Generic overjustification: The interaction of extrinsic rewards

Abstract

An experiment was conducted to test the hypothesis that the value of one extrinsic reward will be undermined when another extrinsic reward is made contingent upon the same activity. Subjects were assigned to one of three experimental groups. Some were paid a contingent monetary reward for engaging in a monotonous and boring activity and were then given the opportunity to continue to work voluntarily for additional payment. Others were given both money and extra experimental credit for the required task, and were likewise offered additional pay for voluntary extra work. A third group of subjects received money for the required task, but were given no additional rewards for extra work. It was observed that the money + credit subjects did less extra work for pay than the money-only subjects. They also rated the monetary reward as having been of less value to them. Subjects who were paid during the initial task session but not for extra work did less additional work than those who were paid in both sessions, but did not differ in their ratings of the value of the monetary reward. It is concluded that extrinsic rewards are nonadditive, and that current models of undermined rewards are too limited to account for this phenomenon. A selective attention hypothesis is advanced as an alternative.