Tjaden, P., & Thoennes, N. (1998). Stalking in America:
Findings from the National Violence Against Women
Survey.Washington, DC: National Institute of Justice,
Centers for Disease Control and Prevention.STANFORDPRISON EXPERIMENT
The Stanford Prison Experiment (SPE) has become a
classic in the social sciences for its dramatic demon-
stration of the power of situational processes over
individual dispositions of its participants. It pitted a
powerful set of situational variables, which together
comprised what is worse in the psychological experi-
ence of imprisonment, against the will to resist by a
group of normal, healthy young men playing roles of
prisoners or guards.
The SPE was conducted in 1971 by a group of
Stanford research psychologists, led by Professor
Phillip Zimbardo, and two of Zimbardo’s graduate
students, Curtis Banks and Craig Haney. The experi-
ment was designed to control for the individual person-
ality variables that were often used at that time to
explain behavior in prison and other institutional set-
tings. That is, the researchers in the SPE neutralized the
explanatory argument that pathological traits alone
could account for extreme and abusive behavior by
(a) selecting a group of participants who were psycho-
logically healthy and who had scored in the normal
range of the numerous personality variables that they
measured and selected for, and (b) assigning partici-
pants to either the role of prisoner or guard on a com-
pletely random basis. The behavior that resulted when
these otherwise healthy, normal participants were
placed in the extreme environment of a simulated
prison would have to be explained largely if not entirely
on the basis of the characteristics of the social setting or
situation in which they had been placed.
The setting itself was designed to be as similar to an
actual prison as possible. Constructed in the basement
of the Psychology Department at Stanford University,
the “Stanford County Prison” had barred doors on the
small rooms that served as cells, cots on which the pris-
oners slept, a hallway area that was converted to a
prison “yard” where group activities were conducted,
and a small closet that served as a short-term “solitary
confinement” cell that could be used for disciplining
unruly prisoners. The prisoners wore uniforms that
were designed to de-emphasize their individuality andunderscore their powerlessness. Guards, on the other
hand, donned military-like garb, complete with reflect-
ing sunglasses and nightsticks. These guards generated
a set of rules and regulations that in many ways resem-
bled those in operation in actual prisons, and prisoners
were expected to comply with their orders. However,
guards were instructed not to resort to physical force to
gain prisoner compliance.
Despite the lack of any legal mandate for the “incar-
ceration” of the prisoners and despite the fact that both
groups were told that they had been randomly assigned
to their roles (so that, e.g., guards knew that prisoners
had done nothing to “deserve” their degraded prisoner
status), the behavior that ensued was remarkably simi-
lar to behavior that takes place inside actual prisons and
surprisingly extreme in intensity and effect. Thus, ini-
tial prisoner resistance and rebellion was met forcibly
by guards, who quickly struggled to regain their power
and then proceeded to escalate their mistreatment of
prisoners throughout the study at the slightest sign of
affront or disobedience. In some instances, the guards
conspired to physically mistreat prisoners outside the
presence of the experimenters and to leave prisoners in
the solitary confinement cell beyond the 1-hour limit
that the researchers had set.
Conversely, prisoners resisted the guards’ orders at
first but then succumbed to their superior power and
control. Some prisoners had serious emotional break-
downs in the course of the study and had to be released;
others became compliant and conforming, rarely if ever
challenging the “authority” of the guards. Despite the
fact that the researchers could not keep the prisoners in
the study against their will (and they had been informed
at the outset of the study of their legal right to leave), as
the study proceeded, they “petitioned” the prison
“administrators” for permission to be “paroled” or
returned passively to their cells when their requests were
denied. By the end of the study, they had disintegrated
as a group. The guards, on the other hand, solidified and
intensified their control. Although some of the guards
were more extreme and inventive in the degradation
they inflicted on the prisoners, and others were more
passive and less involved, none of the guards intervened
to restrain the behavior of their more abusive colleagues.
Although the study was designed to last for two full
weeks, the extreme nature of the behavior that occurred
led the researchers to terminate it after only 6 days.
Controversial from the outset, and widely discussed
and cited since it was conducted, the study has come to
stand in psychology and related disciplines as a756 ———Stanford Prison ExperimentS-Cutler (Encyc)-45463.qxd 11/18/2007 12:44 PM Page 756