By the time the 15 minutes were up, they had spent only about 65 percent of the observation period actually doing their schoolwork.

Attending to multiple streams of information and entertainment while studying, doing homework, or even sitting in class has become common behavior among young people—so common that many of them rarely write a paper or complete a problem set any other way.

o detrimental is this practice that some researchers are proposing that a new prerequisite for academic and even professional success—the new marshmallow test of self-discipline—is the ability to resist a blinking inbox or a buzzing phone.