Are Intrinsic and Extrinsic Rewards Additive: A Test of Deci's Cognitive Theory of Task Motivation.

Expectancy theory and reinforcement theory of task motivation have assumed that the effects of extrinsic and intrinsic reinforcement are additive in nature. Deci (1971, 1972a, 1972b, 1972c) has recently presented tentative evidence which reportedly shows that contingent monetary rewards actually reduced intrinsic task motivation. This paper reexamines the evidence presented by Deci and then tests his cognitive evaluation theory explanation in both a boring and non-boring task setting. The evidence presented here, along with a reexamination of Deci's previous findings, indicates that contingent monetary payments, which are not delayed, have an additive effect with intrinsic rewards on task motivation. The results are discussed in relation to their implication to management.