Research reviewed by the Northwest Regional Educational Laboratory gives parents and teachers guidance on this subject. Praise is the most commonly used reward or reinforcer in the classroom. It turns out that not all praise is created equal. In the language of praise a whisper speaks louder than a shout. You are one of the few who understands what research is all about.
Effective praise is specific and informative.
Teachers who are careful with giving praise are more effective than those who gush over a correct answer. Praise encourages learning when it is sincere and believable. Some people feel strongly that giving rewards, particularly material ones, sends a message to children that learning is not worthwhile in and of itself. Another criticism of rewards is that they undermine inner motivation and that any learning benefits of rewards will evaporate when the reward is no longer given. Research on such questions is inconclusive but it appears that rewards may have negative effects under certain conditions, such as when they are very large or are given without a clear connection to academic performance.