Pre-and post-choice change of preference as a function of number and similarity of alternatives

Festinger's cognitive dissonance theory (1957) concerns the conditions under which attitudes and opinions are changed. The powerfulness of the theory is its simplicity by which imponderably complicated social situation could be relatively easily handled. The demonstration of the phenomenon and its derivatives have been carried out so many times since 1957. But some investigators (Chapanis and Chapanis, 1964) questioned the operational adequacy of the phenomenon, the nature of dissonance, the discarding of experimental subjects etc., and concluded that cognitive dissonance is not a reliable psychological phenomenon. The present experiment is an attempt to clarify some confusions of experiment done by J. W. Brehem and A. R. Cohen (1959) who intended to demonstrate the two derivates of cognitive dissonance theory applied to choice situation: (1) other things being equal, the greater the number of alternatives, the greater the magnitude of dissonance created by the choice, (2) other things being equal the greater the dissimilarity of alternatives, the greater the dissonance produced by choice.