What makes a hero? Dr. Philip Zimbardo, the psychologist behind the infamous Stanford Prison Experiment, now runs seminars to teach everyday people how to be heroes. But can heroism be learned? I put his unsuspecting students into a fake crisis situation to see if they would act heroically. Also, I asked employees to help me run a seemingly dangerous experiment, to see if they would blow the whistle to stop me.

Normal people can become monsters, given the right situation. That’s the standard narrative of the Stanford Prison Experiment, one of the most famous psychological experiments of all time. But what if the cause of its participants’ cruel behavior wasn’t what we’ve always been told?