Now imagine you discover that your co-worker, when at home, regularly fails to do any of these things. He is a hypocrite. You promptly revoke the moral credit you gave him for his activism. In fact, his hypocrisy now makes his activism seem not just not-positive, but negative: How dare he go around telling other people to switch off their lights when he doesn’t do so himself!

This dislike of hypocrisy is emotionally intuitive, but if you pause to think about it, it constitutes a psychological puzzle. If you believe it’s important to protect the environment, shouldn’t you be glad your co-worker is promoting the right values (even if he himself is wasteful)? Logically speaking, there is nothing dishonest about condemning an action and also engaging in it. So why does criticizing something make it seem worse to do it oneself?

Our contention is that your objection to your co-worker is perfectly logical, because the principal offense of a hypocrite is not that he violates his own principles, but rather that his use of moral proclamations falsely implies that he himself behaves morally.

This idea makes sense if you think about moral condemnation not as a tool for reproaching others but as a way to boost your own reputation. In one set of studies, we found support for this view: People tended to take someone’s normative statements — such as “It is morally wrong to waste energy” — as an indication of how the speaker himself acted. In fact, our findings show that people would be more likely to believe that the speaker did not waste energy if he said, “It is wrong to waste energy,” than if he simply said, “I do not waste energy.” Moral condemnation seems to act as a particularly powerful signal of behavior — more powerful than even direct statements about behavior.

Once you understand moral criticism this way, you can see why people feel deceived by hypocrites. In another set of studies, we found that people viewed hypocrites as dishonest — more dishonest, in fact, than people who uttered outright falsehoods. Remarkably, hypocrites were rated as less trustworthy, less likable and less morally upright than those who openly lied: e.g., characters who wasted energy after explicitly stating that they never wasted energy.