Cognitive dissonance is described as psychological discomfort that arises from holding incompatible ideas at the same time. The theory of cognitive dissonance was developed in 1957 by Leon Festinger (1919 to 1989), an American psychologist, and has at its core the principle that people strive to maintain consistency among pairs of cognitions or "knowledges" about their own opinions and behaviors and about the surrounding world. According to the theory inconsistency, or dissonance, between cognitions creates psychological uneasiness, which stimulates people to mitigate the dissonance and make the cognitions fit together.
A commonly cited example of cognitive dissonance is smoking, where the knowledge that smoking is dangerous to health is in conflict with the individual's enjoyment of smoking. In order to tackle the dissonance a smoker might change one of the cognitions, such as his behavior, and give up the habit. Or he might dilute the inconsistency by playing down the negative effects of smoking.
Sometimes, people's actions contradict their beliefs, in which case they have to deal with dissonant cognitions. An action, because it has already been completed, cannot be changed, so the individual has to try to reduce the dissonance by changing their attitude in order to justify their behavior. This phenomenon is termed the insufficient-justification effect, and refers to a change in one's attitude undertaken because there is no other way in which a past action can be justified. Induced compliance, a situation where people defend an attitude that clashes with their own opinions, is probably the most studied experimental situation of dissonance. In Festinger and Carlsmith's original experiment, participants were required to perform a boring task. Some of them were then asked to do a favor and persuade other people that the task was enjoyable. Some were paid $1 in exchange for the favor and others were offered $20. There was also a third, control group, that was not asked to do the favor.
At the end of the experiment, participants were asked to rate the task and the results showed that those who were paid $1 had a more positive attitude towards the task than those who received $20 and those in the control group. Festinger and Carlsmith interpreted this as evidence for cognitive dissonance. They argued that participants felt dissonance between the thoughts of finding the task boring and lying that it was interesting. Those who received the higher payment had an external justification for their action and so endured less dissonance. Having no such justification, however, participants in the other group acted to resolve the dissonance by internalizing the opinion they were forced to express.
The theory has identified several different types of dissonance. One is post-decision dissonance. It arises after a person has made a decision and is prompted by the possibility of it not being the right one. People often respond by altering their perceptions in order to justify the decision. A form of post-decision dissonance is buyer's remorse after the purchase of a high-cost product.
Another type of dissonance is forced compliance dissonance, which arises when people are compelled to adopt behavior not consistent with their beliefs. People also experience dissonance when faced with new information that questions or alters their beliefs as well as in different group situations. An example of the latter is when they must scrap old beliefs or embrace new beliefs to become part of a group.
Dissonance theory has changed over time. It was found that the original theory, though praised for its simplicity, did not explain all of the phenomena observed in experiments. Consequently, a number of revisions have been proposed. For example, in 1969, Aronson linked the theory to the self-concept. In his view, cognitive dissonance is not prompted by a conflict between cognitions but by a conflict between people's actions and their typically positive images of themselves.
In the 1980s, Cooper and Fazio proposed that the reason for dissonance was not inconsistency but negative consequences. Thus, according to their model, people experience tension not because of conflicting cognitions but because lying, for instance, is wrong. Subsequently, research showed that people feel dissonance when the consequences of their behavior are not adverse as well.