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Philip Zimbardo

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Nationality  American
Name  Philip Zimbardo

Role  Psychologist
Children  Adam Zimbardo
Philip Zimbardo Profile of a psychologist Philip Zimbardo Cognitive
Full Name  Philip George Zimbardo
Born  March 23, 1933 (age 82) (1933-03-23) New York City, New York, U.S.
Alma mater  Brooklyn College (B.A., Psychology, 1954) Yale University (M.S., 1955; Ph.D., Psychology, 1959)
Known for  Stanford prison experiment, The Time paradox, The Lucifer Effect, Abu Ghraib analysis, time perspective therapy, social intensity syndrome
Spouse  Christina Maslach (m. 1972), Rose E. Abdelnour (m. 1957–1972)
Parents  George Zimbardo, Margaret Bisicchia
Books  The Lucifer effect, Essentials of psycholo, Psychology: Core Conepts, The Psychology of Attitude, The Time Cure: Overcomi
Similar People  Christina Maslach, Stanley Milgram, Robert Cialdini, Solomon Asch, John B Watson

Philip zimbardo the psychology of evil

Philip George Zimbardo (born March 23, 1933) is a psychologist and a professor emeritus at Stanford University. He became known for his 1971 Stanford prison experiment and has since authored various introductory psychology books, textbooks for college students, and other notable works, including The Lucifer Effect, The Time Paradox and The Time Cure. He is also the founder and president of the Heroic Imagination Project.


Philip Zimbardo Susan Liautaud Dr Philip Zimbardo Psychology Professor

Philip zimbardo the psychology of time

Early years

Zimbardo was born in New York City on March 23, 1933, to a family of Italian immigrants from Sicily. He completed his BA with a triple major in psychology, sociology, and anthropology from Brooklyn College in 1954, where he graduated summa cum laude. He completed his MS (1955) and PhD (1959) in psychology from Yale University, where Neal E. Miller was his advisor. He taught at Yale from 1959 to 1960. From 1960 to 1967, he was a professor of psychology at New York University (University College of Arts & Sciences, Bronx NY). From 1967 to 1968, he taught at Columbia University. He joined the faculty at Stanford University in 1968.


Philip Zimbardo wwwzimbardocomphotosZimHeadshot2gif

In 1971, Zimbardo accepted a tenured position as professor of psychology at Stanford University. With a government grant from the U.S. Office of Naval Research, he conducted the Stanford prison study in which 24 clinically sane individuals were randomly assigned to be "prisoners" or "guards" in a mock dungeon located in the basement of the psychology building at Stanford (three additional college students were selected as alternates, only one of whom participated in the study). The planned two-week study into the psychology of prison life ended after only six days due to emotional trauma being experienced by the participants. The students quickly began acting out their roles, with "guards" becoming sadistic and "prisoners" showing extreme passivity and depression.

Philip Zimbardo Copy of Philip Zimbardo by ayden pearsall on Prezi

The volunteers knew they were being used in a study but they did not know when the study would be taking place, so the initial shock of being randomly arrested one morning and taken to the mock prison put them in a mild state of shock. On arrival, the "prisoners" were stripped, searched, shaved and deloused, which caused a great deal of humiliation. They were then issued uniforms, ID numbers, and escorted to their cells by the volunteer prison guards. The guards themselves were not given any specific instruction or guidelines for the way they were to treat the prisoners besides the fact they were not allowed to use corporal punishment. Instead, the psychologists allowed them to do whatever was needed to keep order in the prison. They were dressed in identical uniforms, wore a whistle around their neck and carried a night stick.


Philip Zimbardo Philip Zimbardo Big Think

At the beginning of the experiment, Zimbardo started off with nine guards and nine prisoners. All the original volunteers were kept as backups and three prisoners as well as three guards occupied the prison at a time. Their first night in the prison, the volunteer prisoners were awakened at 2:30 AM by the guards blowing their whistles.

The study shows that before the volunteer prisoners started showing signs of distress, they did not take the guards and their authority seriously. The prisoners mocked the guards, trying to regain their individuality. This, however, was short-lived. The prisoners soon realized that the attitude of the guards was very serious and that they demanded obedience. This began a long string of confrontational quarrels between the guards and prisoners. The guards used physical punishment and exercises, such as pushups, in order to show their authority to the prisoners.

In the morning of only the second day, a rebellion broke out among the volunteer prisoners. They ripped off their uniforms and locked themselves in their cells by pushing their beds up against the door. In response to this, the guards became very angry and called for backup. This surprised Zimbardo as well as the rest of the psychologists because they had not thought it would be taken this far. Guards who were not on duty were called in and the guards who were assigned to only the night shift stayed with the guards who came in all the way through their shift the next morning. The tactic the guards came up with was to fight back in order to discipline the unruly prisoners and make them obey. In response to the prisoners barricading themselves in their cells, the guards used fire extinguishers on them to get them away from the entrances.

Once the guards were able to get into the cells, they stripped the inmates naked, tore apart the beds and the cell, and put the prisoners who had started the rebellion in solitary confinement. As all nine guards could not be on duty at once, they began rewarding the prisoners for good behavior. The prisoners who had not been involved in starting the riot were allowed to lie in their beds, wash themselves and brush their teeth and eat while those who had started the riot were not allowed to. The guards continued to use tormenting tactics to divide the prisoners and forestall further organized resistance. In the case of one prisoner, who was a smoker, the guards were able to control his behavior because they decided when and if he was allowed to smoke.

Less than two full days into the experiment, one inmate began suffering from depression, uncontrolled rage, crying and other mental dysfunctions. The prisoner was eventually released after screaming and acting unstable in front of the other inmates. This prisoner was replaced with one of the alternates.

On the third day, the study allowed visiting hours for friends and family. The visitation was closely monitored and timed with many rules and restrictions. The next event that added to the prison experiment "drama" was a rumored escape plan that the prisoners were planning on carrying out directly after visiting hours. The prisoner was going to have some of his friends round up, break into the prison and free all of the prisoners. After one of the guards overheard this plan, an informant was placed in among the prisoners and the escape never happened. The prisoners who had been thought to have organized the escape were disciplined and harassed with more pushups and toilet cleaning.

At some point, even the prisoners who were thought of as role models and obeyed all of the guards' commands were being punished. Going to the bathroom was considered a privilege rather than a necessity, and those who acted out against the guards were made to urinate and defecate in a bucket in their cell.


By the end of the experiment, the guards had won complete control over all of their prisoners and were using their authority to its greatest extent. One prisoner had even gone as far as to go on a hunger strike. When he refused to eat, the guards put him into solitary confinement for three hours (even though their own rules stated the limit that a prisoner could be in solitary confinement was only one hour). Instead of the other prisoners looking at this inmate as a hero and following along in his strike, they chanted together that he was a bad prisoner and a troublemaker. Prisoners and guards had rapidly adapted to their roles, stepping beyond the boundaries of what had been predicted and leading to dangerous and psychologically damaging situations. Zimbardo himself started to give in to the roles of the situation. He had to be shown the reality of the experiment by Christina Maslach, his girlfriend and future wife, who had just received her doctorate in psychology. Zimbardo reflects that the message from the experiment is that "situations can have a more powerful influence over our behaviour than most people appreciate, and few people recognise."

At the end of the experiment, after all the prisoners had been released and the guards let go, everyone was brought back into the same room for evaluation and to be able to get their feelings out in the open towards one another. Ethical concerns surrounding the famous study often draw comparisons to the Milgram experiment, which was conducted in 1961 at Yale University by Stanley Milgram, Zimbardo's former high school friend.

This famous study is not well designed and has several serious experimental flaws:

  1. Zimbardo injected himself into the experiment by playing the role of the prison superintendent. This removed his objectivity as the principal investigator and created "experimenter bias".
  2. One of his colleagues questioned Zimbardo during the experiment, "What is your Independent Variable?" (That is, what factor is causing the effect?) This classic study is a clear example of "Confounding the Independent Variable". There are several possible Independent Variables and none of them are isolated clearly.
  3. The Dependent Variable (that is, the outcome behavior measurement) is not clearly defined or measured.

These three serious methodological problems must cause this study to be regarded much more as a "simulation" rather than as a true "controlled experiment". Therefore, this study could be about the effect of roles on behavior, the effect of an authority figure (i.e., Zimbardo) on obedience, the effect of sensory deprivation, the effect of unrestrained power, etc. Although emotionally dramatic, because of its lack of a properly manipulated and isolated Independent Variable and an objectively defined and measured Dependent Variable, no clear cause and effect relationship can be concluded. This study is not a true experiment and does not clearly "prove anything" specific, but rather it can be interpreted and used by anyone as evidence to support many varied points of view.

Prisoner abuse at Abu Ghraib Prison

Zimbardo reflects on the dramatic visual similarities between the behaviour of the participants in the Stanford prison experiment, and the prisoner abuse at Abu Ghraib. He did not accept the Chairman of the Joint Chiefs of Staff General Myers' claim that the events were due to a few rogue soldiers and that it did not reflect on the military. Instead he looked at the situation the soldiers were in and considered the possibility that this situation might have induced the behaviour that they displayed. He began with the assumption that were probably "good apples" in a situation like that of the Stanford prison experiment, where he knew that physically and psychologically normal and healthy people were behaving sadistically and brutalising prisoners.

Zimbardo became absorbed in trying to understand who these people were, asking the question "are they inexplicable, can we not understand them". This is what led him to write the book The Lucifer Effect.

The Lucifer Effect

Zimbardo's book, The Lucifer Effect, gets its title from the metamorphosis of Lucifer into Satan. Though the Christian Scriptures do not make this claim, according to the Biblical account, Lucifer was once God's favorite angel until he challenged God's authority and was cast into Hell with all the other fallen angels. Thus, Zimbardo derives this title to explain how good people turn evil. Zimbardo's main assumption on why good people do terrible things is due to situational influences and power given from authority.

The Lucifer Effect was written in response to his findings in the Stanford Prison Experiment. Zimbardo believes that personality characteristics could play a role in how violent or submissive actions are manifested. In the book, Zimbardo says that humans cannot be defined as good or evil because we have the ability to act as both especially at the hand of the situation. Examples include the events that occurred at the Abu Ghraib Detention Center, in which the defense team—including Gary Myers—argued that it was not the prison guards and interrogators that were at fault for the physical and mental abuse of detainees but the Bush administration policies themselves. According to Zimbardo, "Good people can be induced, seduced, and initiated into behaving in evil ways. They can also be led to act in irrational, stupid, self-destructive, antisocial, and mindless ways when they are immersed in 'total situations' that impact human nature in ways that challenge our sense of the stability and consistency of individual personality, of character, and of morality."

He also notes that we as humans wish to believe in unchanging goodness of people and our power to resist situational and external pressures and temptations. In chapter 12, "Investigating Social Dynamics: Power, Conformity, and Obedience," Zimbardo discusses that peer pressure, the desire to be 'cool,' the fear of rejection, and simply being a part of a group are the focal points to acting preposterous to your character.

In The Journal of the American Medical Association, Zimbardo's situational perspective received support from other social situational experiments that demonstrated the same idea and concept. Almost ten years prior to the Stanford Prison Experiment (1971), Stanley Milgram conducted research on obedient behavior in 1965 that embraced situational forces. Milgram had "teachers" that delivered mock electric shocks to the "learner" for every wrong answer that was given in a multiple choice test. The teachers, however, did not know that the electric shocks were not real, and still delivered them to the learners. At the end of the experiment, 65% of men ages 20–50 complied fully up to the very last voltage. In the same room as the teacher, there was a "confederate" that kept tabs on the teacher and if they were delivering the shocks to each wrong answer. In the beginning of the study, participants signed a waiver that clearly explained the ability to opt out of the experiment and not deliver the shocks. But with the surprising result rate of teachers who did continue to shock the learners, there was a situational force. The situational force that influenced the teachers to continue was the voice of the confederate egging them on by phrases such as, "I advise you to continue with this experiment" or "I am telling you to continue delivering the shocks" and the one that caught most teachers was "You must continue with the shocks." Although the teachers knew that they could leave the experiment at any point in time, they still continued when they felt uncomfortable because of the confederate's voice demanding they proceed.

Both Milgram and Zimbardo's experiment tested situational forces on an individual. Both results concluded that irrational behavior compared to one's character is plausible for any human because we have both tendencies in our nature. Both studies are frequently cited as examples of psychological experiments that were conducted in the mid-20th century that have serious ethical problems involving the treatment of human experimental participants and not clearly explained informed consent. Both studies probably could not receive approval today from any university board of ethics.

There are 7 social processes that grease "the slippery slope of evil":

  • Mindlessly taking the first small step
  • Dehumanization of others
  • De-individuation of self (anonymity)
  • Diffusion of personal responsibility
  • Blind obedience to authority
  • Uncritical conformity to group norms
  • Passive tolerance of evil through inaction or indifference
  • Time

    In 2008, Zimbardo published his work with John Boyd about the Time Perspective Theory and the Zimbardo Time Perspective Inventory (ZTPI) in The Time Paradox: The New Psychology of Time That Will Change Your Life. In 2009, he met Richard Sword and started collaborating to turn the Time Perspective Theory into a clinical therapy, beginning a four-year long pilot study and establishing time perspective therapy. In 2009, Zimbardo did his Ted Talk "The Psychology of Time" about the Time Perspective Theory. According to this Ted Talk, There are six kinds of different Time Perspectives which are Past Positive TP(Time Perspective), Past Negative TP, Present Hedonism TP, Present Fatalism TP, Future Life Goal-Oriented TP and Future Transcendental TP.

    In 2012, Zimbardo, Richard Sword, and his wife Rosemary authored a book called The Time Cure, the same year he presided over the first Time Perspective Conference at Coimbra University, Portugal.

    Time Perspective therapy bears similarities to Pause Button Therapy, developed by psychotherapist Martin Shirran, whom Zimbardo corresponded with and met at the first International Time Perspective Conference at Coimbra University, Portugal. Zimbardo wrote the foreword to the second edition of Shirran's book on the subject.

    Heroic Imagination Project

    Zimbardo is currently heading a movement for everyday heroism as the founder and director of the Heroic Imagination Project (HIP), a non-profit organization dedicated to promoting heroism in everyday life. The project is currently collecting data from former American gang members and individuals with former ties to terrorism for comparison, in an attempt to better understand how individuals change violent behavior. This research portion of the project is co-headed by Rony Berger, Yotam Heineburg, and Leonard Beckum. He published an article contrasting heroism and altruism in 2011 with Zeno Franco and Kathy Blau in the Review of General Psychology.

    Social intensity syndrome (SIS)

    In 2008, Zimbardo began working with Sarah Brunskill and Anthony Ferreras on a new theory called the social intensity syndrome (SIS). SIS is a new term coined to describe and normalize the effects military culture has on the socialization of both active soldiers and veterans. Zimbardo and Brunskill presented the new theory and a preliminary factor analysis of it accompanying survey at the Western Psychological Association in 2013. Brunskill finished the data collection in December 2013. Through an exploratory component factor analysis, confirmatory factor analysis, internal consistency and validity tests demonstrated that SIS was a reliable and valid construct of measuring military socialization. Fifty-eight items were deemed viable and six factors were identified; military friends (16 items), family (11 items), gender social preference (7 items), social bonding (11 items), nostalgia (9 items) and drug use (4 items). Identifying and standardizing SIS was the first step, further research has identified that 4 demographic categories within the military; active and have been deployed (AD), active and never been deployed (AND), inactive and have been deployed (ID) and inactive and never been deployed (IND). These are important categories to better understand how service members are affected leaving the military.

    Other endeavors

    After the prison experiment, Zimbardo decided to look for ways he could use psychology to help people; this led to the founding of The Shyness Clinic in Menlo Park, California, which treats shy behavior in adults and children. Zimbardo's research on shyness resulted in several bestselling books on the topic. Other subjects he has researched include mind control and cultic behavior.

    Zimbardo is the co-author of an introductory Psychology textbook entitled Psychology and Life, which is used in many American undergraduate psychology courses. He also hosted a PBS TV series titled Discovering Psychology which is used in many college telecourses.

    In 2002, Zimbardo was elected president of the American Psychological Association. Under his direction, the organization developed the website, a compendium of psychological research that has applications for everyday life. Also that year, he appeared in the British reality television show, The Human Zoo. Participants were observed inside a controlled setting while Zimbardo and a British psychologist analyzed their behavior.

    In 2004, Zimbardo testified for the defense in the court martial of Sgt. Ivan "Chip" Frederick, a guard at Abu Ghraib prison. He argued that Frederick's sentence should be lessened due to mitigating circumstances, explaining that few individuals can resist the powerful situational pressures of a prison, particularly without proper training and supervision. The judge apparently disregarded Zimbardo's testimony, and gave Frederick the maximum 8-year sentence. Zimbardo drew on the knowledge he gained from his participation in the Frederick case to write a new book entitled, The Lucifer Effect: Understanding How Good People Turn Evil, about the connections between Abu Ghraib and the prison experiments.

    In September 2006, Zimbardo joined the faculty at Palo Alto University as Professor of Psychology, where he teaches social psychology to doctoral students in the clinical psychology program.

    Zimbardo's writing appeared in Greater Good Magazine, published by the Greater Good Science Center of the University of California, Berkeley. Zimbardo's contributions include the interpretation of scientific research into the roots of compassion, altruism, and peaceful human relationships. His most recent article with Greater Good magazine is entitled: "The Banality of Heroism", which examines how ordinary people can become everyday heroes. In February 2010, Zimbardo was a guest presenter at the Science of a Meaningful Life seminar: Goodness, Evil, and Everyday Heroism, along with Greater Good Science Center Executive Director Dacher Keltner.

    Zimbardo, who officially retired in 2003, gave his final "Exploring Human Nature" lecture on March 7, 2007, on the Stanford campus, bringing his teaching career of 50 years to a close. David Spiegel, professor of psychiatry at the Stanford University School of Medicine, called Zimbardo "a legendary teacher", saying that "he has changed the way we think about social influences."

    Zimbardo officially retired from teaching after 57 years, completing his last course at Palo Alto University in March 2014.

    Zimbardo has made appearances on American TV, such as The Daily Show with Jon Stewart on March 29, 2007, The Colbert Report on February 11, 2008 and Dr. Phil on October 25, 2010.

    Zimbardo serves as advisor to the anti-bullying organization Bystander Revolution and appears in the organization's videos to explain the bystander effect and discuss the evil of inaction.

    Since 2003, Phil Zimbardo has been active in charitable and economic work in rural Sicily through the Zimbardo-Luczo Fund with Steve Luczo and the local director Pasquale Marino which provides scholarships for academically gifted students from Corleone and Cammarata.


    In 2016, Zimbardo received an honorary doctorate degree from Charles University in Prague.

    In 2012, Zimbardo received the American Psychological Foundation Gold Medal for Lifetime Achievement in the Science of Psychology.

    In 2005, he received the Dagmar and Václav Havel Foundation Vision 97 Award in Prague.

    In 2003, Zimbardo and University of Rome La Sapienza scholars Gian Vittorio Caprara, and Claudio Barbaranelli were awarded the sarcastic Ig Nobel Award for Psychology for their report "Politicians' Uniquely Simple Personalities".

    Zimbardo was named one of the most influential counseling psychologists alive by Counseling Degrees.


  • Influencing attitude and changing behavior: A basic introduction to relevant methodology, theory, and applications (Topics in social psychology), Addison Wesley, 1969
  • The Cognitive Control of Motivation. Glenview, IL: Scott, Foresman, 1969
  • Stanford prison experiment: A simulation study of the psychology of imprisonment, Philip G. Zimbardo, Inc., 1972
  • Influencing Attitudes and Changing Behavior. Reading, MA: Addison Wesley Publishing Co., 1969, ISBN 0-07-554809-7
  • Canvassing for Peace: A Manual for Volunteers. Ann Arbor, MI: Society for the Psychological Study of Social Issues, 1970, ISBN
  • Influencing Attitudes and Changing Behavior (2nd ed.). Reading, MA: Addison Wesley., 1977, ISBN
  • Shyness: What It Is, What to Do About It, Addison Wesley, 1990, ISBN 0-201-55018-0
  • The Psychology of Attitude Change and Social Influence. New York: McGraw-Hill, 1991, ISBN 0-87722-852-3
  • Psychology (3rd Edition), Reading, MA: Addison Wesley Publishing Co., 1999, ISBN 0-321-03432-5
  • The Shy Child : Overcoming and Preventing Shyness from Infancy to Adulthood, Malor Books, 1999, ISBN 1-883536-21-9
  • Violence Workers: Police Torturers and Murderers Reconstruct Brazilian Atrocities. Berkeley, CA: University of California Press, 2002, ISBN 0-520-23447-2
  • Psychology - Core Concepts, 5/e, Allyn & Bacon Publishing, 2005, ISBN 0-205-47445-4
  • Psychology And Life, 17/e, Allyn & Bacon Publishing, 2005, ISBN 0-205-41799-X
  • The Lucifer Effect: Understanding How Good People Turn Evil, Random House, New York, 2007, ISBN 1-4000-6411-2
  • The Time Paradox: The New Psychology of Time That Will Change Your Life, Simon & Schuster, New York, 2008, ISBN 1-4165-4198-5
  • The Journey from the Bronx to Stanford to Abu Ghraib, pp. 85–104 in "Journeys in Social Psychology: Looking Back to Inspire the Future", edited by Robert Levine, et al., CRC Press, 2008. ISBN 0-8058-6134-3
  • Salvatore Cianciabella (prefazione di Philip Zimbardo, nota introduttiva di Liliana De Curtis). Siamo uomini e caporali. Psicologia della dis-obbedienza. Franco Angeli, 2014. ISBN 978-88-204-9248-9.
  • Man (Dis)connected, Zimbardo, Philip, Coulombe, Nikita D., Rider/ Ebury Publishing, United Kingdom, 2015, ISBN 978-1846044847
  • Maschi in difficoltà. Perché la nuova generazione ha sempre più problemi e come fare per aiutarla (Philip Zimbardo - Nikita Coulombe). Franco Angeli, 2017. ISBN 978-88-917-4406-7. Edizione italiana a cura di Salvatore Cianciabella. Sito:
  • References

    Philip Zimbardo Wikipedia