Question

Why is money a demotivator?​

Answer 1

Because “people given a financial incentive were now less interested in solving puzzles on their own time.”

Answer 2

For: Money is an effective, powerful and simple motivator. Self-evidently, money motivates and extra money motivates people to work extra hard. It's natural to compete, and when rewarded with money for better work then productivity and standards are raised for all..

While money often doesn't motivate, it can nonetheless be a powerful demotivator. In “Blocked employees and money as a motivator,” James daSilva notes that too little money can be especially demotivating to top-performing employees who are “blocked” from earning more.