As our electronics shrink, we more and more insulate ourselves from the outside world. “Each of us populates a personal tech-bubble of one. Solo-tech-travelers often are unaware that others occupy the same dimensions as them — that’s why they often bump into others, in their cars or on foot. If you don’t jump out of the way, they’ll jostle you with the outer edges of their bubble while text-messaging someone about something urgent — like, ‘wnt pzza 4 dnnr?’ “