We all know the story of the Stanford Prison Experiment. It has been a staple of introductory psychology textbooks and lectures for nearly fifty years (see Griggs, 2014).
Ordinary young men were randomly divided into Prisoners and Guards; within a short time, the Guards become so brutal and the Prisoners so victimised that the study – originally scheduled for two weeks – had to be cut short after only five days.
These findings seem to demonstrate the terrifying power of the situation over individuals. Philip Zimbardo has always insisted that he had to do nothing to produce such toxicity. The participants simply slipped ‘naturally’ – and perhaps unconsciously – into their roles as vicious guards or broken prisoners.
But now, a half century later, dramatic new evidence has emerged that challenges Zimbardo’s account. Our textbooks and our lectures will have to be rewritten. The story of what happened in the SPE and why such brutality occurred will have to be retold.