What happens during the free-choice period? Evidence of a polarizing effect of extrinsic rewards on intrinsic motivation

The "undermining effect" [e.g., Deci, E. L., Koestner, R., & Ryan, R. M. (1999) A meta-analytic review of experiments examining the effects of extrinsic rewards on intrinsic motivation, Psychological Bulletin, 125(6) 627-668], whereby extrinsic rewards decrease intrinsic motivation, is typically tested using the free-choice paradigm. The arbitrary length of the free-choice period, however, might obscure the process of undermining. We used a foreshortened free-choice period - immediately and after 1 week - to glimpse the process of undermining with 61 college students who engaged in an intrinsically interesting activity under a reward or no-reward condition. Analyses revealed a polarizing effect of extrinsic rewards on intrinsic motivation for the immediate and delayed assessments. We consider this effect in relation to the process of undermining, and suggest a potential personality-based moderator of the effect. (C) 2009 Elsevier Inc. All rights reserved.