What's the difference between Festinger's cognitive dissonance theory and Rogers' incongruity principle? At the core they sound very similar. Is incongruity more relevant to a general view of the self whereas CD more to a specific task?
Mmm... I would say that the main difference between the two is that the ideal self in incongruity is determined by those around you, and the ideal self in cognitive dissonance is determined by you. Because according to Roger, incongruence arises when the love and respect you receive is conditional on you meeting the expectations of others. If you're receiving unconditional positive regard, you won't have incongruence.
Ah, right; and conditional positive regard from parents and conditions of worth (in self-regard) lead to incongruity according to Rogers
and on a sidenote, things like self-serving bias, actor-observer bias, fundamental attribution error, just-world phenomenon and other attributional biases are meant (despite being bad in themselves) to keep you from going too much into cognitive dissonance