Philip Zimbardo, who has died aged 91, was a psychologist whose studies included work on shyness, the psychological roots of evil and the effects of the past on decision-making; but he was best known for the 1971 Stanford Prison Experiment,

Psychologist behind controversial ‘Stanford Prison Experiment’ dies at 91 - The study was ended after six days as the students playing guards became psychologically abusive

Philip Zimbardo's 1971 Stanford University experiment, employing college students to play prison guards and inmates, became one of the most controversial episodes in modern psychology.

Zimbardo's 'Prison Experiment,' a landmark and controversial study, was shut down after six days, but its implications have had a profound effect.

Dr Zimbardo is remembered for an ill-fated 1971 prison study in which he recruited college-aged males to spend two weeks in a mock prison in the basement of a building on the Stanford campus.

Philip G Zimbardo, the psychologist behind the controversial Stanford Prison Experiment which was intended to examine the psychological experiences of imprisonment, has died at the age of 91. Stanford University announced that he died on October 14 at his home in San Francisco. A cause of death was not provided.

Philip Zimbardo, the psychologist behind the controversial "Stanford Prison Experiment" in which participants playing prison guards became abusive, has died aged 91. Stanford University announced his death on Friday,

The 1971 prison study was scheduled for two weeks, but was stopped after six days when college-aged students playing guards became psychologically abusive.

The 1971 prison study was scheduled for two weeks, but was stopped after six days when college-aged students playing guards became psychologically abusive and those playing prisoners became anxious, emotionally depressed,