In times of doubt and uncertainty, many Americans turn to self-help books in search of encouragement, guidance and self-affirmation. The positive self-statements suggested in these books, such as "I am a lovable person" or "I will succeed," are designed to lift a person's low self-esteem and push them into positive action.

According to a recent study in Psychological Science, however, these statements can actually have the opposite effect.

Psychologists Joanne V. Wood and John W. Lee from the University of Waterloo, and W.Q. Elaine Perunovic from the University of New Brunswick, found that individuals with low self-esteem actually felt worse about themselves after repeating positive self-statements.

The researchers asked participants with low self-esteem and high self-esteem to repeat the self-help book phrase "I am a lovable person." The psychologists then measured the participants' moods and their momentary feelings about themselves. As it turned out, the individuals with low self-esteem felt worse after repeating the positive self-statement compared to another low self-esteem group who did not repeat the self-statement. The individuals with high self-esteem felt better after repeating the positive self-statement--but only slightly.

In a follow-up study, the psychologists allowed the participants to list negative self-thoughts along with positive self-thoughts. They found that, paradoxically, low self-esteem participants' moods fared better when they were allowed to have negative thoughts than when they were asked to focus exclusively on affirmative thoughts.

The psychologists suggested that, like overly positive praise, unreasonably positive self-statements, such as "I accept myself completely," can provoke contradictory thoughts in individuals with low self-esteem. Such negative thoughts can overwhelm the positive thoughts. And, if people are instructed to focus exclusively on positive thoughts, they may find negative thoughts to be especially discouraging.

As the authors concluded, "Repeating positive self-statements may benefit certain people [such as individuals with high self-esteem] but backfire for the very people who need them the most."