“[S]ocial psychologists have begun to study what they call the holier-than-thou effect. They have long known that people tend to be overly optimistic about their own abilities and fortunes — to overestimate their standing in class, their discipline, their sincerity. But this self-inflating bias may be even stronger when it comes to moral judgment … and new research is helping to clarify when such feelings of superiority are helpful and when they are self-defeating.”