
A: He was a paid consultant to the California Department of Corrections, creating a financial conflict of interest
B: He simultaneously acted as lead researcher and prison superintendent, compromising his ability to observe and intervene objectively
C: He published the results without obtaining consent from participants who had left the study early
D: He used photographs of the participants without anonymising their identities in the published paper
Correct: He simultaneously acted as lead researcher and prison superintendent, compromising his ability to observe and intervene objectively
One of the most serious ethical problems with the SPE was Zimbardo's conflict between his role as principal investigator (responsible for participant welfare, with an obligation to stop the study if harm occurred) and his self-appointed role as prison superintendent (invested in maintaining the fiction of the prison environment). By immersing himself in the role, he became unable to perceive the situation from the outside — a form of role absorption he later used as evidence for his situationist theory but which simultaneously explains his failure to act earlier. When an outside review board visited and raised ethical concerns, Zimbardo initially dismissed their concerns. Modern research ethics mandates strict separation between these roles.
What broader theoretical conclusion does the SPE (at face value) support within social psychology?
A: The dispositionist view: that personality traits are the primary determinants of social behaviour
B: The situationist view: that contextual and structural factors can override individual character and values
C: The trait-situation interaction model: that the effect of situations depends entirely on pre-existing personality differences
D: The biosocial model: that hormonal responses to power and submission are the primary drivers of institutional behaviour
Correct: The situationist view: that contextual and structural factors can override individual character and values
The SPE is the canonical demonstration in support of situationism — the theoretical position (associated with Kurt Lewin, Stanley Milgram, and Zimbardo himself) that situational and structural factors exert far more influence on human behaviour than dispositional personality traits. The random assignment of participants ensured that personality could not explain the differences between guards and prisoners, making the role structure and institutional context the only available explanatory variables. This sits in contrast to "dispositionism" — the commonsense tendency to attribute others' behaviour to their character. Lee Ross named this error the Fundamental Attribution Error: we over-attribute behaviour to persons and under-attribute it to situations, a bias the SPE was designed to challenge.
The Stanford Prison Experiment
What was the central research question the Stanford Prison Experiment was designed to answer?
About this quiz
In August 1971, Philip Zimbardo and colleagues at Stanford University converted the university's psychology department basement into a mock prison. Twenty-four healthy, psychologically stable male volunteers were randomly assigned to play either guards or prisoners for what was intended to be a two-week study.
The experiment was terminated after just six days. Guards had become increasingly authoritarian and abusive; prisoners showed emotional breakdown and passive despair. Zimbardo himself had become so immersed in the role of "Prison Superintendent" that he initially resisted calls to stop. The study became one of the most cited — and most contested — in the history of social psychology.