Zuckerberg says the science isn’t settled. But the harms of short-form video on the brain are starting to show

‘Perhaps the safest way to approach the digital world, where we now spend most of our time, is to listen to our own minds and bodies.’ Photograph: Peter Cripps/Alamy

A few years ago, when I’d just started graduate work, I was waiting with a grandmother finishing a questionnaire I’d handed her about her 19-year-old granddaughter who was in the testing room next door. They were participating in a study that used brain imaging to look at adolescent development. The older woman had a soft southern accent and a warm laugh.

“What’s funny?” I asked.