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The Psychology of Evil
by Philip Zimbardo - Stanford University
Our topic today is an ugly one, one that we all hate to think about, to read about, to listen to. It is
Evil. It is not pleasant to think about the nature of evil, of collective violence, of genocide, ethnic
cleansing, mass rape, brutal tortures, and bestial acts of human against human that challenge our
basic conception of human nature.
From early Christian history and the personification of Lucifer as the embodiment of evil, the
dispositional analysis of evil has focused analytical attention on identifying those individuals who
are evil by nature, and indeed there are some people who have directed collective violence, such
as Hitler, Stalin, Idi Amin, and Pol Pot. But those evil men are dead, yet evil continues.
It is more profitable, I believe, for us to focus our analytical energies on understanding their
followers--why they killed for their leaders, or why, once they started the killing, their leaders
became irrelevant, and that once the machinery of mass murder had been installed and
lubricated, it required only persistent dedication to one's job and the knowledge that it is being
executed effectively. We don't need evil demons for those deeds, only compliant workers or
willing soldiers.
What is that line, that cosmic boundary, that one crosses to go from being a good person, a
dutiful citizen, to a mass murderer with no conscience for
evil deeds and no remorse for destroying human lives?
And how is this line maintained? What would it take for
you to slide across it? We want to believe it is
impermeable, with us here forever and them over there
permanently, when in fact, that line is permeable--we
good ones could become those bad ones.
My modest task is to outline some of the
psychological processes that I believe are involved in
human evil, more specifically, to share with you some
ideas I have about the social psychological strategies
and tactics that can facilitate the transformation of good,
or at least ordinary, people into monsters, who are
perpetrators of evil. I try to counteract the fundamental attribution error, the human tendency to
overemphasize the dispositional while simultaneously underplaying the situational. I do so by
demonstrating that seemingly trivial aspects of social situations can influence our behavior in
profound ways, more so than we can imagine or give credit for--in the extreme--that can make us
do the unimaginable.
Imagine a traitor is sentenced to death by firing squad and the government wants to recruit his
peers, civilians, to shoot him. Few volunteer. If, however, they add a condition that only one of six
guns will have a real bullet in the chamber, thus each gun would have only a small likelihood of
being the lethal weapon, typically more volunteer. Why? Employing the tactic of diffusion of
responsibility greases that line, and some good people are ready to slide across the boundary,
become killers for the state.
One Principle for Line Bending, More?
Indeed there are many situational variables that subtly change key elements of the behavioral
space and shift the behavioral dynamics away from standard operating procedures toward novel
relationships and contingencies for which the actor does not have a prepared script to guide
behavior down familiar paths--and so becomes more vulnerable to the demands of the
immediately present behavioral context. Let's see what this means in four experiments.
Obedience to Authority
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Stanley Milgram's Jewish heritage contributed to his intellectual and personal concern for
finding an answer to the question: "If Hitler asked you, would you execute a stranger?" Despite
cultural differences, historical-setting differences, and the absence of the charismatic power of
Adolf Hitler, could it be demonstrated that thousands of us could be led down the same path as
them, to inflict extreme harm on another human being? How could an experimental research
paradigm provide answers to such vital questions?
Milgram recruited more than 1,000 participants from all walks of life to be a part of his studies.
They would arrive individually in the lab and be told they were helping psychological science to
find new ways to improve memory through punishment and thereby help in the education
processes (Milgram, 1974).
Teacher, the role assigned to the participant, helps the Experimenter, who is wearing the white
lab coat, symbolic of his status, to connect the Learner, a lovable middle-aged man, to the
electrical shock apparatus; the victim is in an adjacent room. On the first trials, learning is going
well, the word associates are being recalled, and Teacher says, "Good, fine."
But then the Learner starts making errors and punishment begins, first small, then ever
escalating. As it does, the Learner begins complaining, then yelling and screaming. The Teacher
is upset, having never imagined it would come to this. Turning to the Experimenter, Teacher
dissents, indicating he or she does not want to continue, which is cast aside as the Teacher is
reminded of the contract agreed to previously. More shock, more yelling, complaining of a heart
condition, and insisting he wants to quit. "Who will be responsible if something bad happens in
there to the Learner, Sir?" asks the Teacher. "I will; please continue, Teacher." At 375 volts the
Learner screams, there is a loud thud, and then only silence from the shock chamber thereafter.
Teacher is now really distressed (the women often cry, the men wince), says the experiment
should be terminated because the Learner has stopped responding.
Not so easy. "Remember the rules," reminds the Experimenter, "Failure to respond is an error,
and all errors must be punished immediately with the appropriate level of reaction, Teacher." And
there are five more higher levels possible to the extreme of 450 volts.
Before starting his research, Milgram invited 40 psychiatrists to predict the percentage and
type of person who would indeed go all the way in this study that he described to them in detail.
In their collective wisdom based on their medical training in dispositional, individualistic analysis,
they concluded that fewer than 1% of the Teacher - Participants would go all the way, and they
would be the sadists.
So the psychiatrists were all wrong; everyone's predictions were all wrong. Not 1%
compliance, but 65% compliance--two thirds of the subjects went all the way up to the final level.
That quantification of evil went as high as 90% or down to 10% compliance across 18 studies in
Milgram's research program--each study varying one aspect of the social situation.
So what is the answer, that my friend and New York High School classmate, Stanley Milgram,
found to his initial question? Yes, sadly, by exploiting our deeply ingrained learned behavioral
patterns of obedience, ordinary people could be seduced, initiated into behaving in ways that
might lead to killing innocent victims.
Let me outline the lessons I think we should take to heart from this experiment, which help us
to understand some fundamental process in making that line between good and evil more
permeable:
 Start with an ideology (justifying beliefs for actions).
 Use authority to legitimate that ideology.
 Give people desirable roles to play with meaningful status.
 Have rules that channel behavioral options.
 Employ semantic distortion to disguise truth (help = hurt).
 Arrange for contractual agreement with the game rules before the game begins.
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 Make situation give permission to engage in usually taboo acts.
 Make initial harmful act minimal, minor, trivial.
 Enable subsequent acts to escalate only gradually, minimally, but their cumulative
impact can be deadly.
 Displace responsibility for consequences on authority or others.
 Get actors involved in action, in technology, in details, without time to think
through the meaning of their actions.
 Don't allow usual forms of dissent to work; undercut them so dissent does not lead
to disobedience.
 Put actors in novel setting, without familiar referents.
 Have authority transform gradually from just to unjust.
 Give no training in how to challenge unjust authority.
 Do not provide apparent means for exiting the situation.
Deindividuation
In much evil in the world there is no strong leader always present
insisting that you must go on to do evil; that would be inefficient.
Instead, the leader creates conditions that facilitate evil in his
absence, conditions of deindividuation:
 Take away people's sense of uniqueness and individuality,
because that encourages spontaneity, rebelliousness, and
independence.
 Do so by submerging them in groups.
 Put them in uniforms.
 Disguise them with hoods or masks.
Can we demonstrate experimentally that making people feel anonymous will facilitate their
crossing that line over to the evil side?
To go from that imagined reality to behavioral reality, I did a series of experiments on the
concept of deindividuation (Zimbardo, 1970), in which college students' identities were concealed
in a small-group setting, their names were replaced by numbers, their clothing covered with
baggy lab coats, and their faces covered by hoods, or masks. Their task was to shock other
participants who were allegedly in a related experiment on the effects of stress on creativity;
these other participants tried to be creative while being stressed by these random shocks that the
members of the observing group were administering to them. In the first study,
I stacked the cards against an easy outcome by having groups of women be the agents of pain
for other women who were their victims. Later studies used males and military personnel, with
comparable results. Those in a deindividuated state delivered twice as much shock as controls
who were individuated.
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Dehumanization
My colleague, Albert Bandura, and his students continued this line of research by extending
the basic paradigm here to study the minimal conditions necessary to create dehumanization
(Bandura, Underwood, & Fromson, 1975). What they manipulated was only the actors' perception
of their victims--no authority pressures, no induced anonymity. A group of college students
expected to help train another group of students from a nearby college by collectively shocking
them when they erred on the task.
Just as the study was about to begin, the participants overhead the assistant tell the
experimenter one of three phrases--Neutral: "The subjects from the other school are here."
Humanized: "The subjects from the other school are here; they seem 'nice.'" Dehumanized: "The
subjects from the other school are here, they seem like 'animals.'" Mind you, they never saw
those other students, or heard anything directly from them, it is only this label that they had to go
on in imaging what they were like.
On trial one, the manipulation failed to have a differential effect on their aggression, and had
the researchers ended the study there, we would conclude that dehumanizing labels have no
behavioral impact, but as the study wore on, it had a major impact. The boys, who imagined their
victims as "animals," progressively elevated their shock levels over each trial after the first,
significantly more than the neutral control. Humanizing labels helped to reduce the aggression
significantly below the level of the neutral control.
When the participants were interviewed subsequently about why they behaved as they did,
what the researchers found was that the experimental condition enabled them to become morally
disengaged, to activate a set of psychological mechanisms that minimized the evil of their deeds,
while justifying it in a variety of ways. So a one-word label can create a stereotype of the victim, of
the enemy, that also lowers the height of that line between good and evil and enables more good
people to cross over and become perpetrators.
The external validity of this construct has been demonstrated by the lynching and burning alive
of untold numbers of Black men in the U.S., usually based on fears of their sexual conquest of
White women, facilitated by the dehumanizing label of "nigger."
Stanford Prison Experiment
What happens when we aggregate many of these processes that
contribute to the making of perpetrators: dehumanize victims,
deindividuate potential perpetrators, put them in a new strange,
anonymous environment, and give the perpetrators total power and
render the victims powerless? The answer is: the Stanford Prison
Experiment, which contains further lessons in the transformation of
good people into evil perpetrators (Haney, Banks, & Zimbardo, 1973;
Zimbardo, Haney, Banks, & Jaffe, 1973). In this study, a group of
ordinary college students were divided arbitrarily into "prisoners" and
"guards." Hidden cameras captured what happened: the "guards"
became more sadistic, devising cruel mental tortures, while the
"prisoners" either broke down or succumbed in cowed and mindless
obedience. I had to end this 2-week study after only 6 days because it had become too real, too
volatile. [Editor's note: The website www.prisonexp.org (Zimbardo, 1999), on which the
photograph above appears, offers an Internet slide show about this experiment.]
Violence of War
We have seen how social psychologists have isolated variables that can contribute to the
creation of perpetrators, but how do leaders of nations do it? How do national policies and
agencies do it to transform idealistic, innocent children into those who hate other people enough
to want them all to cease to exist, to exterminate them, to eliminate them and their very memory
from the face of the earth forever? Briefly, it involves agents and agencies of socialization,
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propaganda, and education.
Socialization. Socialization means that parents and adult caretakers shape the values and
ideas of the next generation. It is the basic means of civilizing children, of transmitting the lessons
of the past to the current generation, of modeling what the culture says is the right way to behave
in order to be a good person. When parents become agents of the state whose agenda includes
learning to hate select others, and in doing so provide compelling reasons and examples for their
children to believe in and emulate, that is one powerful way for ruling elites to spread their ideals
and political agendas across generations to create a youth that will fight and die for their cause.
Propaganda. Central to genocide is the psychological and sociological construction of the
concept of the enemy, an abstraction into which the propagandist can embed all the fears and
loathing of the citizenry, all their primal anxieties about survival and well-being. Every nation that
goes to war must first construct the face of the enemy for its soldiers to want to kill and its citizens
to want to work and sacrifice to prevent its takeover of their land, home, way of life, women and
children, and even their god. Recall Bandura's research on the power of a dehumanizing label.
Education. All nations educate children to learn information that the state believes is vital for
them to know. What happens when that educational process becomes distorted so that biases
and self-serving values prevail and knowledge of the truth is suppressed? It happens to some
extent in most countries when they fail to include the history of their atrocities or defeats in history
texts. Beside these omissions, education is compromised when teachers and text writers are
subjugated to powerful national forces that instruct them to teach hate and lies and falsehoods to
children as if they were merely facts about the enemies of the state.
Where is That Elusive Line?
So what have we learned so far about that line between good and evil? Alexander
Solzhenitsyn offers an insight into where it can be found: "The line between good and evil lies in
the center of every human heart"--not in some abstract moral, celestial space, but right here in
each of our individual and collective beings.
Conclusion
We have seen that education can be corrupted and turn out mindless nazis and perpetrators
of evil, when the state controls what students and teachers must think. It is imperative that we
each make a personal commitment never again to allow education to be perverted into a
tool for prejudice, an instrument for demeaning human nature, or an intellectual weapon
for justifying the evils of inhumane treatment of our brothers and sisters of any race,
religion, ethnicity, or political persuasion. Education must be our salvation, not our
damnation.
Evil is not simply in the past and in far-off lands. There are still forces in our own country and
throughout the world that promote evil. We must not make them our enemies in the abstract, but
monitor their ideas and actions in the concrete, and do all in our power to oppose their distorted
values by promoting human understanding, compassion, and commitments that foster peace at
home and abroad. You must sustain a sense of moral and social intelligence, to always think
critically, to stand up for your beliefs regardless of the immediate consequences, to oppose unjust
authorities and reveal the true nature of fools. I urge you to make a life goal to be heroic, to learn
how to resist undesirable social pressures and be willing to stand alone. Otherwise, we join ranks
with the brute beast and get in line as passive witnesses to the next generation of dictators and
perpetrators of evil.
Recall the UNESCO Charter, which declares: "Since wars begin in the minds of men, it is in
the minds of men that we must erect the ramparts of peace."
Thus, the first step in preventing genocide begins by promoting peace, love, and
understanding in your minds and in mine. It is our first line of defense against evil, and it is the
source of strength we all need to resist the ever-present, pervasive, powerful forces in the world
that would lure us across that seductive line to descend into the realm of the next generation of
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evil perpetrators. Resist those pressures, and help others to also dissent, disobey, rebel.
So go in peace, Shalom.
References
Bandura, A., Underwood, B., & Fromson, M. E. (1975). Disinhibition of aggression through
diffusion of responsibility and dehumanization of victims. Journal of Personality and Social
Psychology, 9, 253-269.
Milgram, S. (1974). Obedience to authority: An experimental view. New York: Harper & Row.
Haney, C., Banks, W. C., & Zimbardo, P. G. (1973). Interpersonal dynamics in a simulated prison.
International Journal of Criminology & Penology, 1, 69-97.
Zimbardo, P. G. (1970). The human choice: Individuation, reason, and order versus
deindividuation, impulse, and chaos. In W. J. Arnold & D. Levine (Eds.), Nebraska Symposium on
Motivation: Vol. 17 (pp. 237-307). Lincoln: University of Nebraska Press.
Zimbardo, P. G. (1999). Stanford Prison Experiment Slide Show [On-line]. Available:
http://www.prisonexp.org
Zimbardo, P. G., Haney, C., Banks, W. C., & Jaffe, D. (1973, April 8). The mind is a formidable
jailer: A Pirandellian prison. The New York Times Magazine, 122, 38-60.
This article is condensed and adapted from Dr. Zimbardo's Psi Chi Distinguished Lecture, "The
Psychology of Evil: Seducing Good People Into Evil Deeds," delivered on March 31, 2000, at the
annual meeting of the Southeastern Psychological Association in New Orleans, Louisiana.
ABOUT THE AUTHOR: Philip G. Zimbardo, PhD, has been a professor of psychology at
Stanford University since 1968, after having taught previously at Yale University, New York
University (NYU), and Columbia University. Zimbardo received his BA from Brooklyn College
(1954) and his PhD from Yale University (1959). As author of more than 250 professional articles
and chapters and two dozen books, Zimbardo's ideas have influenced
many generations of colleagues, students, and the general public. His
popular introductory psychology text, Psychology and Life, going into its
16th edition, is the oldest continuously selling textbook in U.S.
psychology. His trade books, Shyness and The Shy Child, have been
best-sellers in the United States, translated into 10 foreign languages,
and influential in starting both new research and treatment of shyness,
especially in adults. Zimbardo designed, wrote, and hosted the awardwinning
PBS television series, Discovering Psychology, shown nationally
in colleges and high schools and now internationally, which he will soon
update and also add several new programs, including segments on
cultural psychology and cognitive neuroscience.
Dr. Zimbardo loves to teach and teaches intensively and extensively--
across the curriculum at Stanford and in colloquia and teaching
workshops. This is his sixth decade teaching introductory psychology
(since 1957). He has won numerous awards for his distinguished
teaching at Stanford and from other institutions, NYU, the American Psychological Foundation,
the Western Psychological Association, Phi Beta Kappa, and Division 2 of APA (Teaching of
Psychology). Zimbardo started a Psi Chi chapter when he was at NYU (Bronx campus) and
reactivated the Stanford chapter, serving as its faculty advisor for a decade. He has also given a
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number of Psi Chi addresses at regional and national conventions. In addition, he has received
awards for his writing, research, and video productions.
Zimbardo continues an active research program in the area of social psychology, focusing
especially on aspects of aggression and violence, the psychology of time perspective, the
dynamics of shyness, the psychology of cults, the origins of madness in normal people, and the
socialization of men into becoming torturers. His Stanford Prison Experiment on the dramatic
consequences of putting good students in mock prison has become a classic demonstration of
the power of social situations and a cornerstone in his general interest in the psychology of evil.
His current service as president of WPA and active campaign for the presidency of APA, along
with a full teaching and research schedule, keeps Zimbardo's passion for psychology flowing, and
"giving it away to the public" foremost on his agenda. See some of the free informative sites that
he has developed for psychologists (www.prisonexp.org; www.realpsychology.com; and his own
site, www.zimbardo.com) as well as the featured interview with him in the October 2000 issue of
Psychology Today magazine.
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Fall 2000 issue of Eye on Psi Chi (Vol. 5, No. 1, pp. 16-19), published by Psi Chi, The National
Honor Society in Psychology (Chattanooga, TN). Copyright, 2000, Psi Chi, The National Honor
Society in Psychology. All rights reserved.