Intrinsic motivation and norms about payment, Journal of Personality
Several previous studies have shown that rewarding individuals for preforming an interesting task may have an inhibitory effect on tast satisfaction and persistence. In this experiment, an extrinsic reward decreased task satisfaction and persistence when a norm for no payment existed, but the inhibitory effect was not found when a norm for payment was associated with the task. This result is discussed in terms of the "means-ends" theoretical perspective developed by Calder and Straw (1975b) as well as other dcompeting explanations.
Calder, Bobby. 1979. Intrinsic motivation and norms about payment. Journal of Personality. 48(1): 1-14.