Dan Pink on the surprising science of motivation

What is the right incentive for people to perform?
Reward and performance only work for automated (easy, dummy ) tasks. It is because the problem is already easy, extrinsic reward can help narrow their focus on the problem.

Intrinsic motivation is good for creative, hard problem. Reward with money in this case will lower the performance. It is because the solution for this sort of problem is wide. Outside reward (or pressure) will stop the free mind.

Most of the real business problems are not easy, so high bonus is usually the not solution.

http://www.ted.com/talks/dan_pink_on_motivation.html