What induces professors to sign letters of support for their colleagues who are under attack? I was under public attack a few years back, and although few actual faculty members attacked me (the Chancellor being an exception, while chairing a faculty senate meeting and sitting fifteen feet away from me), none publicly supported me either, and I sensed an atmosphere of fear of public opinion. A couple of recent cases provide interesting data. Roughly speaking, at Missouri faculty from the humanities supported a colleague under attack, and at Yale faculty from the sciences did, both with a few exceptions from other fields. What is interesting is that of the 116 Missouri signers, 84 were from humanities departments and just 4 were from science departments, while of the 90 Yale signers, 41 were from science departments and 6 from the humanities (all from language or music departments). I excluded psychology from science, but added math and computer science, and did the best I could for Yale to decide which professors in the medical school were scientists.
Missouri had 0 signers from economics, 0 from the business school and 1 from law. Yale had 3 from economics, 11 from the business school, and 1 from law. The Missouri professor was in communications and journalism (5 signers) and the Yale professors were in psychology and sociology (18 signers).