Quote from "Basic Psychology", Henry Gleitman, Norton 1983 "Cognitive Consistency"
... people try to make sense of the world they encounter. But how? In effect,they do this by looking for some consistency among their own experiences and memories, and turning to other people for comparison and confirmation. If all checks out, then all well and good. But what if there is some inconsistency? The Asch study (Solomon Asch, 1956) showed what happened when there is a serious inconsistency between one's own experiences (and the beliefs based on them) and those reported by others. But suppose the inconsistency is among the person's own experiences, beliefs or actions? Many social psychologists believe that this will trigger some general trend to restore cognitive consistency - to reinterpret the situation so as to minimize whatever inconsistency may be there. According to Leon Festinger, this is because any perceived inconsistency among various aspects of knowledge, feelings and behavior sets up an unpleasant internal state - cognitive dissonance - which people try to reduce whenever possible (Festinger, 1957).
Cognitive dissonance is not always reduced so easily. An example is provided by a study of a sect that was awaiting the end of the world. The founder of the sect announced that she had received a messsage from the "Guardians" of outer space. On a certain day, there would be an enormous flood. Only the true believers were to be saved and would be picked up at midnight of the appointed day in flying saucers. (Technology has advanced onsiderably since the days of Noah's Ark.) On doomsday, the members of the sect huddled together, awaiting the predicted cataclysm. The arrival time of the flying saucers came and went; tension mounted as the hours went by. Finally, the leader of the sect received another message: To reward the faith of the faithful, the world was saved. Joy broke out and he believers became more faithful than ever. (Festinger, Riecken and chachter, 1956)
Given the failure of a clear-cut prophecy, one might have expected the very opposite. A disconfirmation of a predicted event should presumably lead one to abandon the beliefs that produced the prediction. But cognitive dissonance theory says otherwise. By abandoning the beliefs that there are Guardians, the person who had once held this belief would have to accept a painful dissonance between her present skepticism and her past beliefs and actions. Her prior faith would now appear extemely foolish. Some members of the sect had gone to such lengths as giving up their jobs or spending their savings; such acts would lose all meaning in retrospect without the belief in the Guardians. Under the new circumstances, the dissonance was intolerable. It was reduced by a belief in the new message which bolstered the original belief. Since other members of the sect stood fast long with them, their conviction was stengthened all the more. They could now think of themselves, not as fools, but as loyal, steadfast members of a courageous little band whose faith had saved the earth.