ARRA: Effect of Prior Event on Reward Value

We will investigate in pigeons a phenomenon, cognitive dissonance, that when studied in humans has been called the justification of effort. Specifically, greater value is attributed to rewards that have required greater effort to obtain (Aronson & Mills, 1959). This effect has been attributed to the need to resolve dissonance engendered by the exertion of greater effort to obtain comparable rewards. However, we have found that pigeons will reliably prefer stimuli associated with food if those stimuli are preceded by a high effort response over those preceded by a low effort response. We have interpreted the effect as a form of contrast in which the larger change in value that follows greater effort is preferred over the smaller change in value that follows less effort. We propose: (1) To examine two noncognitive accounts of this effect The first, a within-trial contrast effect that occurs upon the presentation of the conditioned stimulus associated with reinforcement (5+) following the greater effort. The second is delay reduction theory which is based on the degree to which the conditioned stimulus signals reinforcement better than its absence. In three experiments, we will equate the trial duration (time between reinforcements) to eliminate differential delay reduction and determine which equal- time schedule is preferred and then determine which 5+ that follows is preferred. (2) To determine if experience with rich or lean schedules prior to or during training will modi~' the within-trial contrast effect Rich schedules enhance the contrast, lean schedules should diminish it