In psychology, cognitive dissonance is an uncomfortable feeling or stress caused by holding two contradictory ideas simultaneously. The theory of cognitive dissonance proposes that people have a fundamental cognitive drive to reduce this dissonance by modifying an existing belief, or rejecting one of the contradictory ideas.
Often one of the ideas is a fundamental element of ego, like "I am a good person" or "I made the right decision." This can result in rationalization when a person is presented with evidence of a bad choice, or in other cases. Prevention of cognitive dissonance may also contribute to confirmation bias or denial of discomforting evidence.
Experiments have attempted to quantify this cognitive drive. Studies have not so far detected any gender or cross-cultural differences.
Cognitions which contradict are said to be "dissonant," while cognitions which agree with each other are said to be "consonant." Cognitions which neither agree nor disagree with each other are said to be "irrelevant." (Festinger, 1957). "Cognitions" include knowledge, attitude, emotion (known as ambivalence), belief, or behavior.
The introduction of a new cognition that is dissonant with a currently held cognition creates a state of "dissonance," the magnitude of which relates to the relative importance of the involved cognitions. Dissonance can be reduced either by eliminating dissonant cognitions, or by adding new consonant cognitions. The maximum possible dissonance is equal to the resistance to change of the less "resistant cognition"; therefore, once dissonance reaches a level that overcomes the resistance of one of the cognitions involved, that cognition will be changed or eliminated, and dissonance will be reduced.
This leads some people who feel dissonance to seek information that will reduce dissonance and avoid information that will increase dissonance. People who are involuntarily exposed to information that increases dissonance are likely to discount that information, either by ignoring it, misinterpreting it, or denying it.
Festinger however, acknowledged the powerful impact of central, self-relevant cognitions. He did imply that in spite of the strong drive to seek consistency between cognitions and behavior, there may be situations where the original cognitions are so central to the person's self-concept that they may be resistant to change towards greater consistency. Indeed, several scientists in the literature have shown how individuals who are provided with performance feedback that is discrepant from original beliefs about the self will tend to strengthen their original beliefs and attitudes further through other behaviors when given the opportunity to do so (BDG, 2007).
More recently, Tedeschi has argued that maintaining cognitive consistency is a way to protect public self-image (Tedeschi, Schlenker & Bonoma, 1971). From 1965, Daryl Bem (1965; 1967) has proposed self-perception theory as an alternative to cognitive dissonance theory. This states that people do not have inner access to their own attitudes - let alone whether they are in conflict. Bem interpreted people in the Festinger and Carlsmith study as inferring their attitudes from their behaviour. Thus, when asked "Did you find that task interesting?" they would judge that, as they told someone they did, they must have done. This self-perception theory was based largely on the behaviorism of B.F. Skinner. Bem interprets those paid twenty dollars in the Festinger and Carlsmith study as being able to interpret their vocal behaviour as an example of what behaviorists such as Skinner call "mands" - that is, elements of speech that are commands and demands rather than mere statements. Consequently, these people would have not seen their vocal behaviour as an utterance describing their behaviour.
In many experimental situations, Bem's theory and Festinger's theory make similar predictions, and so it has been very difficult for experimental social psychologists to design a conclusive experiment that will provide more evidence for one rather than the other of these two theories. However, advocates of dissonance theory sometimes argue that of these two theories, only Festinger's theory predicts that certain processes in social cognition will increase arousal, although there is some dispute about how much Festinger's original theory really did imply that cognitive dissonance increased arousal. Therefore, from 1970 onwards, some psychologists have investigated whether being faced with situations where one's cognitions are likely to conflict, arousal is likely to increase, and have found experimental evidence that this is the case.
In April 2008, economist M. Keith Chen suggested that experiments used to verify cognitive dissonance could be flawed. He cited the problem of the effect of choice removal on the statistical analysis (the Monty Hall problem).
However, the experimenter then asked the subject for a small favor. He was told that a needed research assistant was not able to make it to the experiment, and the participant was asked to fill in and try to persuade another subject (who was actually a confederate) that the dull, boring tasks the subject had just completed were actually interesting and engaging. Some participants were paid $20 for the favor, another group was paid $1, and a control group was not requested to perform the favor.
When asked to rate the peg-turning tasks later, those in the $1 group rated them more positively than those in the $20 group and control group. This was explained by Festinger and Carlsmith as evidence for cognitive dissonance. Experimenters theorized that people experienced dissonance between the conflicting cognitions "I told someone that the task was interesting", and "I actually found it boring". When paid only $1, students were forced to internalize the attitude they were induced to express, because they had no other justification. Those in the $20 condition, it is argued, had an obvious external justification for their behavior, and thus experienced less dissonance. Behavior internalization is only one way to explain the subject's ratings of the task. The research has since been extended. It is now believed that there is a conflict between the belief that "I am not a liar", and the recognition that "I lied".
The experimenters concluded that many human beings, when persuaded to lie without being given sufficient justification, will carry out the task by convincing themselves of the falsehood, rather than telling a bald lie.
This study has been criticized, on the grounds that being paid twenty dollars may have aroused the suspicion of some participants. In subsequent experiments, two common alternative methods of "inducing dissonance" were used. In one, experimenters used counter-attitudinal essay-writing, in which people were paid varying amounts of money (e.g., one or ten dollars) for writing essays expressing opinions contrary to their own. The other method was to ask subjects to rate a number of different objects according to their desirability. The subject is then offered a choice between two objects s/he had rated equally, with the knowledge that choosing any one of the two would mean "missing out" on the possible positive features of the unchosen object, thus inducing dissonance.
The experimenter would question the child on a set of toys to gauge which toys the children liked the most and which they found the least tempting. The experimenter then chose a toy that the child really liked, put them in a room with it, and left the room. Upon leaving the room the experimenter told half the children that there would be a severe punishment if they played with the toy and told the other half that there would be a moderate punishment.
Later, when the punishment, whether severe or moderate, was removed, the children in the moderate punishment condition were less likely to play with the toy, even though now it had no repercussion.
When questioned, the children in the moderate condition expressed less interest in the toy than would be expected towards a toy that they had initially ranked high in interest. Alternatively, the desirability of the toy went up for the children in the severe punishment condition.
This study laid out the effect of over-justification and insufficient justification on cognition.
In over-justification, the personal beliefs and attitudes of the person do not change because they have a good external reason for their actions. The children threatened with the severe punishment had a good external reasoning for not playing with the toy because they knew that they would be badly punished for it. However, they still wanted the toy, so once the punishment was removed they were more likely to play with it. Conversely, the children who would get the moderate punishment displayed insufficient justification because they had to justify to themselves why they did not want to play with the toy since the external motivator, the degree of punishment, was not strong enough by itself. As a result, they convinced themselves that the toy was not worth playing with, which is why even when the punishment was removed they still did not play with the toy.