We live in an age that's gushing with information and dizzying possibilities. You can almost feel your brain cells crackling to keep up with the choices—trivial and profound—that confront us at every turn: picking a cell-phone plan or an on-demand movie, selecting the best mix of investments in a 401(k) or the right health plan or just knowing which eggs to buy at the supermarket. (Cage free? Organic? Omega-3 enriched?) Surely there has never been a greater need to stay alert and informed, to act shrewdly and remain focused.
Luckily, we also live in an era in which research is showing...