…if your objective is to get long-term quality in the workplace, to help students become careful thinkers and self-directed learners, or to support children in developing good values, then rewards, like punishments, are absolutely useless.  In fact, as we are beginning to see, they are worse than useless – they are actually counterproductive.

-Alfie Kohn, from Punished by Rewards: The Trouble with Gold Stars, Incentive Plans, A’s, Praise, and Other Bribes