It turns out that the biggest bottleneck in behavior—in other words, the shortfall that most frequently prevents inclination, ability, and sensitivity from coalescing into sustained cognitive activity—is a shortfall of sensitivity. In other words, at least in terms of critical and creative thinking, young people don’t follow through with these habits of mind not because they can’t (ability), and not because they don’t want to (inclination), but mainly because they don’t notice opportunities to do so.