Participants were emotionally stable and without a criminal history
Guards and prisoners went through a process of experiencing deindividuation as they were given clothing and experiences that removed their personal identity
Guards wore uniforms, mirrored sunglasses and carried truncheons
Prisoners were 'arrested', stripped-searched and dressed in degrading smock uniforms
Prisoners were referred to by a number; not by their names and had 16 rules to follow which were enforced by the guards
Guards were instructed to keep prisoners under control without using physical violence
Guards had complete power over the prisoners, even deciding when they could go to the toilet
Zimbardo acted as the Head of the Prison, giving direction to the guards and managing prisoners
The observation was planned to run for 14 days