Speaking at Harlow College in England, Apple CEO Tim Cook said schools should limit the use of technology in the classroom and that he doesn’t want his nephew to use social media, The Guardian reports.

“I’m not a person that says we’ve achieved success if you’re using [technology] all the time,” Cook said. “I don’t subscribe to that at all.”

Cook visited the school for the launch of Apple’s Everyone Can Code curriculum and said he believes deeply in the importance of teaching coding.

“I think if you had to make a choice, it’s more important to learn coding than a foreign language,” he said. “I know people who disagree with me on that. But coding is a global language; it’s the way you can converse with 7 billion people.”

As part of Apple’s new curriculum—which is being brought to 70 institutions across Europe—every student at Harlow College receives an iPad “loaded with coding apps and tools.” But the tech mogul said he thinks schools would be wise to limit the use of technology in the classroom—even in courses that require using and understanding it, such as graphic design.

“There are are still concepts that you want to talk about and understand,” Cook said. “In a course on literature, do I think you should use technology a lot? Probably not.”

Cook said his thoughts on young people and technology use extends beyond the classroom, noting, “I don’t have a kid, but I have a nephew that I put some boundaries on. There are some things that I won’t allow; I don’t want them on a social network.”

His comments come in the wake of an open letter from Apple shareholders pushing Apple to focus more on the issue of youth phone addiction and parental controls.

Cook is not the first tech executive or investor to express concern over the impact that the products they are putting into the world could have on family members and youth in general.

Tony Fadell, founder of smart thermostat company Nest and one of the designers of the iPhone and iPod, shared at a 2017 panel that he often wonders, “What did we bring to the world?” He said he sees concerning results when he takes technology away from his own children. “They get emotional about it, very emotional. They go through withdrawal for two to three days.”

On The Thrive Global Podcast, business mogul Mark Cuban told Thrive Global founder and CEO Arianna Huffington about the “downside of having a geeky dad.” Cuban, who has invested heavily in Netflix, has a system set up to monitor the apps his kids are using and makes them earn hours watching videos online (including Netflix.) For example, Cuban said, “If [my son] watched math videos or did math problems for me, he could earn time to watch Minecraft videos.”

Former Facebook president Sean Parker recently expressed his concerns over how Facebook and other social media sites are affecting people around the world. “The thought process that went into building these applications, Facebook being the first of them…was all about ‘How do we consume as much of your time and conscious attention as possible?’” he said. “God only knows what it’s doing to our children’s brains.”

In the growing conversation surrounding our relationship with technology, important figures in the tech world are increasingly voicing concern. And when it comes to overusing technology— from social media to screen time in general—they seem to be among those setting the strictest rules for the people close to them.