Gamification: Rewards can … demotivate
Researchers found that extrinsic motivation can step in front of intrinsic motivation and that can be a problem to engagement in gamification projects because people will start to do things focusing on the reward itself and not because they just enjoy to do it (intrinsic motivators).
The drawing experiment: A group of kids were on a experiment, they gave paper and pencil to them and asked them to draw.
Some of the kids drew great pictures and they were really involved in doing so. After this the researchers started to offer rewards in exchange to the drawings and they noticed that the quality of drawings became lower but the amount increased. After that the researchers removed the rewards and then the kids simply stopped drawing: they substituted the intrinsic motivator for the extrinsic motivator. This is called Overjustification Effect.
Depending on the reward type, this Overjustification Effect can be soften if the reward is unexpected. People tend to not put extrinsic motivations in front of their intrinsic motivations if they don’t know that the activity will be rewarded with something.