The science of evil: ‘bad barrels’ or ‘bad apples’ at Abu Ghraib?

When the shocking photos of American soldiers abusing Iraqi prisoners at Abu Ghraib hit the news in February 2006, some attributed the heinous acts to “a few bad apples” on the night shift. But a “bad barrel,” not “bad apples,” caused ordinary Americans to do repugnant things, said social psychologist Philip Zimbardo, an emeritus professor at Stanford University. Based on what psychological research had revealed about evil (which Zimbardo defined as “intentionally behaving in ways that harm, abuse, demean, dehumanize or destroy innocent others-or using one’s authority or systemic power to encourage or permit others to do so on your behalf”), the excesses at Abu Ghraib were not only unsurprising but entirely predictable, he said.


The issue was brought into fresh focus in September 2007 when an Army officer was acquitted of failing to properly supervise soldiers who abused prisoners at Abu Ghraib. Eleven soldiers were convicted in the scandal, but Lt. Col. Steven L. Jordan was the only officer to stand trial on charges related to the abuses. He was found guilty of a lesser offense, disobeying an order to refrain from discussing the case.

Zimbardo’s book, The Lucifer Effect: Understanding How Good People Turn Evil, draws a compelling parallel between abuse at Abu Ghraib and during the Stanford Prison Experiment, a famous 1971 simulation study headed by Zimbardo that randomly assigned ordinary American college students to portray either guards or prisoners in a mock prison located in a campus building. Within days “guards” began treating “inmates” with sadistic cruelty-much like the abuse visited on the inmates of Abu Ghraib-that forced Zimbardo to end the project, originally planned to run for two weeks, a week early. Psychological tests administered before the experiment had revealed no mental problems among the students, nor any differences among those assigned as guards or prisoners. Rather, the situational factors and social dynamics within the fake prison released the capacity for evil inherent in all human beings, leading to behavior ordinarily considered abhorrent, Zimbardo said. This, he maintained, also happened at Abu Ghraib.

Zimbardo called the transformation of normal individuals into perpetrators of evil against powerless victims the “Lucifer Effect.” after the fallen angel who changes from God’s favorite into Satan. Zimbardo used this Christian image metaphorically. Many Christians, however, take a different view of evil from Zimbardo’s, believing it to have an existence as a distinct entity. Some believe in Satan’s literal existence and ability to influence human beings. In this view, evil actions arise out of the evil inherent in individual “bad apples.”

Zimbardo, however, did not consider evil as a metaphysical or spiritual entity but rather as a category of behavior arising largely from psychological and social forces. He rejected the view that evil behavior necessarily arises from the inner qualities of individual perpetrators. Instead, he took a situational view of evil behavior, ascribing it in large measure to outer forces and circumstances that allow or encourage actions that would ordinarily violate individuals’ views of appropriate behavior. He did not absolve individuals of moral responsibility for performing these actions, but he argued that the leaders of systems and institutions-including the Spanish Inquisition, the Nazi state, the Stanford Prison Experiment and Abu Ghraib prison-bear great culpability for creating the social forces and situations that allow or encourage ordinary people to tolerate, condone and even perpetrate evil acts that in other circumstances would be entirely foreign to their experience.

Despite the apparently pessimistic finding of the Stanford Prison Experiment that ordinary people can, in the right-or, more accurately, the wrong-circumstances behave in evil ways, for Zimbardo the situational perspective also leads to an optimistic conclusion: that a “good barrel” can induce ordinary people to behave generously, courageously, even heroically, for the benefit of others and that situational circumstances and social dynamics created by properly designed systems and institutions can foster and encourage such behavior. Human nature contains the possibility of both evil and good, he said, and with proper training, people can learn to resist the influences that lead to evil actions and will respond to influences and situations that call on them to act altruistically and courageously.

If situational and systemic factors rather than the inherent qualities of individuals are largely responsible for determining whether individuals or groups do evil or good, then responsibility for the behavior of people within systems and organization in large measure rests with those who design, lead and administer them. According to this view, the source of wrongdoing therefore cannot be sought only in the depravity or weakness of individuals or in the separate essence or force of evil. Nor can guilt be ascribed solely to the immediate perpetrators of evil actions. According to this view, the solution to the problem of evil action lies not only in correcting the behavior of individuals but in redesigning systems. Leadership at all levels must therefore be held to account for the behavior throughout organizations. In cases such as the Stanford Prison Experiment and Abu Ghraib, for example, Zimbardo apportioned a large measure of blame to the leaders (himself included) who designed abusive systems, established their rules, and provided inadequate supervision to the individuals who ultimately carried out evil acts. This conception of evil shifts attention away from the inherent qualities of individuals or the actions to Satan to the analysis of systems and institutions.

Why it matters

The social psychologists’ view that “bad barrels” are often to blame for individual actions challenges people’s perceptions – as well as theological concepts of evil. In an era of when scandals are not uncommon in government, military, corporate and religious institutions, this view also raises questions about who should be held responsible and what changes need to take place to prevent future scandals and crimes.


National sources

  • Philip Zimbardo

    Philip Zimbardo, Stanford University professor emeritus of psychology, is the author of The Lucifer Effect: Understanding How Good People Turn Evil. He was director of the Stanford Prison Experiment.

  • Guy B. Adams

    Guy B. Adams is professor of public affairs in the Harry S Truman School of Public Affairs and an affiliated faculty member of the Center on Religion & the Professions at the University of Missouri in Columbia. He is co-author of the award-winning book Unmasking Administrative Evil.

  • Roy F. Baumeister

    Roy F. Baumeister is a professor and Francis Eppes Eminent Scholar in Social Psychology at Florida State University in Tallahassee. He is the author of Evil: Inside Human Violence and Cruelty.

  • David Blumenthal

    David Blumenthal is a professor of Judaic studies at the Tam Institute of Jewish Studies at Emory University in Atlanta. He is the author of two seminal books on Jewish mysticism, God at the Center: Meditations on Jewish Spirituality and Understanding Jewish Mysticism. Additionally, he is the author of The Banality of Good and Evil: Moral Lessons from the Shoah and Jewish Tradition. He notes that both perpetrators and rescuers often say they were just doing what was expected of them.

  • Steven Miles

    Dr. Steven Miles is a professor of medicine and bioethics at the University of Minnesota’s Medical School and Center for Bioethics in Minneapolis, and he is a past president of the American Society of Bioethics and Humanities. He is an author of the original “do not resuscitate” order and has been active in state and national health-care reform. His books include The Hippocratic Oath and the Ethics of Medicine (Oxford University Press, 2004) and Oath Betrayed: Military Medicine and the War on Terror (Random House, July 2006). He has also published 30 chapters and 100 peer-reviewed articles on medical ethics, human rights, tropical medicine, end-of-life care and geriatric health care. He served on President Clinton’s Bioethics Working Group on Health Care Reform. Miles’ work changed tuberculosis treatment for refugees and end-of-life care and has led to the reduction of restraints in nursing homes. His international work includes 25 years of work with the American Refugee Committee.

  • James E. Waller

    James E. Waller is the Cohen Chair of Holocaust and Genocide Studies at Keene State College in New Hampshire and author of Becoming Evil: How Ordinary People Commit Genocide and Mass Killing (Oxford University Press, 2002).

    Contact: 603-358-2490.
  • Ervin Staub

    Ervin Staub is professor emeritus of psychology at the University of Massachusetts in Amherst and founding director emeritus of its doctoral program on the psychology of peace and the prevention of violence. He has written several books about evil, including The Psychology of Good and Evil: Why Children, Adults and Groups Help and Harm Others and Overcoming Evil: Genocide, Violent Conflict and Terrorism (2010).

  • Danny L. Balfour

    Danny L. Balfour is a professor and past director of the School of Public and Nonprofit Administration at Grand Valley State University in Grand Rapids, Mich. He is co-author of Unmasking Administrative Evil and of “Abu Ghraib, Administrative Evil, and Moral Inversion: The Value of ‘Putting Cruelty First’ ” in the September/October 2006 issue of Public Administration Review.

  • Martha K. Huggins

    Martha K. Huggins is Charles A. and Leo M. Favrot Professor of Human Relations at Tulane University in New Orleans and co-author of Violence Workers: Police Torturers and Murderers Reconstruct Brazilian Atrocities.

  • Arthur G. Miller

    Arthur G. Miller is a psychology professor at Miami University in Oxford, Ohio, and editor of The Social Psychology of Good and Evil.

  • Herbert Kelman

    Herbert Kelman is Richard Clarke Cabot Professor of Social Ethics, Emeritus, in the psychology department at Harvard University in Cambridge, Mass., and co-author of Crimes of Obedience: Toward a Social Psychology of Authority and Responsibility.

Regional sources

In the Northeast

  • Jack Levin

    Jack Levin, professor of sociology and criminology and co-director of the Brudnick Center on Violence and Conflictat Northeastern University in Boston, has written about domestic terrorism, hate crimes, youth violence, ethnic conflict and mass and serial murder.

  • John F. Dovidio

    John F. Dovidio is a psychology professor at the Yale University. He is a social psychologist and co-author of the chapter “Contemporary Racial Bias: When Good People Do Bad things” in The Social Psychology of Good and Evil.

  • Samuel L. Gaertner

    Samuel L. Gaertner is a psychology professor at the University of Delaware in Newark. He is a social psychologist and co-author of the chapter “Contemporary Racial Bias: When Good People Do Bad Things” in The Social Psychology of Good and Evil.

  • Susan Fiske

    Susan Fiske is a psychology professor at Princeton University and co-author of a 2004 Science magazine article, “Policy Forum: Why ordinary people torture enemy prisoners.”

  • Barbara Kellerman

    Barbara Kellerman is the James McGregor Burns Lecturer in the Leadership at the Center for Public Leadership of the Kennedy School of Government at Harvard University and the author of Bad Leadership: What It Is, How It Happens, Why It Matters.

In the South

  • Jerome Rosenberg

    Jerome Rosenberg, University of Alabama psychology professor, teaches courses on the Holocaust that examine the dark side of human behavior and the nature of good and evil.

  • John Donelson Ross Forsyth

    John Donelson Ross Forsyth holds the Colonel Leo K. and Gaylee Thorsness Chair in Ethical Leadership at the Jepson School of Leadership Studies of the University of Richmond and teaches a course in the psychology of good and evil.

  • June Tangney

    June Tangney is a psychology professor at George Mason University near Washington, D.C., who has studied how individual traits and situations contribute to forgiveness.


  • Sung Hee Kim

    Sung Hee Kim is an associate professor of psychology and a member of the social psychology core group at the University of Kentucky in Lexington. Her research interests include conflict, group processes and vengeance.

  • Nicholas Carnagey

    Nicholas Carnagey is visiting professor of psychology at Wake Forest University in Winston-Salem, N.C., and co-author of the chapter “Violent Evil and the General Aggression Model” in The Social Psychology of Good and Evil.

In the Midwest

  • Dan Batson

    Dan Batson is a professor emeritus of psychology at the University of Kansas in Lawrence. He has studied empathy as a possible source of altruistic motivation and the psychological implications of the egoism-altruism relationship. He has also researched other sources of positive social motivation, such as collectivism and principalism. He wrote The Altruism Question: Toward a Social-Psychological Answer (Erlbaum, 1991) and “Addressing the Altruism Question Experimentally” in Altruism and Altruistic Love (Oxford University Press, 2002).

  • Arlin J. Benjamin Jr.

    Arlin J. Benjamin Jr. is a social psychologist at University of Arkansas-Fort Smith. In his research, he applies social psychological theories of aggression to help understand how torture and genocide happen. He is the author of “Human aggression and violence: Understanding torture from a psychological perspective,” published in National Social Science Journal in 2006.

  • Craig Anderson

    Craig Anderson is a psychology professor at Iowa State University in Ames and co-author of “Violent Evil and the General Aggression Model” in The Social Psychology of Good and Evil. 

In the West

  • Adam Cohen

    Adam Cohen is an assistant professor of social psychology at Arizona State University in Tempe. His interests include moral judgment.

  • Elliot Aronson

    Elliot Aronson is emeritus professor of psychology at University of California, Santa Cruz, and author of Nobody Left to Hate: Teaching Compassion After Columbine. 

    Contact: 831-459-5084.
  • Jack Glaser

    Jack Glaser is a social psychologist and assistant professor of public policy at the Goldman School of Public Policy at the University of California-Berkeley. He studies the social psychology of hate crimes and intergroup violence.

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