Advancing from novice to amateur can break the rethinking cycle. As we gain experience, we lose some of our humility. We take pride in making rapid progress, which promotes a false sense of mastery. That jump-starts an overconfidence cycle, preventing us from doubting what we know and being curious about what we don’t. We get trapped in a beginner’s bubble of flawed assumptions, where we’re ignorant of our own ignorance.

That’s what happened in Iceland to Davíe Oddsson, whose arrogance was reinforced by cronies and unchecked by critics. He was known to surround himself with “fiercely loyal henchmen” from school and bridge matches, and to keep a checklist of friends and enemies. Months before the meltdown, Oddsson refused help from England’s central bank. Then, at the height of the crisis, he brashly declared in public that he had no intention of covering the debts of Iceland’s banks. Two years later an independent truth commission appointed by Parliament charged him with gross negligence. Oddsson’s downfall, according to one journalist who chronicled Iceland’s financial collapse, was “arrogance, his absolute conviction that he knew what was best for the island.”

What he lacked is a crucial nutrient for the mind: humility. The antidote to getting stuck on Mount Stupid is taking a regular dose of it. “Arrogance is ignorance plus conviction,” blogger Tim Urban explains. “While humility is a permeable filter that absorbs life experience and converts it into knowledge and wisdom, arrogance is a rubber shield that life experience simply bounces off of.”

WHAT GOLDILOCKS GOT WRONG

Many people picture confidence as a seesaw. Gain too much confidence, and we tip toward arrogance. Lose too much confidence, and we become meek. This is our fear with humility: that we’ll end up having a low opinion of ourselves. We want to keep the seesaw balanced, so we go into Goldilocks mode and look for the amount of confidence that’s just right. Recently, though, I learned that this is the wrong approach.

Humility is often misunderstood. It’s not a matter of having low self-confidence. One of the Latin roots of humility means “from the earth.” It’s about being grounded—recognizing that we’re flawed and fallible.

Confidence is a measure of how much you believe in yourself. Evidence shows that’s distinct from how much you believe in your methods. You can be confident in your ability to achieve a goal in the future while maintaining the humility to question whether you have the right tools in the present. That’s the sweet spot of confidence.

We become blinded by arrogance when we’re utterly convinced of our strengths and our strategies. We get paralyzed by doubt when we lack conviction in both. We can be consumed by an inferiority complex when we know the right method but feel uncertain about our ability to execute it. What we want to attain is confident humility: having faith in our capability while appreciating that we may not have the right solution or even be addressing the right problem. That gives us enough doubt to reexamine our old knowledge and enough confidence to pursue new insights.

When Spanx founder Sara Blakely had the idea for footless pantyhose, she believed in her ability to make the idea a reality, but she was full of doubt about her current tools. Her day job was selling fax machines door-to-door, and she was aware that she didn’t know anything about fashion, retail, or manufacturing. When she was designing the prototype, she spent a week driving around to hosiery mills to ask them for help. When she couldn’t afford a law firm to apply for a patent, she read a book on the topic and filled out the application herself. Her doubt wasn’t debilitating—she was confident she could overcome the challenges in front of her. Her confidence wasn’t in her existing knowledge—it was in her capacity to learn.

Confident humility can be taught. In one experiment, when students read a short article about the benefits of admitting what we don’t know rather than being certain about it, their odds of seeking extra help in an area of weakness spiked from 65 to 85 percent. They were also more likely to explore opposing political views to try to learn from the other side.

Confident humility doesn’t just open our minds to rethinking—it improves the quality of our rethinking. In college and graduate school, students who are willing to revise their beliefs get higher grades than their peers. In high school, students who admit when they don’t know something are rated by teachers as learning more effectively and by peers as contributing more to their teams. At the end of the academic year, they have significantly higher math grades than their more self-assured peers. Instead of just assuming they’ve mastered the material, they quiz themselves to test their understanding.

When adults have the confidence to acknowledge what they don’t know, they pay more attention to how strong evidence is and spend more time reading material that contradicts their opinions. In rigorous studies of leadership effectiveness across the United States and China, the most productive and innovative teams aren’t run by leaders who are confident or humble. The most effective leaders score high in both confidence and humility. Although they have faith in their strengths, they’re also keenly aware of their weaknesses. They know they need to recognize and transcend their limits if they want to push the limits of greatness.

If we care about accuracy, we can’t afford to have blind spots. To get an accurate picture of our knowledge and skills, it can help to assess ourselves like scientists looking through a microscope. But one of my newly formed beliefs is that we’re sometimes better off underestimating ourselves.

THE BENEFITS OF DOUBT

Just a month and a half before Iceland’s presidential election, Halla Tómasdóttir was polling at only 1 percent support. To focus on the most promising candidates, the network airing the first televised debate announced that they wouldn’t feature anyone with less than 2.5 percent of the vote. On the day of the debate, Halla ended up barely squeaking through. Over the following month her popularity skyrocketed. She wasn’t just a viable candidate; she was in the final four.

A few years later, when I invited her to speak to my class, Halla mentioned that the psychological fuel that propelled her meteoric rise was none other than impostor syndrome. Feeling like an impostor is typically viewed as a bad thing, and for good reason—a chronic sense of being unworthy can breed misery, crush motivation, and hold us back from pursuing our ambitions.

From time to time, though, a less crippling sense of doubt waltzes into many of our minds. Some surveys suggest that more than half the people you know have felt like impostors at some point in their careers. It’s thought to be especially common among women and marginalized groups. Strangely, it also seems to be particularly pronounced among high achievers.

I’ve taught students who earned patents before they could drink and became chess masters before they could drive, but these same individuals still wrestle with insecurity and constantly question their abilities. The standard explanation for their accomplishments is that they succeed in spite of their doubts, but what if their success is actually driven in part by those doubts?

To find out, Basima Tewfik—then a doctoral student at Wharton, now an MIT professor—recruited a group of medical students who were preparing to begin their clinical rotations. She had them interact for more than half an hour with actors who had been trained to play the role of patients presenting symptoms of various diseases. Basima observed how the medical students treated the patients—and also tracked whether they made the right diagnoses.

A week earlier the students had answered a survey about how often they entertained impostor thoughts like I am not as qualified as others think I am and People important to me think I am more capable than I think I am. Those who self-identified as impostors didn’t do any worse in their diagnoses, and they did significantly better when it came to bedside manner—they were rated as more empathetic, respectful, and professional, as well as more effective in asking questions and sharing information. In another study, Basima found a similar pattern with investment professionals: the more often they felt like impostors, the higher their performance reviews from their supervisors four months later.

This evidence is new, and we still have a lot to learn about when impostor syndrome is beneficial versus when it’s detrimental. Still, it leaves me wondering if we’ve been misjudging impostor syndrome by seeing it solely as a disorder.