Back in the day when I worked as a psychologist, I performed psychological evaluations and
taught graduate students how to do the same. I know there is a bunch of fantasy out there about psychological testing and 'putting people in boxes' and such. Let me tell you that testing and evaluations can be individual, specific, and valuable.
Anyhow. The Rorschach Ink Blot Procedure was one of my favorites from early on. It has been the subject of a lot of research, and, if you stick to said research, you can draw reliable conclusions. Now, the Rorschach took off as a clinical instrument (that is, a procedure whose findings can be accurate and useful with troubled people) during WWII. As it happens, the Nuremburg Commission used psychological testing to have some independent measure of who the Nazi war criminals were, to understand better who they were dealing with. At the same time, testing was performed on rank-and-file Nazis in Denmark--self-identified active members of the Danish National Socialist Party who had not committed war crimes, but who had supported and furthered the Nazi activities. The history and outcomes of these assessments are detailed in an excellent book, The Quest for the Nazi Personality: A Psychological Investigation of Nazi War Criminals, whose authors (Eric Zillmer, Molly Harrower, Barry Ritzler, and, Robert Archer) are extraordinarily competent and conscientious. It's a bit technical if you don't have the particular training, but it's a good read.
What were these outcomes? I will summarize. The Danish rank-and-file Nazis differed in some characteristic ways from non-Nazis. For instance, regarding problem-solving, they rarely possessed a dependable approach (e.g., "first things first" or "take the long view" or "practical answers" or "principled above all"). They tended to vacillate inefficiently, with great difficulty solving problems on their own. After such an inauspicious start, they tended to be easily influenced by others and then to adhere rigidly to approaches that had proved unsuccessful, rather than adapting their approach after failure. For all their expressed energy and outcry, they tended to be passive in the face of the actual problem.
Regarding their sense of self and of others, they were more likely to view themselves and others as objects to be manipulated and exploited or feared and hated (or all of these). They were not introspective and were likely to disregard feedback from real relationships--again, disregarding actual events and actual outcomes. Finally--and remember, this is from the Rorschach findings--independent of life events, they were likely to disavow responsibility for their actions and to see themselves as victims.
Does this describe any people you have seen or heard in the last year, interviewed on national television and radio at various rallies? Are you perhaps wondering how so many Americans can have voted for someone whose actions and statements were consistently--supply your preferred adjectives--without concluding that this person's claims were without supporting evidence?
Please understand: I am not calling Trump or his supporters Nazis, except for the ones who call themselves Nazis. I am, however, struck (and discouraged) by certain similarities.