Together, historical evidence and classic psychological studies tell a very powerful story. Decent people can take on oppressive roles and succumb to oppressive leaders. But that does not mean that they always do so. Just as often they resist tyranny. And their resistance tends to be most effective when it is collective.
When one looks closely at the classic studies in social psychology, the same picture emerges.
In Sherif’s studies, the boys fought when divided into groups, but in one study (which was never written up) they refused to be divided and, together, they resisted attempts by the experimenters to set them against each other.
In one (often forgotten) variant of Milgram’s studies, people were much less likely to administer high levels of shock when they had the support of another person who resisted the experimenter.
And in Zimbardo’s study, the Prisoners resisted throughout. When they were isolated they were typically ineffective. But when they worked together as a group their resistance was much more successful. Indeed, at the end of the first day the Prisoners were on top and the Guards were in disarray.