Overjustification Effect - Controversy

Controversy

The overjustification effect is controversial because it challenges previous findings in psychology on the general effectiveness of reinforcement on increasing behavior, and also the widespread practice of using incentives in the classroom. In fact, a 2001 meta-analysis showed that rewards can increase intrinsic motivation for tasks that initially hold little intrinsic interest. Nevertheless, two meta-analyses found that, for high-interest tasks, intrinsic motivation is diminished by expected, tangible rewards in both children and adults, especially when the reward is given for simply performing a task, regardless of the results. Nontangible rewards, such as verbal praise, and unexpected rewards do not undermine intrinsic motivation. In fact, praise may actually increase intrinsic motivation, as long as the praise is interpreted as sincere and a valid signal about the actor's competence.

These conclusions were challenged in a separate meta-analysis which found that tangible rewards offered for outperforming others and for performing uninteresting tasks (in which intrinsic motivation is low) lead to increased intrinsic motivation, and stated that the detrimental effects of rewards on motivation only occur in a specific, restricted set of conditions that could be easily avoided. This set of analyses included both high-interest and low-interest tasks, whereas the original meta-analyses conducted by Deci and colleagues (1999) restricted analyses to tasks in which participants initially had high interest.

A rebuttal defended the original findings, concluding that this analysis by Cameron (2001) was flawed and that Cameron's inclusion of boring tasks in analyzing potential overjustification effects made little theoretical or practical sense. This rebuttal argued that cognitive evaluation theory is the most consistent structure for explaining the effects of rewards on intrinsic motivation, pointing to several other papers that have supported the theory.