What is the phenomenon of cognitive dissonance?

Cognitive dissonance refers to the psychological discomfort that arises when a person holds two or more contradictory beliefs, values, or attitudes at the same time, or when their behavior conflicts with their beliefs. This state of dissonance creates an uncomfortable tension, prompting individuals to either change their beliefs, modify their behaviors, or find some justification to reduce the inconsistency.

For example, if someone values health and fitness but frequently consumes junk food, they experience cognitive dissonance because their behavior contradicts their beliefs about healthy living. To alleviate this discomfort, they might either change their eating habits or rationalize that they exercise enough to offset the junk food. The underlying principle is that humans seek harmony among their thoughts and behaviors, and when that harmony is disrupted, the psychological response often motivates change to restore balance.