The Stanford prison experiment is a controversial — but renowned — exploration into the importance of institutional factors and social expectations within a prison setting.

Social roles and social norms are an important part of a culture. They’re the shared expectations among a community, group, or society regarding behaviors in different circumstances.

Social norms guide your general actions in day-to-day life. They’re the standards all members are held to. Within social norms, social roles are expectations related to your position.

The Stanford prison experiment sought to gain insight into how social norms, social roles, and institutional factors, like power structure, influenced prison psychology.

In 1971, Dr. Philip Zimbardo headed up a research study at Stanford University known as the Stanford Prison Experiment.

He and his team of researchers were trying to answer which was most psychologically influential in a prison setting:

  • People: their individual personalities and behaviors
  • Institutional factors: rules, power dynamics, and routines

To assess this, 24 male college student volunteers were randomly selected to play the role of prisoner or guard in a prison simulation. Each participant was determined to be physically healthy, without underlying mental health conditions, and without a history of drug use or criminal activity.

A mock prison was constructed in the basement of the Stanford University psychology building. 12 men were assigned to be guards, and 12 were assigned as prisoners. They were given a short de-briefing beforehand, but there were no specific rules related to the position.

The guards, for example, were free to develop their own set of regulations they deemed necessary to maintain order in the mock prison. Prisoners were told to expect some harassment and lack of privacy typical to real prison settings.

Within days, things spiraled out of control. The guard group became progressively sadistic in their prisoner harassment and control tactics, and many within the prisoner group began to experience severe emotional and physical effects.

The experiment, which was slated to last 2 weeks, was terminated after only 6 days due to ethical concerns about the distress visible among the prisoner group.

Psychologically, both the prisoner group and the guard group experienced changes related to assigned roles.

They internalized their social roles to the point where guards believed themselves to be superior, and prisoners believed they had no choice but to tolerate inhumane treatment.

Within the first 36 hours of the Stanford prison experiment, one of the prisoner participants began experiencing:

Rather than being immediately released, he was offered leniency from the guards in exchange for becoming an informant. This served to worsen the man’s symptoms, and he told others in the prisoner group, “You can’t leave. You can’t quit,” which negatively impacted the entire group.

Eventually, his symptoms became so severe he was released from the experiment.

Zimbardo himself became caught up in his fictional role of prison superintendant, finding it difficult to objectively monitor both guards and prisoners and enact timely interventions.

Overall, most of the participants experienced major emotional distress while in the simulation related to feelings of:

Despite the intensity of the experience, no lasting trauma was reported in the extensive follow-up testing, and all participants regained their baseline emotional states.

The Stanford prison experiment is considered controversial for a number of reasons.

Ethical concerns top the list. Participants weren’t adequately prepared for or made aware of the level of mistreatment they could receive.

Research from 2019 also suggests the experiment de-briefing placed certain expectations on those in the guard group to act in cruel, authoritarian ways.

Lack of transparency with the study’s participants, the use of components in a similar project from several months earlier, and incomplete collection of data are also cited as common criticisms of the experiment.

Despite these hang-ups with how the research was conducted, the Stanford prison experiment remains a frequently referenced point in psychological study.

While it may not accurately represent all prison dynamics, especially post-prison reform, it does offer valuable insight into what may have been a reality of prison settings in the 1960s and 1970s. It also serves as a continual reminder of the impact incarceration can have on mental health.

Prison reform and the Stanford Prison Experiment

Prison reform in the United States that focused on human rights, particularly prisoner rights, peaked in the 1960s and 1970s after the civil rights movement. It called to attention the environment in US prisons, which was largely unregulated and featured issues with unusual punishments and dehumanizing conditions.

In many prisons of the time, guards were cruel and authoritarian. Prisoner rights weren’t a concern. Murder as a punishment happened.

In addition to questionable conditions in prisons at the time, the 1970s saw a mass incarceration movement as the War on Drugs gained traction. Communities of color were disproportionately affected due to racial profiling by authorities, and the increase in criminal convictions led to overcrowding — and a worsening of conditions — in many prisons.

The Stanford prison experiment served as a cautionary example of how average people could be changed by their environment. It shined light on the psychological effects of incarceration, especially in an authoritarian environment, and at a time when prison reform was crucial to human rights.

Though prison reform did improve conditions for people in the criminal justice system, the psychological effects are still a modern concern.

Some experts believe that exposure to violence, solitary conditions, and chronic stress of imprisonment may lead to post-incarceration syndrome, an informal condition similar to post-traumatic stress disorder (PTSD).

PTSD is already common among those in prison settings. A French study from 2020, for example, notes that nearly 18% of males and 40% of females in prison experience PTSD, a condition that specifically occurs from exposure to trauma.

The Stanford prison experiment was conducted in the 1970s as a way to assess how individual and institutional factors impact psychology within a prison setting.

Although it’s considered a controversial experiment that was terminated early due to ethical concerns, it may have been a valid representation of many prison experiences prior to prison reform in the US.

The Stanford experiment also serves as a reminder that the mental health of those in the prison system remains a modern concern and that institutional factors still negatively impact those in the justice system despite reform.