The article "Motivation Crowding Theory: A Survey of Empirical Evidence" examines how external rewards can affect people's intrinsic motivation. The researchers reviewed various studies and found that offering rewards for tasks that are inherently interesting can actually decrease motivation. This is because external rewards can undermine individuals' natural desire to engage in an activity for its own sake. The findings suggest that intrinsic motivation is important for maintaining interest and enjoyment in tasks, and that external rewards should be used carefully to avoid crowding out this internal drive.