Tristan Harris holds his iPhone in the air, so the whole crowd of educators, technologists, doctors, and researchers before him can see the virtual wasteland of his iPhone's home screen. Gone are the cluttered, candy-colored icons that a busy brain sees as digital snacks. In their place are but a few utilitarian apps, all set to the same bleak palette of black and white.

Harris, a former design ethicist at Google, wants to show his audience how they, too, can make their phones as visually unappealing as possible, reducing them to functional tools rather than time-sucking toys. He's not doing it to preserve their eyesight, or as some self-help hack to squeeze more time out of the day. Harris is conducting this demonstration because he believes the way tech tools intentionally manipulate the mind has become an existential threat to human beings. Giving the iPhone a makeover is one way to wrest some of that control from their inhuman grip.

"I see this as game over, unless we change course. Really. Genuinely," Harris said on stage Wednesday at a conference hosted by the children's advocacy group Common Sense Media. "We cannot live in this world."

If the rhetoric sounds scary, that's intentional. Earlier this week, Harris announced a newly formed coalition of technologists called the Center for Humane Technology, whose central goal is to spark a mass movement for more ethical technology, in order to put pressure on Silicon Valley giants like Facebook, Google, and Apple—the kind that the Center's leadership says has been entirely missing in Washington. The Center is partnering with Common Sense Media to plan, among other things, an ad campaign in schools across the country to educate parents, students, and even children about the dangers of technology addiction. The Truth About Tech conference Wednesday was the first push in that campaign, sending a signal to both DC and Silicon Valley that if they won't do anything to address tech's unhealthy impact, then maybe the public will.

'I see this as game over, unless we change course.' Tristan Harris, Center for Humane Technology

At yet, for all of the talk of a "tech backlash" in the United States, companies like Facebook and Google are still viewed favorably in polls. Despite the criticisms from both the left and the right, people are hardly marching by the thousands to protest Big Tech. But Harris and other leaders say maybe they would, if they only understood the way these tools are tailor-made to make addicts of all of us, forever altering the way some 2 billion people on Facebook alone think, feel, and interact with one another.

"This is a version of climate change," Jim Steyer, the CEO of Common Sense Media and brother of the billionaire environmentalist Tom Steyer, said on stage. "Just like we’re watching the extraordinary changes in our physical environment, we’re watching extraordinary changes in our social, emotional, and cognitive environment."

If Wednesday's event hoped to provide a spark, it largely came in the form of detailing how a group of young billionaires have enriched themselves by altering the chemistry of kid's brains. That may sound dystopian, but as Robert Lustig, a pediatric endocrinologist at University of California, San Francisco, made clear on stage, it is very much a reality.

Every time a kid collects coins in Minecraft, or catches a Charizard in Pokemon Go, their brain rewards them with a hit of dopamine. "It tells you, 'This feels good. I want more,'" Lustig explained. "But if you overstimulate dopamine neurons they die."

"We see the outgrowth of these changes in the brain that are manifesting themselves as mental illness in children," Lustig said, pointing to research that has shown spikes in the rate of depression and suicidal thoughts among kids over the last eight years. "It's not a drug, but it might as well be," Lustig said of the way tech is designed to give users constant rewards. "It does the same thing."