Affect and the overjustification effect.

The Overjustification effect describes a phenomenon whereby a person who performs an intrinsically interesting activity for an expected, external reward sometimes decreases his or her subsequent interest and engagement in that activity. In contrast to the previous literature's emphasis on cognitive factors, the present research focuses on the role of affect as a mediator of the Overjustification effect. Specifically it was proposed that negative affect has a critical detrimental influence on intrinsic motivation, either as a reaction derived from self-perception and evaluation processes or as a factor that acts independently of these cognitive activities. Two studies using the typical Overjustification paradigm were undertaken to test these hypotheses. In Experiment 1, the Overjustification effect was successfully replicated for both behavioral and self-report measures of intrinsic motivation. It is important that the negative affect paralleled these results and was greatest in those conditions in which intrinsic motivation was predicted and found to be low (e.g., expected reward). In Experiment 2, affect was directly manipulated, independently of the cognitive manipulations. The results showed that the induced positive affect erased the decrease in intrinsic motivation that was observed in Experiment 1. It is suggested that what determines the decrease in intrinsic interest in any activity is, in part, the amount of negative affect that becomes associated with the activity.