It’s not clear what actually happened during the Stanford Prison Experiment, as the researcher’s observation about the behavior of the guards isn’t corroborated by the participants themselves, while the guards’ accounts of their own behavior might simply be self-serving attempts to clear their names. But Ronson does fixate on the supposedly brutal guard’s explanation that he thought he was doing something good by being brutal to others. This shows that the impulse to do something good—whether that thing is objectively good or simply perceived as good because it’s what someone wants—can be the driving force behind a lot of violent, unacceptable human behavior.