Of course, if we were able to watch a great athlete training, or a great writer writing, or a great coder coding, we would see that honing a strength is hard work—it is by no means easy to find that incremental margin of performance when you are already operating at a high level—and that a strength is not where we are most “finished” but in fact where we are most productively challenged. Yet we are told to resist the temptation to “just” play to our strengths, and instead to work constantly on our weaknesses. In common parlance, we are told to avoid “running around our backhand.” This betrays, perhaps, a misunderstanding of what a strength actually is. It is not, for each of us, where performance is easiest—it is where performance is most impactful and increasing.

Is there another way to judge potential? NASA thought so. When they were soliciting applications for astronauts, they rejected people with pure histories of success and instead selected people who had had significant failures and bounced back from them. Jack Welch, the celebrated CEO of General Electric, chose executives on the basis of “runway,” their capacity for growth. And remember Marina Semyonova, the famed ballet teacher, who chose the students who were energized by criticism. They were all rejecting the idea of fixed ability and selecting instead for mindset.

It’s also important to realize that even if people have a fixed mindset, they’re not always in that mindset. In fact, in many of our studies, we put people into a growth mindset. We tell them that an ability can be learned and that the task will give them a chance to do that. Or we have them read a scientific article that teaches them the growth mindset. The article describes people who did not have natural ability, but who developed exceptional skills. These experiences make our research participants into growth-minded thinkers, at least for the moment - and they act like growth-minded thinkers, too.

The students with growth mindset completely took charge of their learning and motivation. Instead of plunging into unthinking memorization of the course material, they said: “I looked for themes and underlying principles across lectures,” and “I went over mistakes until I was certain I understood them.” They were studying to learn, not just to ace the test. And, actually, this was why they got higher grades—not because they were smarter or had a better background in science.

Instead of losing their motivation when the course got dry or difficult, they said: “I maintained my interest in the material.” “I stayed positive about taking chemistry.” “I kept myself motivated to study.” Even if they thought the textbook was boring or the instructor was a stiff, they didn’t let their motivation evaporate. That just made it all the more important to motivate themselves.

I asked, “If you could pick one trait that would predict how someone would turn out, what would it be?”

“That’s easy,” he said. “How willing they are to change their mind about what they think they know.”

The most valuable people, he continued, weren’t the ones with the best initial ideas, but the ones with the ability to quickly change their minds. They were focused on outcome over ego. By contrast, he said, the people most likely to fail were those obsessed with minute details that supported their point of view.