> That reliance on self-reporting — the teens' own opinions — as a single indicator of harm is a problem, says Candice Odgers, a psychologist who studies adolescence at University of California, Irvine and Duke University. That's because teenagers are already primed by media coverage, and the disapproval of adults, to believe that social media is bad for them.

And since when do teens care about the disapproval of adults? When I was a kid, video games were the terrible thing. I didn't know any kids who bought into that narrative—we knew they were harmless fun and kept playing.