The Lucifer Effect: Understanding How Good People Turn Evil

Prisoner Doug-8612 is the first prisoner arrested for the Stanford Prison Experiment and the first person Zimbardo is forced to release from the experiment due to a mental breakdown. Initially rebellious, Doug quickly loses his grip on reality and demands release. He comes to believe Zimbardo will not release the prisoners in the experiment, and his condition worsens, necessitating his early release.

Guard Hellman is the most brutal, authoritarian, and sadistic guard in the Stanford Prison Experiment. Over the several days of the experiment, he progresses the psychological and physical torture of the prisoners, eventually forcing them to engage in homoerotic acts that could accurately be described as sexual assault. He later states that during the Stanford Prison Experiment, he was performing experiments of his own, to determine how far he could push the prisoners before they pushed back.

Carlo Prescott is an ex-con who has co-taught classes with Zimbardo on prisons and who participates in the Stanford Prison Experiment as the chief parole officer. During the parole hearings, his role reverses, from his former position of the oppressed inmate requesting (and frequently being denied) parole to powerful parole officer, or oppressor, with the authority to grant or deny parole. He is shocked by how easily he embraces his new role as oppressor and wields his power in an authoritarian, over-the-top manner.