Final answer:
The enjoyment of an activity itself is intrinsic motivation, deriving from internal satisfaction, while being paid for an action, such as mowing a lawn for money, is an example of extrinsic motivation. Research suggests that excessive extrinsic rewards can lead to the overjustification effect, which diminishes intrinsic motivation.
Step-by-step explanation:
When we talk about the enjoyment of an activity itself, we are referring to intrinsic motivation, which arises from internal factors and is driven by an interest or enjoyment in the task itself. This contrasts with extrinsic motivation, where external factors like money, fame, or grades drive one's behaviors. The question regarding Carl mowing the lawn for $20 exemplifies extrinsic motivation, as the activity is driven by the external reward of receiving money, rather than the pleasure of the task itself (Choice A: extrinsic).
According to research mentioned by Deci and colleagues, extrinsic rewards can sometimes undermine intrinsic motivation, leading to a phenomenon known as the overjustification effect. This indicates that if a person who loves a hobby begins to receive extrinsic rewards for it, they may begin to perceive it as work and lose that initial intrinsic interest. However, other studies indicate that extrinsic reinforcements such as verbal praise may actually bolster intrinsic motivation, showing the complexity of human motivational structures.