In 1978, Dr. Pauline Rose Clance described a pattern of fear she found among people who secretly believe they have climbed too high and will be found out at any moment. She called it "the impostor phenomenon."
It was, she wrote, a neurosis that exists in perfectionists who can never live up to their own high standards. Some men suffer from it, of course. But it reminds me of just about every woman I know, from the high-powered lawyer and lobbyist to the mom every other mother admires. Women don't believe their accomplishments are real or deserved.
All these years later, women earn more college and graduate degrees than men, they make up half the workforce, and a woman may very well be our next president. But, like the stubborn gap in wages between men and women, which has not budged in almost 30 years, this confidence gap continues, too.
Journalists Katty Kay of the BBC and Claire Shipman of ABC News, who have interviewed many accomplished women and are pretty accomplished themselves, have rediscovered the impostor phenomenon and have written anew about its causes and consequences in their book, "The Confidence Code: The Science and Art of Self-Assurance — What Women Should Know."
Apart from the compromises often required of motherhood and the cultural and institutional barriers that still exist, the authors say, women suffer from an acute lack of confidence, choosing to ignore or discount the evidence of their own achievements.
Ms. Kay, for example, continues to believe she is only asked to be on all those television news panels because her British accent makes her sound smart. Ms. Shipman became CNN's Moscow correspondent in her 20s but tells people she was just in the right place at the right time.
Science and their own experiences interviewing powerful women illustrate this confidence gap, the authors said. Women don't seek promotions until they are sure they have 100 percent of the skills necessary, a level of competence men don't require of themselves when they go after a new job. Men initiate salary negotiations four times more often than women do, and they ask for 30 percent more money.
The authors quoted research that found that men regularly overestimate their abilities and performance and that women regularly underestimate theirs. But, when examined, their performances do not differ substantially.
It isn't that men are trying to fool anybody. And they have their moments of doubt, too. But men don't let those doubts stop them, and their "honest overconfidence" actually propels them ahead if for no other reason than those around them tend to believe it, too.
Girls learn early to work hard and to behave. Boys are encouraged to take risks. And while hard work and good behavior help girls succeed in school, it is the willingness to take risks and to make mistakes that helps boys succeed in the workplace. It is that risk-taking and perseverance through failure that builds confidence in men. That doesn't happen for women who concentrate on following the rules.
"Confidence is the stuff that turns thoughts into action," Ohio State psychology professor Richard Petty told the authors. Action may also require courage, persistence, anger and creativity in some cases. But action always requires confidence.
Sometimes women, despite a reticence that is both cultural and biological, just need to act. To get out of their own heads, decide and then do.
This book has drawn criticism from some feminist corners because it seems to put the onus squarely on a woman's shoulders. If she doesn't succeed, it is because she dithered, it is because she couldn't find the guts.
There is no doubt that sexism continues to exist in business and culture. Much of it has just gone underground and is less visibly offensive. It is a battle women will fight for generations to come.
In the meantime, for our daughters' sake and for our own, we need to use the discipline we apply to so many areas of our work and family life and silence the small voice inside that keeps telling us we are not worthy.