Sean Parker, the former president of Facebook, has joined the ranks of other innovators of now-ubiquitous technologies, like Bill Gates and iPhone designer Tony Fadell, to voice concerns about the creations they’ve unleashed on the world, Mike Allen reports for Axios.

Parker is now the chair of the Parker Institute for Cancer Immunotherapy (and full disclosure, an investor in Thrive Global). In the green room of an Axios event on innovation in cancer treatment, Parker said he’s become “something of a conscientious objector on social media.”

“When Facebook was getting going, I had these people who would come up to me and they would say, ‘I’m not on social media,’” Parker said. “And I would say, ‘OK. You know, you will be.’ And then they would say ‘No, no, no. I value my real-life interactions. I value the moment. I value presence. I value intimacy.’ And I would say,… ‘We’ll get you eventually.’”

And they did get most people—Facebook is the most widely-used social platform in the U.S., according to Pew Research Center, and just under half of Americans get their news from it (which is just a tad problematic, given the whole issue of foreign interference in the 2016 election via the platform). As of June 2017, Facebook reported 2 billion active monthly users, and as of last year, Facebook stole an estimated 50 minutes of each user’s attention each day. That figure could be higher by now, and likely is for avid users.

Facebook doesn’t amass so many users—and so many minutes of our time—just because it’s fun and people want to constantly update their statuses. It’s designed to exploit how our brains work and keep us online for as long as possible.

“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?” Parker said in the green room.

As Ramsay Brown, COO and founder of Dopamine Labs—which studies the very algorithms that start and break these tech addictions—told me earlier this year, big brands are the customers of social networks while “our attention span, and our consumer preferences, are the things to be auctioned off.”

That means when you try to will yourself to stop checking Facebook, it’s not actually a question of willpower—it’s about how your brain works. It’s a “social-validation feedback loop,” Parker said. “Exactly the kind of thing that a hacker like myself would come up with, because you’re exploiting a human psychology.”

As Brown told me, this means that a team of engineers is using algorithms to fine tune “when and how you’re shown different things, when and how you’re given your likes.”

That gives you “a little dopamine hit every once in a while because someone liked or commented on a photo or post of whatever,” Parker said, which will then get you to comment, like, share and contribute more content. And this is true of many social networks, not just Facebook: “Inventors, creators—it’s me, it’s Mark [Zuckerberg], it’s Kevin Systrom on Instagram, it’s all of these people—understood this consciously. And we did it anyway.”

And like any good creator with questions about the morality of his now monstrous creation, Parker acknowledged that there’s a difference between how nefarious these techniques seemed at Facebook’s inception versus how they’re being used today. “I don’t really know if I understood the consequences of what I was saying, because [of] the unintended consequences of a network when it grows to a billion or 2 billion people,” he said.

And it is doing weird things to our productivity and our brains. Facebook, like other social networks, can help people feel more connected to others, which is generally a good thing for mental and physical health. But it also can make us anxious, depressed and conflicted about our body image thanks to the ease with which social media lets us compare ourselves to others, among other downsides.

Parker’s words may not change the social network or the way we use it. But the fact that yet another person who was involved in creating a now pervasive technology platform is openly acknowledging its power and influence is important. If we are to think critically about how these platforms are reshaping our world and relationships, the people who created them have to be part of the conversation.

Read the full article on Axios. And for more information on how social media keeps us hooked—and tips on how to set healthy boundaries with technology—visit our Time Well Spent section.