1. Responding Like a Trained Monkey Every productivity expert in the world will tell you to check email at periodic intervals — say, every 90 minutes — rather than clicking “refresh” like a Pavlovian mutt. Of course, almost no one listens, because studies have shown email’s “variable interval reinforcement schedule” is basically a slot machine for your brain. But spending a month away — and only checking email weekly — showed me how little really requires immediate response. In fact, nothing. A 90-minute wait won’t kill anyone and...