" Some people argue that part of the reason U.S. students don’t do as well on international measures of high school knowledge is that they’re doing too well in class,” Nate Kornell, a cognitive psychologist at Williams College, told me. “What you want is to make it easy to make it hard.” Kornell was explaining the concept of “desirable difficulties,” obstacles that make learning more challenging, slower, and "

― David Epstein , Range: Why Generalists Triumph in a Specialized World