Small says these differences are likely to be even more profound across generations, because younger people are exposed to more technology from an earlier age than older people. He refers to this as the brain gap. On one side, what he calls digital natives—those who have never known a world without e-mail and text messaging—use their superior cognitive abilities to make snap decisions and juggle multiple sources of sensory input. On the other side, digital immigrants—those who witnessed the advent of modern technology long after their brains had been hardwired—are better at reading facial expressions than they are at navigating cyberspace. "The typical immigrant's brain was trained in completely different ways of socializing and learning, taking things step-by-step and addressing one task at a time," he says. "Immigrants learn more methodically and tend to execute tasks more precisely."

Digital Information and the Human Brain