The Stanford Prison Experiment (SPE) is widely recognized as one of the most ethically controversial psychology studies ever conducted. In 1971, 24 college students who had volunteered to take part in a “psychological study of prison life” were randomly assigned to roles as guards and prisoners within a “prison” that had been specially constructed in the basement of the Stanford University psychology department. As most psychology students would be aware, the study had to be brought to a premature close after six days due to the intense distress that the prisoners were experiencing at the hand of the guards. At the time, the ethical framework for conducting research of this form was poorly defined and relatively informal. But partly as a consequence of the horrors it led to, after the SPE, psychologists’ code of research ethics was formalized and tightened, with the result that many felt it would never again be possible to conduct studies of this form.

Despite – or perhaps because of – this, since it was conducted, the SPE has exerted a vice-like grip over discussions about the issues of tyranny and evil that it investigated. This means that when reflecting on large-scale human atrocity, it is commonplace for researchers and commentators alike to reprise the argument that this reflects people’s “natural” tendency to conform uncritically to the specifications of any group roles they are assigned, however noxious they might be. This in itself is of major ethical concern, potentially letting perpetrators off the hook. Thus, if conducting studies like the SPE raises serious ethical issues, not conducting them is equally of ethical concern.