An individual's behavior frequently affects the course of events. A person might sell his house, and at some point in the transaction, it may become impossible for him to reacquire the house at any price. A general in the Army may decide to concentrate his defensive forces at point A rather that at point B, and it might take days to reshift his forces should his opponent decide to attack at point B. A candidate for office may publically refer to some people as "Polacks," and this information is spread by the news media so that potential voters become informed of the slur. In each of these cases an individual has behaved in a way that has significance in regard to subsequent events, and it would be difficult for the individual to deny the meaningfulness of his behavior or to change what he had done. These instances in which the cognition about one's own behavior is relatively resistant to change may be called behavioral commitments.
It is behavioral commitment that gives many dissonance reduction processes their irrational tone. Once a person has made a commitment he closes himself off to information that would have led him to alternative types of commitments, and it is this "closedness" in the face of new considerations that leads to the apparent irrationality.
The rational man is one who alters his opinion or behavior in proportion to the evidence implied in each bit of incoming information. He is a computer, or processer, who serves as almost a mathematical link between evidence, evaluation, and behavior. Assuming momentarily that the world can be characterized objectively in terms of whether any particular event is "positive" or "negative" for a specified person, this person will process each incoming piece of information into an overall evaluation of the event. If the price of shaving lotion skyrockets, he will develop an aversion (but a rational aversion) to shaving lotion, if his neighbor shoots his dog he will come to dislike the neighbor, and if the sun should not shine during his visit to Hawaii, Hawaii will fall in his evaluative hierarchy.