When the going gets tough, thousands of people try to boost their failing self-esteem by repeating positive statements to themselves. Encouraged by magazine columnists, self-help books and talk-show hosts, people prepare for challenges by chanting positive mantras like “I am a strong, powerful person,” and, “Nothing can stop me from achieving my dreams.” This approach has been championed at least as far back as Norman Vincent Peale’s infamous book The Power of Positive Thinking, published in 1952.

But a new study suggests that despite its popularity, this particular brand of self-help may backfire badly.  Ironically, it seems to be people with low self-esteem, who are most likely to rely on such statements, who are most likely to feel worse because