J ean Twenge a professor of social psychology has written an important article in the current Atlantic “Have Smartphones Destroyed a Generation?” that will provide much ammunition to parents concerned about their children’s use of iPhones iPods and various forms of social media.

Twenge’s research focuses on differences between generations. Beginning in 2012 she began to notice abrupt changes in teen behaviors and emotional states unlike any that she had previously encountered in 25 years of study. These were changes in kind not degree. She attributes these changes in what she terms “iGens ” those born between 1995 and 2012 to attachment to their smartphones. “I think we like our phones more than we like actual people ” Athena the 13-year-old protagonist with whom Twenge opens the piece tells her.

If Generation X (post-baby boomers) extended adolescence beyond all previous limits Twenge writes then iGen has extended childhood well into high school. Twelfth graders today spend less time together with friends than eighth graders in 2001. They are content to stay home and communicate via their electronic devices.

That change in behavior has not made them happier. Just the opposite. Without exception Twenge’s data show “All screen activities are linked to less happiness and all non-screen activities are linked to more happiness.” Correlation Twenge admits does not prove causation though she does cite one study in which college students’ online activities were closely monitored over two weeks: Use of Facebook led to higher reported levels of unhappiness but reported unhappiness did not lead to increased Facebook use.