Are we getting smarter? A popular new book tries to make the case, but Malcom Gladwell wonders what kind of “smart” we’re talking about. “Being “smart” involves facility in both kinds of thinking—the kind of fluid problem solving that matters in things like video games and I.Q. tests, but also the kind of crystallized knowledge that comes from explicit learning. The real question is what the right balance of these two forms of intelligence might look like.”