The Stanford prison experiment (SPE) was an attempt to investigate the psychological effects of perceived power, focusing on the struggle between prisoners and prison officers. It was conducted at Stanford University between August 14–20, 1971, by a research group led by psychology professor Philip Zimbardo.

1. ZIMBARDO’S :
THE STANFORD PRISON EXPERIMENT
VEDANG VATSA
ROHEN AGARWAL
SHIVANUJ
SHIVAM

2. PROFESSOR PHILIP G. ZIMBARDO, PHD

3. STANFORD 1971

4. INTRODUCTION
The Stanford Prison Experiment was a landmark psychological study
of the human response to captivity, in particular, to the real world
circumstances of prison life.
It was conducted in 1971 by Philip Zimbardo of Stanford University.

5. -This study was funded by the US Navy
- The US Navy & the US Marine Corps were interested in investigating
the causes of conflict between guards and prisoners in naval
prisons.

6. THE PARTICIPANTS
• The researchers set up a mock prison in the basement of Stanford
University’s psychology building, and then selected 24 undergraduate
students to play the roles of both prisoners and guards.
• The group of 70 volunteers had no criminal background, lacked
psychological issues and had no major medical conditions.
• The volunteers agreed to participate for a one to two week period in
exchange for $15.00 a day.

7. THE SETTING AND PROCEDURES
• The simulated prisons included three six by nine foot prison cells.
• Each cell held three prisoners and included three cots.
• Other rooms across from the cells were utilized for the prison guards
and warden.
• One very small space was designated as the solitary confinement
room, and yet another small room served as the prison yard.

8. DESCRIPTIVE GROUPS
The group selected to be the guards were outfitted in “military style”
intimidating uniforms. They were also equipped with wooden batons
and mirrored shades, to prevent eye contact and make the guards
appear less human.
No physical punishment was allowed.

9. 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.

10. ABU GHRAIB PRISON (IRAQ)
• The study recently garnered attention after reports of the Abu Ghraib
prisoner abuses in Iraq became known.
• Zimbardo himself, suggest that the abuses at Abu Ghraib might be
real world examples of the same results observed in Zimbardo’s
experiment.

11. HUMILIATION
• The prisoners were 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. They were
to be addressed by and answer to, identity numbers only.
• On each prisoner's right ankle was a heavy chain, bolted on and worn at all
times.
• Shaved head

12. PRISON CELLS
• 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.
• At 2:30 A.M. prisoners were awakened from sleep by blasting
whistles for the first of many "counts."

13. PHYSICAL PUNISHMENT
• Push-ups
• 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.

14. ASSERTING AUTHORITY
• First day passed without any incident.
• Rebellion broke out on 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.

15. PUTTING DOWN THE REBELLION
• The guards broke into each cell, stripped the prisoners naked, took
the beds out, forced the ringleaders of the prisoner rebellion into
solitary confinement.
• Forcing them to do menial, repetitive work such as cleaning toilets
with their bare hands.

16. SPECIAL PRIVILEGES
• The three prisoners least involved in the rebellion were given special
privileges.
• Given back their uniforms and beds
• Allowed to wash and brush their teeth.
• Given 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.

17. PRISONER #8612
• Within 36 hours, Prisoner #8612 began suffering from acute
emotional disturbance, disorganized thinking, uncontrollable crying
and rage.
• “began to scream, to curse, to go into a rage that seemed out of
control.”

18. PRISONER #8612 : FALLING FURTHER
FROM REALITY
• Zimbardo invited a Catholic priest
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.

19. PRISONER #8612 : FALLING FURTHER
FROM REALITY
"Prisoner #819 is a bad prisoner. Because of what Prisoner #819 did, my
cell is a mess, Mr. Correctional Officer."
• 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.

20. 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.

21. 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.
• Once she countered the power of the situation, however, it became
clear that the study should be ended.

22. 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
”
“

23. CONCLUSION
• People will conform to the social roles they are expected to play.
• The role that people have in a situation has a significant effect on their
behavior.
• Effect of innate personality is weaker than the external situation.