And because competencies are unmeasurable, it is impossible to prove or disprove the assertion that everyone who excels in a particular job possesses a particular set of competencies. It is equally impossible to show that people who acquired the competencies they lacked outperformed those who did not—that, in other words, well-rounded people are better. These two statements together are the foundation for most of what companies do to develop the talents of their people, yet each of them is unfalsifiable—you will find no academic papers in any peer-reviewed journal proving the necessity of possessing certain competencies, and no proof that acquiring the ones you lack nets you any increase in performance. Both of these assertions, despite the good intentions that created them, are conjured from thin air—and we can never know if they are correct.

Diversity isn’t an impediment to building a great team—rather, it’s the fundamental ingredient without which a great team cannot exist. If we were all the same, there would doubtless be things that all of us could not do, and that therefore the team could not do. We need to partner with people whose strengths—whose weirdness, whose spikiness—is different from ours if we are to achieve results that demand more abilities than any of us has alone. And this means, in turn, that the more different we are from one another, the more we need one another. The more different we are, the more we rely on understanding and appreciating the strengths of others, and on building a shared understanding of purpose, and an atmosphere of safety and trust, so that those strengths can be most usefully put to work. Well-roundedness is a misguided and futile objective when it comes to individual people; but when it comes to teams, it’s an absolute necessity. The more diverse the team members, the more weird, spiky, and idiosyncratic they are, the more well-rounded the team.

Therefore we know a) that the ability to learn exists in us all, b) that it shows up differently in each of us, and c) that while we can all get better at anything, none of us will ever be able to rewire our brains to excel at everything. More simply, we can all get better, and we will all get better at different things, in different ways, and at different speeds.

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.

A remarkable thing I’ve learned from my research is that in the growth mindset, you don’t always need confidence.

What I mean is that even when you think you’re not good at something, you can still plunge into it wholeheartedly and stick to it. Actually, sometimes you plunge into something because you’re not good at it. This is a wonderful feature of the growth mindset. You don’t have to think you’re already great at something to want to do it and to enjoy doing it.