Most American teens and tweens have smartphones and spend hours each day streaming videos, playing games, and using social media. Phones can allow kids to be creative, help them explore new ideas, and connect them with peers who share their interests. But they also come with significant downsides: screen time can be a major distraction, expose young users to inappropriate or dangerous content, rob them of sleep, and increase the risk of depression and anxiety.

Psychologist Jean Twenge sounded the alarm about these risks nearly a decade ago. Her 2017 Atlantic article, “Have Smartphones Destroyed a Generation?”, sparked a national conversation about the impact of digital technology on kids.

As a mother of three daughters, Twenge knows firsthand how difficult it is for parents to monitor and manage their kid’s online lives. She argues that tech companies have failed to take responsibility for protecting young people and that parents have been left to pick up the slack. Her new book, 10 Rules for Raising Kids in a High-Tech World, gives parents the tools they need to help their kids develop a healthier relationship with social media. Twenge is a professor of psychology at San Diego State University.