As governments worldwide move to restrict teenagers’ access to smartphones and social media, a fierce scientific debate has erupted over whether these digital technologies actually harm young people’s mental health. The controversy, sparked by an influential recent book blaming phones for rising youth anxiety, has exposed deep uncertainties in the research evidence – even as policymakers from Arkansas to Australia forge ahead with sweeping bans and restrictions. A timeline of the controversy In March, New York University social psychologist Jonathan Haidt published a popular science book called The Anxious Generation. This blames a rise in youth mental illness over the…