From what I heard (based on recent research perhaps?) when it's about ability, you should praise what the kid does and not what they are, but when it's about morality, you should praise what they are, not what they do. If they're being good, that is. If they see themselves as a good person, they're more likely to be good. But if they see themselves as smart, they're less likely to work to accomplish anything, because it should be easy for them.