Earlier quoted context omitted.
I have read studies that too much reward actually destroys the incentive. Instead of doing the work they are supposedly incentivized to do the main focus shifts on getting the reward at any cost.
I think I read that incentives only really work for mundane repetitive work. For anything intellectual or creative it is neutral or even negative.
If my bonus was a multiple of my salary I would probably think more about increasing the bonus at any cost.