Imagine a fearful person who cannot find an adequate cause for his fear. His knowledge, on the one hand, that he is fearful is quite inconsistent with his knowledge, on the other, that there is nothing to fear. Such an inconsistency in knowledge, according to Festinger ( 1957), gives rise to a psychological state which he called "cognitive dissonance." Cognitive dissonance was defined as a motivational state that impells the individual to attempt to reduce and eliminate it. Because dissonance arises from inconsistent knowledge, it can be reduced by decreasing or eliminating the inconsistency. Thus, according to Festinger's analysis, a fearful person who could find nothing to fear is motivated by cognitive dissonance either to reduce his fear or to find some fear-provoking event. Accomplishment of either of these possibilities eliminates the state of cognitive dissonance.
While the example of a fearful person who has nothing to fear contains the central idea of dissonance theory, it omits those aspects of Festinger's ( 1957) theoretical statement that distinguished it from other theories of cognitive balance (e.g., Heider, 1958; Newcomb, 1953). Most notably, the original statement of dissonance theory included propositions about the resistance-to-change of cognitions and about the proportion of cognitions that are dissonant, both of which allowed powerful and innovative analyses of psychological situations. It was the inclusion of these latter propositions that not only distinguished dissonance theory from other theories of cognitive balance, but also made dissonance theory a fertile source of research.
The theory we shall present here is an evolved version of Festinger's ( 1957) original statement. The only significant change from the original has to do with the concept of personal responsibility, to be described later.