Phillip Zimbardo had long been curious as to why prisons were such violent places, and he wanted to find out whether it’s due to the character of its inhabitants or due to the corrosive effect of the power structure within the prison walls.
He created a mock experiment at the Stanford psychology department by recruiting young men with no criminal records and assigned half of them to play as guards while the other half played as prisoners.
Social conditions deteriorated instantly with the prisoners staging a revolt on the first night, causing the guards to resort to ‘creative’ methods to discipline the prisoners. Prisoners began to crack because of these and even Zimbardo was drawn to the corrosive psychology of the situation when he began to have paranoid fears that the prisoners were planning to attack him, prompting him to call the police for help.
In six days, he turned happy college kids into brooding prisoners and brutal guards and was forced to call off the experiment.