Inspired by American behavioral economics, the British government is finding new ways to gently prod people to pay taxes, find jobs and insulate their homes. A 24-year-old psychologist working for the British government, Mr. Gyani was supposed to come up with new ways to help people find work. He was intrigued by an obscure 1994 study that tracked a group of unemployed engineers in Texas. One group of engineers, who wrote about how it felt to lose their jobs, were twice as likely to find work as the ones who didn’t. Mr. Gyani took the study to a job center in Essex, northeast of London, where he was assigned for several months. Sure, it seemed crazy, but would it hurt to give it a shot? Hayley Carney, one of the center’s managers, was willing to try.