If two of the 20th century’s iconic technologies, the automobile and the television, initiated the rise of American aloneness, then screens continue to fuel and even accelerated, our national anti-social streak. Countless books, articles, and cable-news segments have warned Americans that smartphones can negatively affect mental health and may be especially harmful to adolescents. But the fretful coverage is, if anything, restrained given how greatly these devices have changed our conscious experience.

The typical person is awake for about 900 minutes a day. American kids and teenagers spend, on average, about 270 minutes on weekdays and 380 minutes on weekends gazing into their screens, according to the Digital Parenthood Initiative. By this account, screens occupy more than 30 percent of their waking life.