Our knowledge of individual perpetrators must necessarily rely quite heavily upon testimony drawn from postwar trials. But this has certain difficulties. It is biased toward three of the motives distinguished in the previous chapter: perpetrators said they complied because they were fearful, disciplined, or bureaucratic. Persons accused of war crimes desperately denied having Nazi, racist, anti-Semitic, or murderous intent, claiming, “I was only following orders,” “I was frightened,” “I was only a small cog in a giant machine,” “I was in the motor pool/personnel records/cookhouse all the time.” No one admitted having enjoyed killing; few liked to talk about their SS career achievements. Few incriminated each other or even admitted having had conversations with their colleagues about the genocide cascading around them. From their testimony, this would seem to be an ideology-free environment in which ordinary people were trapped inside coercive and bureaucratic institutions. Yet to accept the self-serving testimony of mass murderers would be unwise.

When motives are so occluded, it is doubtful that we can fully test whether killers might have been of the psychologically disturbed violent type. Court-appointed psychologists did carefully assess a few defendants, usually concluding that they were sane. A court psychologist reported that the Nuremberg defendants' personalities “are not unique or insane … they could be duplicated in any country of the world today.” Most camp survivors report that only a handful of guards were sadists in the sense of being noticeably disturbed individuals.