By 1971, many people in the
United States had participated in
protests and riots over issues like
civil rights and theVietnam war.
More young people were going
to jail, and at the same time,
more reports of police brutality
were being reported by the
press.This atmosphere inspired
the Stanford Prison experiment.
How does perceiving yourself
as an authority ﬁgure
inﬂuence your behavior?
3. The Experiment
The experiment was conducted
in 1971 and led Stanford
professor Philip Zimbardo. 24
male college students from the
U.S. and Canada were paid $15
per day to participate. These
candidates were chosen because
they were mentally and physically
healthy. They were also very
similar in age, education, race,
and social class. Because of their
similarities, at the start of the
experiment they considered
each other equals.
4. The Experiment
A random coin ﬂip assigned
50% of the subjects to the role
of “prison guard” and 50% to
the role of “prisoner.” The
guards were given no training
about how to be guards: they
made up their own set of
Over the course of the
experiment, they treated the
prisoners just as they would
be treated in a real jail…
7. Guard & Prisoner Behavior
• The punishments invented by the
guards became more severe and
creative as the experiment went on.
Disobedient prisoners were forced to
do push-ups, placed in solitary
conﬁnement, had their beds and
other items taken away, and were
• There were three “guard styles”
according to researchers: ﬁrst, there
were tough but fair guards who
followed prison rules. Second, there
were "good guys" who did little favors
for the prisoners and never punished
them. And ﬁnally, about 1/3 of the
guards were hostile, cruel, and
inventive in their forms of prisoner
• The prisoners initially resisted
being treated poorly (there was a
rebellion on the second day), but
when punishments became harsher,
• Prisoner #8612 experienced
uncontrollable crying, and rage, and
left the experiment. A few other
prisoners left later on.
• The experiment felt so real to the
participants that even though the
researchers said they could quit,
the prisoners felt that they couldn’t.
The researchers also started to
forget that the experiment wasn’t
real, and tried to cover up the
abuses they witnessed.
8. Experiment Conclusions
1. 1/3 of guards became
violent and cruel towards the
prisoners, showing us how an
authority position can alter
a person’s behavior.
2. Our behavior is drastically
affected by the situation: to
prevent evil behavior, don’t
focus on changing individuals,
focus on changing the
situations that enable them
to behave badly.
9. Social Forces Involved:
1. Deferral of responsibility to authority: when you think that
the authority ﬁgure will take responsibility forYOUR bad
2. Diffusion of responsibility: spreading the responsibility out
between many people. You feel less responsible for doing
something bad if other people are also involved.
3. Identity change: wearing a uniform makes you into a
“different person” than you are on a normal day. If many people
wear the same uniform, it makes you feel more anonymous.
4. Power of the situation: we all have good and bad character
traits that reveal themselves depending on the situation.
10. Discussion Questions:
1. After the study, how do you think the
prisoners and guards felt when they saw
each other in the civilian clothes again?
2.Was it ethical to do this study? Was it
right to trade the suffering experienced
by participants for the knowledge
gained by the research? Would it be
better if this study had never been
3.What actions could have prevented the
guards from abusing the prisoners?