Philip Zimbardo obituary: psychologist behind the Stanford Prison ...

One quiet Sunday morning in August 1971, police swept through Palo Alto, California, arresting male students for armed robbery and burglary. They were spreadeagled against police cars, searched and handcuffed, often with bemused neighbours watching on.

At the station they were fingerprinted, photographed and blindfolded. Taken one at a time to “Stanford County Jail”, they were stripped naked and deloused with a spray, a procedure designed in part to cause humiliation. They were then issued with prison uniforms and numbers. Instead of having their heads shaved, they were given a nylon cap to cover their hair.

Their guards, who were dressed in khaki uniforms and wearing sunglasses to deter eye contact, were given no specific training. However, they were warned that the prisoners might be