PERSON
Jean Twenge
The generational psychologist who documented, across decades of nationally representative data, that the smartphone reshaped adolescent mental health in measurable, dose-dependent ways—and whose framework now predicts, with uncomfortable precision, what AI is about to do to the generation that smartphones left already wounded.
Twenge is the scientist of the trend line—the researcher who looks at what everyone dismisses as background noise until she shows it is a signal. Her methodology is straightforward but unusual in its scale: she analyzes large, nationally representative surveys that have been administered to hundreds of thousands of respondents over decades, looking for the moments when generational cohorts diverge from historical patterns. What she found, in data no one else had assembled quite this way, is that in 2012 something broke. Between 2012 and 2019, rates of major depressive episodes among American teenagers increased by sixty percent. Teen suicide rates rose by fifty-six percent. The percentage of high school seniors reporting loneliness climbed from twenty-six to thirty-nine percent. Emergency room visits for self-harm among girls aged ten to fourteen nearly tripled. And the inflection point coincided, with statistical sharpness, with the year that smartphone ownership crossed fifty percent among Americans.
The 2012