The invention of "Prime time"—the attentional habit of turning on the radio (later, the television) at the designated hour each and every evening of the year—was a momentous cultural as well as commercial innovation at a point when the two categories were drifting steadily closer. For it transformed not only the industries equipped to capture attention, but also the lives of those whose attention was now there for the taking. We have already remarked how who we are can be defined, at least in part, by what we attend to—how much more so this is when what we attend to is determined less by our volition and more by ambience. When we speak of living environments and their effects on us, then, we are often speaking too broadly—of the city, the countryside, and so on. Our most immediate environment is actually formed by what holds our attention from moment to moment, whether having received or taken it. As William James once put it, "My experience is what I agree to attend to."

Tim Wu, The Attention Merchants, loc. 330