Beware of the einstellung! No, it is not a mythical Bavarian monster. Einstellung (EIN-shtell-ung) is something much more prosaic and universally human: the tendency to get stuck in a mental rut. For all of its marvels, the human mind is notoriously lazy—reluctant to use energy except when absolutely necessary. As children, we explore every possibility, but as we grow, we develop routinized ways of handling most challenges and the alternative neural pathways die off. This can free up mental ene...