According to Zimbardo's report, one third of the guards were judged to have exhibited "genuine sadistic tendencies", while many prisoners were emotionally traumatized, and three of them had to be removed from the experiment early.
Man fandt at en tredjedel af "vagterne" havde udvist "ægte" sadistiske tendenser, men mange af fangerne blev traumatiseret og fem af dem måtte fjernes fra eksperimentet i utide.