When you walk through the self-help aisle of any bookstore, you are likely to see plenty of books based on the notion that positive thinking is the key to getting what you want. The message is clear: if you want to achieve something, just keep telling yourself “I can!” and envision yourself accomplishing your goals. Success will surely come your way.
Not so, says years of psychological research. Certain kinds of positive thoughts, known in the research as fantasies, can actually be detrimental to performance.