Schools across the U.S. are starting to rethink the abundance of digital devices in classrooms. After pouring billions of dollars into laptops, tablets and learning apps, a growing number of schools say it is time to scale back. The Los Angeles public school system announced it will stop giving its youngest students devices, as part of a sweeping new screen policy in the nation's second-largest school district. Concerned parents are driving the reforms. As one mother says: Her daughter came home from school “with a screen addiction in her backpack.”