During arrests the police use procedures that lead people to feel confused and fearful. In the case of the Stanford experiment when the prisoners were arrested a process of humiliation began. The twelve undergraduates selected to play the role of prisoners were fingerprinted, mug shots were taken; they were searched, stripped naked, deloused and their heads shaved. Then they were dressed in cheap smocks, with no underwear and had a small chain around one ankle. This process was useful to dehumanize the prisoners, to start making them feel hopeless and turn them into object making them all look the same. Moreover, their names were taken away and they were given identity numbers; the same process used in the Nazi concentration camps.
Even though guards were instructed not to use violence, they started to use authoritarian measures which sometimes lead to torture prisoners too. In particular on the second day of the experiment when the prisoners staged a revolt, once the guards had the prison back under control, they increased the humiliation, aggression and dehumanization. The psychologists had to frequently remind the guards to refrain from such tactics but most of the abuse occurred in the middle of the night when the guards thought the staff members were not watching. Some guards forced prisoners to clean out toilet bowls with their bare hands, act out degrading scenarios, or urged them to become snitches.
I think that the main reason guards were so brutal and evil against the prisoners is not to be attributed to their personal disposition or character but to the role they have. Guards feel powerful like they have the game in their hands so they take advantage of their stronger position compared to the prisoner. After the experiment was stopped prematurely, the psychologists had an encounter session with the participants and people who played the guards role were upset they didn’t get to finish the two weeks experiment. I
References: http://www.prisonexp.org/psychology/1 http://www.experiment-resources.com/stanford-prison-experiment.html http://users.stlcc.edu/rkalfus/PDFs/135c.pdf