The surprising origin of 4 features that superglue kids — and adults — to screens

What makes a person keep playing a video slot machine? Some of the same features that make children stay on social media apps or video games for too long. Paige Stampatori for NPR

Paige Stampatori for NPR

In two landmark cases, social media companies have been found liable for endangering and harming children. Meta and Google are appealing the verdicts and disputing the idea that their products are addictive. But over the course of more than a decade, scientists have identified key features of social media and other apps meant to hold children’s attention for as long as possible.