It is a happy faculty of the mind to slough that which conscience refuses to assimilate. ~ William Faulkner
Cognitive dissonance is mental stress from simultaneously holding contradictory ideas, values, or beliefs. In 1957, American social psychologist Leon Festinger noted that the mind strives for consistency (the principle of cognitive consistency).
The mind mitigates cognitive dissonance in 3 possible ways: 1) change belief or behavior, 2) justify the dissonance through rationalization, or 3) deny or ignore information that creates dissonance, and, for good measure, avoid information and situations likely to augment the dissonance.
For instance, a man wanting to diet to lose weight falls prey to a jelly donut. To crack the dissonance between behavior and intent, he may: 1) stop eating the donut, 2) justify its consumption: by rationalization (need energy now), allowing latitude (cheating just this once), or compensation (promising to exercise it off later), or 3) deny the conflict (this donut is not especially fattening).
Decisions often arouse dissonance by bringing to the fore conflicting priorities and goals. Dissonance is reduced by augmenting the attractiveness of one alternative while degrading another.
Sometimes dissonance is created externally. Forced compliance is being compelled by someone to do something distasteful. The decision to submit is rationalized to reduce internal dissonance.
Cognitive dissonance sometimes soothes over an otherwise troubled psyche. People value most achievements or goods which required considerable effort or outlay to obtain. Rather than denigrate pursuit for something of low value, the tendency is to consider the effort worthwhile, even if only paying for one’s education.
Denial also works. If something turns out badly, convincing oneself that it was as good as circumstances permitted dismisses dissonance.