Final answer:
The overjustification effect example provided is when children are offered payment to play with toys, which can reduce their intrinsic enjoyment of playing, leading to them perceiving it as a task done for extrinsic rewards.
Step-by-step explanation:
An example of the overjustification effect occurs when the introduction of extrinsic incentives, like payment, reduces a person's intrinsic motivation to perform an activity they previously enjoyed. In the scenario provided, children enjoyed playing with toys until they were told they would get paid to play with toys. This is a classic case where extrinsic motivation in the form of monetary reward diminishes the pure enjoyment of an activity. This change in motivation can lead to a perceived obligation to engage in the activity for the reward rather than for the enjoyment it previously provided.