Cognitive dissonance or contrast?

Abstract

According to Festinger (1957), cognitive dissonance occurs when one’s behavior or belief is inconsistent with another belief and one modifies one of the beliefs in an attempt to reduce the dissonance. In nonhuman animals, we have examined a version of human cognitive dissonance theory called justification of effort, according to which the value of reward following more difficult tasks increases, presumably to justify (to oneself or to others) performing the more difficult task. We have examined the justification of effort effect in animals and found a pattern similar to the one in humans but we propose a simpler underlying mechanism: contrast between the greater effort and the resulting reward that follows. The contrast model predicts that any relatively aversive event will result in a preference for a reward (or for the signal of a reward) that follows. Much evidence supports this model: Signals for reward are preferred if they are preceded by having to make a greater number of responses, encountering a longer delay, or experiencing the absence of food (when food is presented on other trials). Contrast has also been found when the signals are associated with greater rather than less food restriction. We have also found a shift toward the preference of a food location that requires greater effort to obtain. Analogous effects have been found in humans (both children and adults) using similar procedures.