Among O.E.C.D. nations, the U.S. has one of the highest rates of child poverty. Until recently, it looked as if Washington was about to change that. But then … Washington happened.

Behavioral scientists have been exploring if — and when — a psychological reset can lead to lasting change. We survey evidence from the London Underground, Major League Baseball, and New Year’s resolutions; we look at accidental fresh starts, forced fresh starts, and fresh starts that backfire. And we wonder: will the pandemic’s end provide the biggest fresh start ever?