Living in Silicon Valley, I get the impression that teenagers are looking at their phones less than they were five years ago. A few years ago, I'd have to dodge people on sidewalks and in store aisles who had completely lost track of their surroundings. That seems to have stopped. I see teenagers pull out a phone, interact with it briefly, then put it away. Also, everybody seems to be in vibrate mode now; I seldom hear a ringtone.