Dawn Bradley, an early-childhood teacher, has spent enough time with three-, four- and five-year-olds to know that they often do not get the credit they deserve. Children “are just told to follow orders or are told to only answer yes-and-no questions,” she says. But in five years of teaching at Libertas School of Memphis in Tennessee, Bradley has seen kids persistently try to solve math problems until they get them right, learn to show courtesy when they accidentally bump into a friend, and ask astute questions about parts of insects or features of the nearby Mississippi River.