We took a trip to Japan in 2008, and I was struck by how many people on trains seemed to be glued to the screens of their cellphones (smartphones or smart-enough phones). The adoption of smartphones was only just picking up in the United States, and while it wasn't unusual to see people talking or texting, I don't recall people becoming wholly engaged in their phone screens for extended periods the way they seemed to be in Tokyo. But that has all changed. Now it's commonplace to see people walking down the street entranced by Facebook, Twitter, Foursquare, Yelp, Groupon, some latter-day version of Pong, or the works of Voltaire (or all of the above in sequence, while listening to "Viva la Vida").
I've never become comfortable plugging in earbuds and listening to music as I walk down the street; I immediately feel disconnected from my surroundings in a way I don't quite trust--I don't hear traffic as well, or other people, or my own footfalls. As the saying goes, your mileage may vary; I know plenty of people for whom this isn't an issue, including folks who run long training distances and even endurance cyclists. Of course, when people are listening to music while training, they're using it as part of the routine, to inspire and pace themselves (and I've always loved group indoor-cycling workouts for the music part of it; the music is part of the shared experience).
You don't need a smartphone or iPad or anything electronic to put up a wall between you and your surroundings. A newspaper or book can achieve that effect quite nicely. On a noisy, crowded train after a demanding day at work. I think it's natural to want to create your own little bubble and retreat into it. I remember the first time I did a daily commute, when I was 18, watching people diving into their paper for the hourlong ride (me, I used the time to catch up on my sleep, and still do when I take the rain to work).
But that's one of the reasons I like to walk from work, across a hill or two, and over to the bay to catch the ferry every once in a while: to make contact with the world, to see it, to be part of it. And of course, offer my critique of the proceedings around and about. All of which leads to the two guys above, pictured on the ferry to Oakland from San Francisco yesterday. The one on the left never looked up; I assume he was reading a book or important memo on his device. The one on the right barely looked up. Me? Well, when I wasn't checking on my fellow passengers and documenting their activities, I was standing at the aft end of the boat's top deck, watching the sunlight on our wake.