Stanford Prison Experiment

Note- sometimes written as SPE

What was the aim of Zimbardo’s Stanford Prison Experiment?

To investigate whether people conform to social roles of guard and prisoner in a simulated prison environment.

How were participants selected for the SPE?

24 male university students were screened for psychological health and randomly assigned to guard or prisoner roles.

Where was the Stanford Prison Experiment conducted?

In the basement of Stanford University, converted into a mock prison.

How were prisoners treated at the start of the study?

They were unexpectedly arrested at home, fingerprinted, stripped, deloused, and given prison uniforms and ID numbers.

What were guards instructed to do?

Maintain order in the prison but use no physical violence. They wore uniforms, mirrored sunglasses, and carried wooden batons.

How did Zimbardo participate in the experiment?

He acted as the prison superintendent, overseeing the study and interacting with participants.

What were the main findings of the SPE?

Guards quickly became abusive, humiliating prisoners, who became submissive, anxious, and depressed. The study ended after six days instead of two weeks.

What behaviours did prisoners display during the experiment?

Emotional breakdowns, rebellion, crying, and passivity — showing distress and loss of personal identity.

How did guards’ behaviour change during the experiment?

They became increasingly aggressive and authoritarian, using punishment and humiliation to maintain control.

What did Zimbardo conclude about conformity to social roles?

People readily conform to social roles, and situational factors can produce extreme behaviour even among psychologically stable individuals.

What explanation did Zimbardo give for the participants’ behaviour?

The power of the situation and social roles, rather than individual personality, caused the behaviour.

What are the strengths of the Stanford Prison Experiment?

Controlled conditions, high realism, and valuable insights into the influence of roles and institutions on behaviour.

What are the weaknesses of the SPE?

Ethical issues (psychological harm, lack of informed consent), experimenter bias, and lack of realism (role play).

What did Haslam and Reicher (2006, BBC Prison Study) find that challenges Zimbardo’s conclusions?

Participants did not automatically conform; some resisted authority, suggesting group identification and leadership are more important.

What ethical issues were raised by the SPE?

Participants experienced distress, humiliation, and loss of autonomy. Zimbardo’s dual role created conflict of interest.

How does the SPE apply to real

world events?

What criticisms exist regarding validity in the SPE?

Low internal validity due to Zimbardo’s involvement, and low population validity (small, male, American sample).

Was the SPE reliable or replicable?

Not reliably replicated; later studies (BBC, 2006) produced different results, questioning reliability.

How might demand characteristics have influenced the SPE?

Participants may have acted in ways they thought were expected rather than natural responses.

What alternative explanation challenges Zimbardo’s situational account?

Dispositional factors — some guards remained fair, suggesting personal morality also played a role.

What overall conclusion about social influence can be drawn from the SPE?

Behaviour can be shaped strongly by situational pressures and social roles, but individual differences and context still matter.