We tend to assess morality in other people on a digital scale. A person can be trusted or can't, with perhaps one or two “I'm not too sure about that guy” gradations in between. This is very different from expertise and authority, which we gauge in small increments—the president carries more weight than the vice president who counts more than his aide; a general is above a colonel is above a sergeant; and so on. Also, when it comes to gauging the trustworthiness of other people we envision morality as a stable and consistent personality predisposition, one that varies little across time or situations. In fact, honesty and trustworthiness, like all personality traits, are highly dependent on the situation. As early as 1928, for example, researchers demonstrated that whether a child cheated in one situation was a poor predictor of whether he'd cheat in an even slightly different one. Some cheated on multiple choice tests but not on essays; others were just the opposite…
Nonetheless, because moral trustworthiness is perceived as relatively unwavering, a little of it goes a long way. Once a reputation is established, it grows legs of its own. This is particularly true for negative reputations. If you're labeled as untrustworthy, good luck in reversing the appraisal. Almost anything you do, no matter how well-meaning, will be read as dishonest manipulation or shameless ingratiation. To some extent, a parallel process works to sustain positive reputations. We usually want to believe that the person we've labeled as trustworthy will continue to meet our expectations. Life is easier that way. And so, once the halo is attached, we do our best to ignore and explain away indiscretions that might compromise our impression. However, a good reputation is less durable than a bad one. Studies show that it requires many more good behaviors to alter a bad image than it does bad behaviors to alter a good image. Then again, studies also show that it takes fewer bad behaviors to establish a bad reputation in the first place. In other words, good reputations are difficult to acquire but easy to lose. Bad reputations are easy to acquire and difficult to lose...
The Power of Persuasion: How We're Bought and Sold - Robert V. Levine
https://www.amazon.com/Power-Persuasion-Were-Bought-Sold/dp/0471763179
