“Digital devices are not eating away at our brains. They are, however, luring us toward near constant outwardly directed thought, a situation that’s probably unique in human experience. A flat cap on time with devices — the restriction we first think of for ourselves and our kids — might help. So would parking devices in another room for a while. But it would be more effective if we could learn to recognize in ourselves when escape from our thoughts is O.K. and when reflection is in order. As a bonus, judgments like that require inwardly directed attention, a mental habit that in our smartphone era, we’d be dumb to lose.”