I am watching an online course on gamification. It mentioned explicit motivation and implicit motivation and described interesting examples of over-justification effect that subjects can be demotivated by rewards. The first one is about drawing by kids. Many kids are very interested in drawing and are inherently motivated to draw. However, when they are given rewards for their drawings, their intrinsic interests are replaced by the extrinsic rewards. When their rewards are removed, some of them do not enjoy drawing anymore and no longer find it fun. I guess this also happens to artists and even scientists. They may be interested in their work genuinely at first. But when their monetary interests are too closely tied to their perceived performance (number of records sold, number of papers written, number of proposals funded), they start to be demotivated since their intrinsic interests are replaced by extrinsic motivation.
I find the second following example even more revealing. A day care school in Israel found that many parents didn’t pick up their kids on time. Therefore, they decide to penalize parents by imposing a small fine if a parent is more than 10 minutes late. They thought that the punishment will incentivize a parent to arrive on time. But the result is that more parents are late and those are late even arrive later. Basically, parents have intrinsic motivation to not to be late in the past from social pressures such as not to make a nuisance to other parents or the day care staff. But when a punishment is imposed, the intrinsic motivation is replaced with an extrinsic motivation and they no longer feel qualm to be late as they feel that their actions are justified by the fine they paid.
In any case, the over-justification effect is a very refreshing idea to me. It may not be new to many of you. But as an engineer, I have never thought that rewards can demotivate before.