Meet the Laffey family of Billerica, MA., a middle-class suburb northwest of Boston. The parents, Kevin and Shelly, both work. Their two teenaged children, Chris and Nicki, attend local high schools. Increasingly, all four rely on their screened devices - televisions, computers, cellphones - to communicate and consume information, to manage work-related data, to be educated, entertained, and so on. Like millions of Americans, the Laffeys are living in a Screen Society, for better or worse. A portrait of one family’s screen usage, the first in an occasional series called Living With Screens, running year-long in the Boston Globe.