Is this what you were looking for? [1] When looking at a financial reward as a motive for great work, a study found this works great for work that is very monotonous/tedious, and horrible for work that requires a lot of thinking. In fact, when offered larger and larger rewards based on better work for the more mentally strenuous work, the quality of work seemed to go down.
[1] https://www.youtube.com/watch?v=u6XAPnuFjJc