Everybody has that one teacher who changes his or her life forever. For us, that person was a tough-as-nails New Jersey music teacher named Jerry Kupchynsky - known as "Mr. K." He pushed us harder than our parents, harder than our other teachers, and made us better than we had any right to be. It was only later that we realized how much we loved him for it.

If Mr. K wasn’t a real-life character, somebody would have had to invent him. A Ukrainian-born taskmaster, he yelled and stomped and screamed. But he also pushed us to dream bigger and to achieve more than we ever imagined. What’s remarkable is that he did all this while enduring a life of almost unimaginable tragedy.

His is an unforgettable story about the power of a great teacher, but also about resilience, excellence, and tough love. Mr. K’s subject, of course, was music. But the lessons he taught his students are universal.

It’s hard to imagine a Mr. K in today’s world. Parents would be outraged; administrators would be pressured to fire him. Yet he was remarkably effective. His methods raise the big issues we grapple with now ourselves, as parents. Are we too soft on our kids? How do we best balance discipline with praise? How hard do we really want our kids’ teachers to push them? And if our kids do complain, how do we know when—or if—to interfere?

The latest research on kids and motivation, it turns out, comes down in Mr. K’s corner. Recent studies have turned conventional wisdom on its head, concluding that overpraising kids makes them less confident and less motivated. Psychologist Carol Dweck, for instance, found that fifth graders praised for being “smart” became less confident, while those told they were “hard workers” became more confident and performed better.

Similar findings have transformed our understanding of business success. In his 2008 book Outliers, Malcolm Gladwell popularized the notion that true expertise requires 10,000 hours of practice.

He cited examples—Microsoft founder Bill Gates, for one—and credited the work of the Swedish psychologist K. Anders Ericsson. Perhaps it shouldn’t be surprising that Ericsson’s initial work was based on a study he did not of executives—but of violinists.

Ericsson expanded his research to the business world with a 2007 Harvard Business Review article, “The Making of an Expert.” He and his coauthors identified three key steps that all experts take, including those 10,000 hours as well as deliberate practice with a teacher. Perhaps most significant was the third step:

The development of expertise requires coaches who are capable of giving constructive, even painful, feedback. Real experts . . . deliberately picked unsentimental coaches who would chal- lenge them and drive them to higher levels of performance.

In other words, real experts don’t want soft teachers: They want tough ones. Unsentimental ones. Ones who give them “painful” feedback.

We couldn’t imagine a more accurate description of Mr. K.

That research helped us to answer a key question: What was it that made Mr. K so effective?

“Discipline. Self-confidence. Resilience. These are lifelong lessons,” as one of his old students told us. “Whether we stuck with the music or not, it stuck with us.”

Mr. K was without a doubt the toughest teacher we ever met. But his legacy is proof that one person can make all the difference. And that legacy endures. Its power was clear when, after his death, forty years’ worth of former students flew in from every corner of the country, old instruments in tow. They were inspired to take leave of their busy lives because they never forgot the lessons he taught them. And they were determined to thank him in the best way they knew how: by playing one last concert together, this time for Mr. K.
 

***Excerpted from STRINGS ATTACHED: One Tough Teacher and the Gift of Great Expectations by Joanne Lipman and Melanie Kupchynsky.  A Hyperion Books Hardcover. Copyright © 2013 Joanne Lipman and Melanie Kupchynsky. All rights reserved. No part of this book may be used or reproduced in any manner whatsoever without the written permission of the Publisher.***