Prince Harry, long known for being an outspoken advocate on (especially men’s) mental health issues, is currently focused on a very tricky problem: that of social media and its effects on youth.

“In many cases, the smartphone…is stealing young people’s childhood,” he said in a conversation, a video of which was exclusively shared with Fortune this week, with social psychologist Jonathan Haidt, author of The Anxious Generation.

Haidt—whose four foundational smartphone rules have inspired both celebration and pushback—couldn’t agree more, explaining to Harry the premise of his book: that people born after 1995 (Gen Z, roughly) throughout the English-speaking world hit puberty with high rates of anxiety, depression, self-harm, and suicide, which all rose sharply between 2010 and 2012. And that it was no coincidence—but instead a direct result of the smartphone.

“Young people trade in their flip phones for smartphones,” Haidt said about that moment of generational shifting, “and now [have] a front-facing camera, high-speed internet, a million apps that are competing with each other to hook kids’ attention. So, the ‘anxious generation’ is helping us understand the incredible destructive force of this transformation of childhood…and what we can do now to stop that from happening and to help those who already have been through it.”

Haidt and the Duke of Sussex sat down for the intimate discussion (see the full video above) about social media and mental health as part of Harry’s Archewell Foundation 2024 Insight Sessions—public conversations, highlights of which appear in a new Insight Report—about the impact of technology, with the voices of youth front and center.

Here, some of the most powerful takeaways from the spirited conversation.

Parents vs. social media companies

One of Haidt’s biggest worries about the current state of parenting and social media is that “we are overprotecting our children in the real world and underprotecting them online,” he said. “And both of those moves are mistakes. They’re bad for development.” It’s why he advocates for no smartphones before high school, no social media before 16, phone-free schools, and more unsupervised play and childhood independence.

It’s also why, Harry said, “it’s very easy for social media companies to point the finger at parents and say, ‘Well, you know, this is down to you. This is down to your parenting.’”

But that’s an argument that Haidt rejects.

“If there were some parents who were getting this wrong and most parents were getting it right, then I’d be very receptive to that argument,” he said. “But once kids get a phone and social media, the rest of family life turns into a fight over screen time. And this is happening everywhere. This is happening in Silicon Valley, where the parents know what’s going on.”

So why do we give our 10-year-olds smartphones? “The main reason,” Haidt said, “is because everyone else did. We don’t want our daughter to be the only one who’s left out. I’m facing this now with my 14-year-old daughter on Snapchat. So the tech companies put us in a bind, and then they’re trying to blame us for what they did.” It’s why he’s also an advocate of collective action, or parents banding together to agree to delay the purchase of smartphones for their kids.

What about smartphones for safety?

Through his insight sessions, said Harry, he’s spoken with parents who say they give their kids phones at a younger age to keep them safe.

“It’s a double-edged sword,” he said. “They want them to have their phone at school in case of emergency, but once, like any kid, you have your phone, even if you’re told you’re not allowed to download that app, kids have a way of working around it.”

Haidt’s not buying the safety argument, though. “If you want to give your kid a phone, so if anything goes wrong they can call you, great. Give them a phone. Just don’t give them a supercomputer connected to everyone in the world… They don’t need that. The millennials had flip phones. They went through puberty with flip phones to call each other, text each other, meet up. It came out fine.”

Gen Z, on the other hand, “went through puberty with a supercomputer blocking out almost everything else in life,” he said. “Everything goes down: much less time with friends, much less sunlight, very many fewer books, many fewer hobbies. You take almost everything out of childhood. You replace it with this and a bunch of million short videos. It’s not much of a childhood.”

The ‘myth’ of social media as lifeline

Prince Harry then raised the idea of social media having a positive—and even lifesaving—side.

“Social media, we know, to a large extent, is giving an outlet, an added resource, to kids that perhaps don’t feel comfortable coming to us to talk about their issues and their troubles and their worries,” he said. “Kids online will be feeling more connected with complete strangers on social media. So how do you, if you’re a parent, know that your kid is getting good out of social media?”

Haidt said it is “one of Meta’s favorite talking points” that “social media is a lifeline for LGBTQ kids, for kids from marginalized communities. And that’s just not true.”

What is true, he said, “is that the internet was great for them. The internet solved all these problems in the ’90s. If you’re a gay kid, you’re not out to anyone in a rural part of America or England, the internet was amazing. You could find information, you could find people like you, and you could communicate.” But social media, Haidt insisted, has changed all that.

“It’s no longer even about just me connecting to you,” he said. “It’s now about an algorithm-driven news feed that sends content to you. This is not what they need. If you have any special interest, you can find that with Google. You don’t need an algorithm to feed you stuff.

So it’s “a myth,” he said, that Instagram and TikTok are lifelines. “The research, I think, is very clear: When kids have a best friend or especially a small group [of friends], they generally do well. When kids don’t have a close friend or close group, they’re much less likely to do well. When you have 300 connections, you don’t have time for anyone.”

More on mental health:

Stigma keeps many men from seeking mental health support. These 3 shifts in thinking can help
Chappell Roan drops out of music festival to prioritize health
Gen Z’s anxiety is spilling into the workplace. Here’s how to effectively manage the ‘anxious generation’

Exclusive: Prince Harry and ‘The Anxious Generation’ author talk social media and mental health