At its annual WWDC developer conference on Monday, Apple announced new tools to help iPhone users monitor and limit the amount of time they spend on their devices. Cook said he'd been testing them out and was alarmed at what he found.
"I thought I was fairly disciplined about this, and I was wrong," Cook said. "When I began to get the data, I found I was spending a lot more time [on my device] than I should."
When asked, Cook declined to specify which apps were leading to his overuse.
"I don't want give you all the apps, but just too much," he said.
Tech developers, children's advocates, politicians, and others have been increasingly raising alarms about devices and apps encouraging addiction-like behaviour among their users. After shareholders filed a proposal earlier this year that would have urged Apple to do something to help iPhone users limit the time they spend on their devices, the company promised it would do just that.
In iOS 12, the upcoming version of the software that underlies the iPhone and the iPad, Apple is adding a collection of features that are designed to help people control how they use their devices. A feature called Screen Time will track how much time users are spending with particular apps.
One called App Limits will let them preset the amount of time they can spend with each one. And when users turn on the Do Not Disturb feature in iOS 12, they will be able to configure it so it blocks all of their notifications until they turn it off.
In terms of measuring the success of the iPhone, "We've never been focused on usage as a key parameter," Cook said. He continued: "We're empowering people with the facts that will allow them to decide themselves how they want to cut back."