Final answer:
Cognitive evaluation theory suggests that extrinsic rewards can often decrease intrinsic motivation, especially when expected, leading to a dependency on extrinsic factors for task engagement.
Step-by-step explanation:
Cognitive evaluation theory posits that the presence of extrinsic rewards can decrease intrinsic motivation. This is because tangible rewards like money can have more negative effects on a person's intrinsic motivation compared to intangible rewards like praise. If an individual expects to receive an extrinsic reward, this expectation can reduce their intrinsic motivation for the task. However, if the extrinsic reward comes as a surprise, the intrinsic motivation is more likely to persist. This phenomenon suggests that while extrinsic rewards can be beneficial in some cases, they may also lead to an overjustification effect where intrinsic motivation is diminished, potentially extinguishing the intrinsic interest in the activity and creating dependency on external rewards for continued performance.