Cognitive consistency

In the field of psychology, cognitive dissonance is the mental discomfort (psychological stress) experienced by a person who simultaneously holds two or more contradictory beliefs, ideas, or values. The occurrence of cognitive dissonance is a consequence of a person's performing an action that contradicts personal beliefs, ideals, and values; and also occurs when confronted with new information that contradicts said beliefs, ideals, and values.

In A Theory of Cognitive Dissonance (1957), Leon Festinger proposed that human beings strive for internal psychological consistency in order to mentally function in the real world. That a person who experiences internal inconsistency tends to become psychologically uncomfortable, and so is motivated to reduce the cognitive dissonance: either by changing parts of the cognition, to justify the stressful behavior; or by adding new parts to the cognition that causes the psychological dissonance; and by actively avoiding social situations and contradictory information that are likely to increase the magnitude of the cognitive dissonance.

To function in the reality of a modern society, human beings continually adjust the correspondence of their mental attitudes and personal actions; such continual adjustments, between cognition and action, result in one of three relationships with reality:

The reduction of the psychological stress of cognitive dissonance is a function of the magnitude of the dissonance caused by the existential inconsistency between two contradictory beliefs held by the person, or the contradiction between the person's beliefs and an action taken and realised by him or her. Two factors determine the degree of psychological dissonance caused by two conflicting cognitions or by two conflicting actions:

Cognitive dissonance theory proposes that people seek psychological consistency between their personal expectations of life and the existential reality of life. To function by that expectation of existential consistency, people practice the process of dissonance reduction in order to continually align their cognitions (perceptions of the world) with their actions in the real world.

The creation and establishment of psychological consistency allows the person afflicted with cognitive dissonance to lessen his or her mental stress by actions that reduce the magnitude of the dissonance, realised either by changing with, or by justifying against, or by being indifferent to the existential contradiction that is inducing the mental stress. In practice, people reduce the magnitude of their cognitive dissonance in four ways:

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