Cognitive dissonance is an uncomfortable feeling caused by holding two contradictory ideas simultaneously. The "ideas" or "cognitions" in question may include attitudes and beliefs, the awareness of one’s behavior, and facts. The theory of cognitive dissonance proposes that people have a motivational drive
to reduce dissonance by changing their attitudes, beliefs, and
behaviors, or by justifying or rationalizing their attitudes, beliefs,
and behaviors. Cognitive dissonance theory is one of the most influential and extensively studied theories in social psychology.
Dissonance normally occurs when a person perceives a logical
inconsistency among his or her cognitions. This happens when one idea
implies the opposite of another. For example, a belief in animal rights
could be interpreted as inconsistent with eating meat or wearing fur.
Noticing the contradiction would lead to dissonance, which could be
experienced as anxiety, guilt, shame, anger, embarrassment, stress, and other negative emotional states. When people’s ideas are consistent with each other, they are in a state of harmony, or consonance. If cognitions are unrelated, they are categorized as irrelevant to each other and do not lead to dissonance.
A powerful cause of dissonance is an idea in conflict with a fundamental element of the self-concept,
such as "I am a good person" or "I made the right decision." The
anxiety that comes with the possibility of having made a bad decision
can lead to rationalization,
the tendency to create additional reasons or justifications to support
one’s choices. A person who just spent too much money on a new car
might decide that the new vehicle is much less likely to break down
than his or her old car. This belief may or may not be true, but it
would likely reduce dissonance and make the person feel better.
Dissonance can also lead to confirmation bias, the denial of disconfirming evidence, and other ego defense mechanisms.