Talent identification is the holy grail of sports, business, parenting, and education. We dream of having the magical ability to quickly and accurately assess who is destined to succeed; to sort the contenders from the pretenders.

Funny thing is, there was once a clever scientist who figured out how to do just that.

His name was Dov Eden; he was an Israeli psychologist who worked with businesses and the military. In the early 1980s Eden published a remarkable study that showed he could predict with uncanny precision which young recruits in the Israeli military would become top performers.

It worked like this: Eden studied the mental and physical aptitudes of one thousand recruits, then selected a handful of soldiers he labeled as “high potential.” Eden informed platoon commanders that they could “expect unusual achievements” from these individuals.

Sure enough, Eden was right. Over the next 11 weeks, Eden’s group performed significantly better than their peers — 9 percent higher on expertise tests and 10 percent higher on weapons evaluation.

It looked for all the world like an impressive display of talent identification — except that it wasn’t.

Because here’s the twist: the “high-potential” soldiers weren’t really high-potential. Eden had selected them completely at random. The real power was in the act of labeling them as high-potential. In sending a simple signal — these people are special.

That signal had created a massive effect in both the mind of the instructor and the learner — a virtuous spiral between teacher and learner that led to the full expression of potential. (The phenomenon, dubbed the Pygmalion Effect, has been repeated many times, and is particularly powerful in educational settings.)

The story, told in Adam Grant’s marvelous new book Give and Take, gives us a glimpse into the power of labels, and how they affect our subconscious. The underlying picture: the unconscious minds of most teachers are naturally thrifty with energy and attention — after all, they don’t have all the time in the world.  They thus look at each new student with a questioning eye: do they have what it takes? Is this a good investment?

The high-potential label is like a flashing Las Vegas sign reading THIS PERSON IS A GREAT INVESTMENT — that triggers a cascade of positive effects. First impressions are uniformly positive. Early mistakes aren’t treated as verdicts; but as learning opportunities. Progress isn’t treated as luck, but as a happy inevitability.

I remember watching Hans Jensen, a remarkable cello teacher at Meadowmount Music School, teach two students. To my eye, one student was clearly better than the other. After the lesson, I asked Hans which student had more potential.

“Who knows?” he said.

I think this is precisely the kind of thinking that distinguishes master teachers. They share a hesitancy to judge; a stubborn, seemingly illogical optimism. They see failures as stepping stones to progress. They begin each new encounter with a single thrilling thought: this person is special.

And then, more often than not, that thought turns out to be true.