In 1971, a Stanford University team of researchers led by psychology professor Philip Zimbardo and funded by the US Navy and Marine Corps set up a famous experiment into the causes of conflict between military guards and prisoners. Some 24 male students were selected to take on arbitrary roles as prisoners and guards in a mock prison in the basement of the Stanford psychology building. The experiment tragically went well beyond Zimbardo’s expectations, with the “guards” increasing the pressure on the prisoners to the point where the prisoners were subjected to psychological torture – and the “prisoners” accepted the abuse, readily harassing other prisoners who attempted to prevent it. The entire experiment was abruptly stopped after only six days because of its horrific implications.