Psychopaths—whose ranks swell with remorseless cold-blooded killers—are notorious for their lack of empathy, and they typically have smaller than normal amygdalae and insulae, along with other areas involved in the processing of emotion. Psychopaths are also less bothered than most people by foul odors, feces, and bodily fluids, tolerating them—as one scientific article put it—“with equanimity.”
