Cognitive dissonance is the uncomfortable feeling that arises when a person holds two conflicting beliefs, or when their behaviour clashes with what they believe. The term was introduced by Leon Festinger in 1957. The discomfort itself is the key point: people generally want their beliefs and actions to fit together, and when they do not, the mismatch feels unpleasant enough that something has to give.
What it looks like
Dissonance often shows up as a small internal argument. A person who values health but smokes may feel uneasy each time they light a cigarette. A person who has just made a difficult choice may suddenly notice all the good points of the option they rejected. The feeling is not always dramatic; often it is a quiet tension, a need to explain something to oneself, or a sudden urge to avoid thinking about the topic altogether.
Why it happens
Festinger’s idea was that inconsistency itself creates psychological discomfort, and people are motivated to reduce it. There are only a few ways out: change the belief, change the behaviour, or add new thoughts that make the conflict seem smaller. The smoker might quit, decide the health risks are exaggerated, or focus on the stress relief smoking provides. Each route reduces the tension, but they are not equally honest or equally helpful. Changing the belief is often easier than changing the behaviour, which is why dissonance can lead to rationalisation as readily as to genuine change. People also avoid information that would increase the conflict, which is why someone may stop reading reviews after an expensive purchase.
An everyday example
Imagine someone buys an expensive phone after weeks of comparing models. Almost immediately, they start noticing reviews that praise a rival phone. The discomfort is dissonance: the belief “I made the best choice” conflicts with the evidence “another phone may be better.” To settle it, they may read glowing reviews of their own phone, tell friends about its best features, or dismiss the rival’s advantages as unimportant. The phone has not changed, but the story around the choice has been adjusted until it feels comfortable again.