The mental discomfort experienced when holding two or more contradictory beliefs, values, or attitudes, often leading to rationalization or attitude change to reduce the inconsistency.
Drives rationalisation of harmful behaviours, explains attitude changes after commitments, and underlies most self-deception.
The stronger the dissonance, the more motivated people become to resolve it - often by changing their beliefs rather than their behaviour.
"Breaking news: Local human discovers they're not as rational as they thought. Water is wet."