But beliefs are themselves gritty and persistent. Duckworth cites surveys supporting this point. Ask Americans which they think is more important to success, effort or talent, and they pick effort two to one. Ask them which quality they’d desire most in a new employee, and they pick industriousness over intelligence five to one. But deep down, they hold the opposite view.

We know this thanks to another researcher, whose work Duckworth draws on, Chia-Jung Tsay of University College London. Tsay asked professional musicians to listen to audio clips of two pianists, one described as a “natural,” the other as a “striver.” Despite the fact that the two pianists were really one pianist playing different sections of the same composition—and in flat contradiction to the listeners’ stated belief that effort trumped talent—the musicians thought the “natural” sounded more likely to succeed than the “striver,” and more hirable. Tsay found a similar prejudice among people considering an investment proposal. Their preference for backing a “natural” entrepreneur over a “striver” entrepreneur was erased only when the latter was given four more years of experience and $40,000 more in capital.

Whence the bias for naturals? Duck-worth offered me her best guess: We don’t like strivers because they invite self-comparisons. If what separates, say, Roger Federer from you and me is nothing but the number of hours spent at “deliberate practice”—as the most-extreme behavioralists argue—our enjoyment of the U.S. Open could be interrupted by the thought There but for the grace of grit go I.

Whatever its origins, the bias has practical implications. Certainly, it suggests that my deep terror of letting anyone see my half-written article drafts is not irrational but adaptive. It perpetuates a myth that I’m a natural—the words just flow out, folks, as fast as I can type!—and hides the far more mundane truth: that the words come out fitfully and woodenly, gradually succumbing to a state of readability only after many seemingly fruitless sessions. “If people knew how hard I had to work to gain my mastery, it would not seem so wonderful at all,” Michelangelo observed. Nietzsche concurred: “Wherever one can see the act of becoming one grows somewhat cool.”

Which suggests that Duckworth’s basic admonition, “Embrace challenge,” needs a qualifier: Do it in private. Grit may be essential. But it is not attractive.

This can make for confusing career advice. “Try hard enough and you can do just about anything, as long as you don’t seem to be trying very hard” is not the stuff of school murals. Yet the combination of private toil and public ease, Duckworth agreed, may well be the beau idéal between countervailing imperatives.

Still, the prevalence of hidden practice among successful people is costly to society because it obscures the amount of failure that goes into success. Go on YouTube, Duckworth suggests in her book, and try to find footage of “effortful, mistake-ridden, repetitive deliberate practice.” I did, and took her point. You cannot watch Yo-Yo Ma tediously repeating a difficult passage, or Ronald Reagan practicing his speeches in front of a mirror, or Steve Jobs unveiling a half-baked iPhone. (The closest I came was the discovery of an early Rolling Stones draft of “Start Me Up.” Suffice it to say: The song does not work as a reggae tune.) You see only the final products. If we routinely fool others, they routinely fool us. So when we experience messy frustration, we too readily believe that we don’t have the right stuff and give up.