Stanford Prison Experiment Findings Challenged

There is a strong belief in some circles that if you put ordinary people into bad situations, they can easily be persuaded to do bad things. The most horrific evidence for this probably comes from war. Were the Nazi death camp guards all evil psychopaths? Not very likely. Scientific evidence is rather thin on the ground though.

A series of experiments by Stanley Milgram in the 1960s is very compelling. This is the one where people volunteered to take part in an experiment and were then asked by the experimenter to deliver painful electric shocks to people they didn't know (who were, in fact, stooges of the experimenter who were not really being shocked). The shocks kept increasing in severity to dangerous and harmful levels but around two-thirds of the volunteers went on administering the shocks, despite the apparent victim's screams of pain and pleas to be released. Even when the 'victim' pretended to be unconscious, the volunteers kept on administering the shocks.

A later experiment at Stanford University, by Philip Zimbardo, asked for volunteers for a psychology experiment. The experimenters split the volunteers at random into two groups, giving them the roles of prison guards and prisoners in a mock prison in the university basement. The experiment was planned to last two weeks but was stopped after six days because of the increasingly sadistic behaviour of the guards and the growing trauma of the prisoners.

The Stamford prison experiment is reminiscent of Jane Elliott's 'blue eyes/brown eyes' exercise which she used to do with school kids at about the same time, in the early 1970s, to teach them about prejudice. One day, kids in her class would be told that blue eyes were superior and brown eyes were inferior. On another day, it would be the other way around. She found that kids with the 'superior' eye colour quickly began oppressing those with the 'inferior' eye colour and that kids with the 'inferior' eye colour began to show signs of self-loathing and fear. (Kids are so cute, don't you think?)

Experiments like Milgram's and Zimbardo's are rarely performed these days as university ethics committees try to protect people from the emotional trauma of taking part in such events. Which probably explains why their findings have remained unchallenged for so long. However, an experiment published recently (summarised in the BPS Research Digest) undermines the main conclusion of these classic studies; i.e. that it is the social situation these ordinary volunteers find themselves in that leads to their terrible behaviour.

The experimenters asked for volunteers in the same way that Zimbardo did but they ran two different ads. One asked for male participants for “a psychological study of prison life”; the other invited participants for “a psychological study”. Just three words different. However, instead of doing the Zimbardo study again, they gave their volunteers a load of psychological tests. They found that the people who responded to the “psychological study of prison life” advert scored significantly higher on measures of aggression, authoritarianism, Machiavellianism, social dominance, and lower on measures of altruism and empathy than the people who volunteered for “a psychological study”.

This now leaves open the possibility that the people in Zimbardo's study were self-selected to be sadistic and cruel people – not just ordinary people in a bad situation. By extrapolation to the real world, it may tell us something about people who are involved in atrocities as well as in more minor incidents of oppression, bullying and torment. It may tell us that the people involved in committing such acts of brutality are in a position to harm others because they deliberately put themselves there.

Strangely, I don't find this very reassuring.