The Stanford Prison ExperimentAn Experiment in Social Psychology

AP PsychologyMr. Tusow

The Arrest• On a quiet Sunday morning

in August, a police car swept through the town picking up college students as part of a mass arrest for armed robbery and burglary.

• The suspects were picked up at their home, charged, spread-eagled against the police car, searched, and handcuffed.

Booking and Holding Cells• The car arrived at the police station, the suspects

were brought inside, formally booked, read their Miranda Rights, finger printed, and a complete identification was made.▫ The suspects were then taken to a holding cell where

they were left blindfolded for as long as two hours.

Volunteering for the Experiment• College students answered a newspaper ad asking for

volunteers in a study of the psychological effects of prison life, in an experiment designed by Philip Zimbardo, a Stanford psychology professor.

• More than 70 applicants answered the ad and were given diagnostic interviews and personality tests to eliminate candidates with psychological problems, medical disabilities, or a history of crime.▫ 24 college students from the U.S. and Canada who happened

to be in the Stanford area were selected and set to earn $15/day.

Constructing the Experiment• The prison was constructed by boarding up each end

of a corridor in the basement of Stanford's Psychology Department building. ▫ That corridor was "The Yard" and was the only place

where prisoners were allowed to walk around, eat, or exercise.

▫ Cells were made from laboratory rooms with specially made doors with steel bars and cell numbers.

Humiliation• Each prisoner was systematically searched and

stripped naked. He was then deloused with a spray, to convey the belief that they may have germs or lice.

Humiliation• The prisoner was then issued a uniform. The main

part of this uniform was a dress, or smock, which each prisoner wore at all times with no underclothes.

• On the smock, in front and in back, was his prison ID number.

• On each prisoner's right ankle was a heavy chain, bolted on and worn at all times.

Becoming a Prisoner• The chain on their foot was used in order to remind

prisoners of the oppressiveness of their environment. ▫ When a prisoner turned over, the chain would hit his

leg, waking him up and reminding him that he was still in prison.

• The process of having one's head shaved is designed in part to minimize each person's individuality. It is also a way of getting people to begin complying with the arbitrary, coercive rules of the institution.

Enforcing the Law• The guards were free, within limits, to do whatever they

thought was necessary to maintain law and order in the prison. ▫ The guards made their own set of rules.

• All guards were dressed in identical uniforms of khaki, and wore a whistle around their neck and a Billy club borrowed from the police. ▫ Guards also wore mirror sunglasses which prevented anyone

from seeing their eyes or reading their emotions.

In the Cells• The experiment began with nine guards and nine

prisoners in the jail. Three guards worked each of three eight-hour shifts, while three prisoners occupied each of the three barren cells around the clock.

• The cells were so small that there was room for only three cots on which the prisoners slept or sat, with room for little else.

Asserting Authority • At 2:30 A.M. prisoners were awakened from sleep by

blasting whistles for the first of many "counts." The counts served as a way to familiarizing the prisoners with their numbers. ▫ More importantly, they provided a regular occasion for

the guards to exercise control over the prisoners.

Physical Punishment• Push-ups were a common form of physical

punishment imposed by the guards, for infractions of the rules or displays of improper attitudes toward the guards or institution.

• One of the guards stepped on the prisoners' backs while they did push-ups, or made other prisoners sit on the backs of fellow prisoners doing their push-ups.

Asserting Independence• Because the first day passed without incident, the

guards were surprised and totally unprepared for the rebellion which broke out on the morning of the second day. ▫ Prisoners removed their stocking caps, ripped off their

numbers, and barricaded themselves inside the cells by putting their beds against the door

• The guards were angered and frustrated because the prisoners began to taunt and curse them. When the morning shift of guards came on, they became upset at the night shift who, they felt, must have been too lenient.

Putting Down the Rebellion• The guards called in reinforcements. The three

guards who were waiting on stand-by duty came in and the night shift of guards voluntarily remained on duty.

• The guards broke into each cell, stripped the prisoners naked, took the beds out, forced the ringleaders of the prisoner rebellion into solitary confinement.

Special Privileges• One of the three cells was designated

as a "privilege cell." The three prisoners least involved in the rebellion were given special privileges. ▫ Given back their uniforms and beds and

were allowed to wash and brush their teeth.

• Privileged prisoners also got to eat special food in the presence of the other prisoners who had temporarily lost the privilege of eating. ▫ The effect was to break the solidarity

among prisoners.

Consequences of Rebellion

• The prisoners' rebellion played an important role in producing greater solidarity among the guards. • It was no longer just an

experiment,

• Now guards saw the prisoners as troublemakers who were out to get them, who might really cause them some harm.

• In response to this threat, the guards began increasing their control, surveillance, and aggression.

Prisoner #8612• Less than 36 hours into the experiment,

Prisoner #8612 began suffering from acute emotional disturbance, disorganized thinking, uncontrollable crying and rage.

• After a meeting with the guards where they told him he was weak, but offered him “informant” status, #8612 returned to the other prisoners and said “You can't leave. You can't quit.”

• Soon #8612 “began to act ‘crazy,’ to scream, to curse, to go into a rage that seemed out of control.”▫ It wasn’t until this point that the

psychologists realized they had to let him out.

A Visit from Parents• The next day, they held a visiting hour for parents

and friends. They were worried that when the parents saw the state of they jail, they might insist on taking their sons home. ▫ Guards washed the prisoners, had them clean and polish

their cells, fed them a big dinner and played music on the intercom.

Stepping Things Up• After the visit, rumor spread of a mass

escape plan. Afraid that they would lose the prisoners, the guards and experimenters tried to enlist the help and facilities of the Palo Alto police department.

• The guards again escalated the level of harassment, forcing them to do menial, repetitive work such as cleaning toilets with their bare hands.

An Informant in the Prison

•The guards had become so immersed in the simulation they started getting paranoid. In an attempt to stop further “plots,” the guards planted an informant within the prison.

Falling Further From Reality

• Zimbardo invited a Catholic priest who had been a prison chaplain to evaluate how realistic our prison situation was.

• The chaplain interviewed each prisoner individually.

• The priest told them the only way they would get out was with the help if a lawyer.

Half the prisoners introduced themselves by number rather

than name.

Prisoner #819• The only prisoner who did not want to speak to the priest

was Prisoner #819, who was feeling sick, had refused to eat, and wanted to see a doctor rather than a priest.

• Eventually while talking to the priest, #819 broke down and began to cry hysterically, just as had the other two boys released earlier.

• The psychologists removed the chain off his foot, the cap off his head, and told him to go and rest in a room that was adjacent to the prison yard. They told him they would get him some food and then take him to see a doctor.

Prisoner #819• While this was going on, one of the

guards lined up the other prisoners and had them chant aloud:

• "Prisoner #819 is a bad prisoner. Because of what Prisoner #819 did, my cell is a mess, Mr. Correctional Officer."

• The psychologists realized #819 could hear the chanting and went back into the room where they found him sobbing uncontrollably.

• The psychologists tried to get him to agree to leave the experiment, but he said he could not leave because the others had labeled him a bad prisoner.

Back to Reality• At that point, Zimbardo said, "Listen, you are not

#819. You are [his name], and my name is Dr. Zimbardo. I am a psychologist, not a prison superintendent, and this is not a real prison. This is just an experiment, and those are students, not prisoners, just like you. Let's go."

• He stopped crying suddenly, looked up and replied, "Okay, let's go,“ as if nothing had been wrong.

An End to the Experiment• Christina Maslach, a recent Stanford Ph.D. brought in

to conduct interviews with the guards and prisoners, strongly objected when she saw our prisoners being treated so poorly. ▫ Out of 50 or more outsiders who had seen our prison,

she was the only one who ever questioned its morality. • Once she countered the power of the situation,

however, it became clear that the study should be ended.

Maslach was dating Zimbardo at the time. They are still married to this day.

In the End• “By the end of the study, the prisoners were

disintegrated, both as a group and as individuals. There was no longer any group unity; just a bunch of isolated individuals hanging on, much like prisoners of war or hospitalized mental patients. The guards had won total control of the prison, and they commanded the blind obedience of each prisoner.”

-Philip Zimbardo

The End of the Experiment•After only six days, the planned two-week

prison simulation was called off.

•Do we see similarities to present day?

Discussion Questions• What are the effects of living in an environment with

no clocks, no view of the outside world, and minimal sensory stimulation?

• Consider the psychological consequences of stripping, delousing, and shaving the heads of prisoners or members of the military. What transformations take place when people go through an experience like this?

• After the study, how do you think the prisoners and guards felt?

• If you were the experimenter in charge, would you have done this study? Would you have terminated it earlier? Would you have conducted a follow-up study?