Low self-monitors criticize high self-monitors as chameleons and phonies. They’re right that there’s a time and place for authenticity. Some preliminary research suggests that low self-monitors tend to have happier marriages and lower odds of divorce. With your romantic partner, being authentic might lead to a more genuine connection (unless your name is A. J. Jacobs).

But in the rest of our lives, we pay a price for being too authentic. High self-monitors advance faster and earn higher status, in part because they’re more concerned about their reputations. And while that would seem to reward self-promoting frauds, these high self-monitors spend more time finding out what others need and helping them. In a comprehensive analysis of 136 studies of more than 23,000 employees, high self-monitors received significantly higher evaluations and were more likely to be promoted into leadership positions.

Interestingly, women are more likely to be low self-monitors than men, perhaps because women face stronger cultural pressures to express their feelings. Sadly, that puts them at risk for being judged weak or unprofessional. When Cynthia Danaher was promoted to general manager of a group at Hewlett-Packard, she announced to her 5,300 employees that the job was “scary” and that “I need your help.” She was authentic, and her team lost confidence in her initially. Some researchers even suggest that low self-monitoring may have harmful effects on women’s progress.

But even high self-monitors can suffer from the belief in authenticity because it presupposes that there is a true self, a bedrock to our personalities that’s a combination of our convictions and abilities. As the psychologist Carol Dweck has long shown, merely believing that there’s a fixed self can interfere with growth.

Children who see abilities as fixed give up after failure; managers who believe talent is fixed fail to coach their employees. “As we strive to improve our game, a clear and firm sense of self is a compass that helps us navigate choices and progress toward our goals,” Herminia Ibarra, a professor of organizational behavior at the business school Insead, notes. “When we’re looking to change our game, a too rigid self-concept becomes an anchor that keeps us from sailing forth.”

If not our authentic selves, what should we be striving to reach? Decades ago, the literary critic Lionel Trilling gave us an answer that sounds very old-fashioned to our authentic ears: sincerity. Instead of searching for our inner selves and then making a concerted effort to express them, Trilling urged us to start with our outer selves. Pay attention to how we present ourselves to others, and then strive to be the people we claim to be.

Rather than changing from the inside out, you bring the outside in.

When Dr. Ibarra studied consultants and investment bankers, she found that high self-monitors were more likely than their authentic peers to experiment with different leadership styles. They watched senior leaders in the organization, borrowed their language and action, and practiced them until these became second nature. They were not authentic, but they were sincere. It made them more effective.