Zimbardo misrepresents his Prison Experiment as "controlled". It had neither internal nor external validity and there was no control group whatsoever. He continues to promote a position which has been contradicted both empirically and theoretically. Recently, a group of psychologists released a public letter to alert people that his claims are not supported. He was directly responsible for the abuse that took place in that experiment and which caused the mental breakdown of two of the students. A film he produced from the experiment was used by the military in torture training.