Zimbardo’s Prison Experiment
Imagine your personality changing completely in just a few days – turning you into either an aggressive prison guard or a broken prisoner. The infamous Stanford Prison Experiment demonstrated exactly this terrifyingly rapid transformation, revealing how power and confinement can expose the darkest corners of human nature. Beyond its scientific outcomes, the experiment offered a shocking moral lesson: anyone can become anything if power and environment influence them in the wrong way. What happens when we lose our humanity? Zimbardo’s experiment sought to answer this question – and it changed how we perceive authority forever.
Philip Zimbardo (1933–2024) was an American psychologist whose research focused on human behaviour and how it is shaped by social context. He is best known for the Stanford Prison Experiment, conducted in 1971 at Stanford University. Its purpose was to examine how power and social roles influence behaviour, particularly why conflicts arise between guards and prisoners in military prisons.
Zimbardo created a simulated prison on the university campus and randomly assigned twenty-one volunteers – none of whom had previously met – to act as guards or prisoners. Everything was conducted as it would have been in a real case: the students cast as ‘prisoners’ were arrested at their homes, their belongings confiscated at the police station, and then taken to the university blindfolded, where ‘guards’ – also students – were already waiting in uniform. The participants soon immersed themselves fully in their roles. Although physical violence was prohibited, the ‘guards’ punished rule-breaking prisoners with push-ups and other degrading tasks. Before long, a prison riot broke out, which triggered disturbing aggression among the ‘guards’: ringleaders were placed in solitary confinement and denied food.
The consequences were appalling. The guards became increasingly cruel, while the prisoners grew submissive and despairing. The experiment, originally intended to last two weeks, had to be terminated after only six days because of the guards’ escalating brutality and the prisoners’ mental breakdowns – despite none of them having any prior psychological issues.
The authenticity of the experiment remains disputed to this day. In 2018, investigative journalist Ben Blum released decisive audio evidence suggesting that the study had been manipulated: the supervisors had allegedly instructed the ‘guards’ to behave aggressively, ensuring results that supported their hypotheses. Zimbardo, however, steadfastly defended his conclusions, stating at the time: “No amount of evidence changes the value of the experiment’s conclusion – the recognition of how systemic and situational forces can influence individual behaviour, for better or for worse, often without the individual’s awareness.”
The shocking project – which even inspired a feature film (The Stanford Prison Experiment, 2015) – demonstrated, whether through influence or manipulation, how power and social roles can dehumanise people with alarming speed. It also showed how psychological forces can reshape social norms and moral boundaries.
Following the experiment, Zimbardo developed the concept of the power of the situation, arguing that behaviour is not determined solely by personality or internal motivation, but also by powerful social and environmental factors. In his view, external circumstances and situational pressures can profoundly shape human actions – sometimes even driving people to act against their own fundamental moral principles.