Dinnertime has become a free-for-all in many households, with packed family schedules and the television on in the background. Experts talk repeatedly about setting, and how it affects manners and behavior. This concept comes from the field of criminology. “A fancy restaurant gives off so many cues that this is a place for refined behavior,” said Ralph Taylor, a professor of criminal justice at Temple who studies how environments influence behavior. And environment changes not just the youngsters. “The parents are changed,” he added. “You’re not talking loud; you’re not yacking on the cellphone. Everybody is with the program.”