Jovan Bravo and his wife knew they wanted to move, but could never quite make it happen: They would sock away $100 to $150 a month and then have an expense come up—a car breaking down, their daughter’s gymnastics lessons—that would deplete their savings. Then they’d start over again. “The hardest part of it was trying to save up a $2,000 deposit when you’re living check-to-check,” he said.

Bravo, a soft-spoken 32-year-old, grew up in Stockton, a diverse, high-poverty city in California’s Central Valley. He had a decent job working in cement but still found himself struggling with rising housing costs as people from nearby San Francisco and Silicon Valley—many who were themselves looking for relief from an affordability crisis—moved into the area. Things were cramped in a two-bedroom with three kids, Bravo said, but a bigger home in a safer neighborhood was out of reach: “Everything in Stockton is going up.”

This more or less seemed like how things would stay, until Bravo opened his mailbox one day in December 2018 to find a letter addressed to “Stockton Resident.” “Your household has been randomly selected to participate in the Stockton Economic Empowerment Demonstration, also known as SEED,” the letter started out. “SEED will provide $500 a month to a group of Stockton residents for 18 months.”

The SEED project, which started sending out checks in February 2019, is testing an idea that has floated around in academic and philosophical debates for centuries: that giving people money, no strings attached, can improve their lives without any negative repercussions. Known as universal basic income, or UBI—sending regular infusions of money to everyone—it’s not a new idea, dating as far back as Tudor England. Thinkers ranging from Martin Luther King Jr. to Milton Friedman have backed it, and President Richard Nixon nearly enacted his own version in the form of an unconditional payment for all families with children.

But beyond some accidental experiments, it has yet to get a real-life test here in the United States. So SEED is seeking to answer some key questions: Can a basic income benefit not just people’s finances but their well-being in ways that could change their life trajectories? Or will the additional cash fail to make a meaningful difference? These questions have gained salience as work has become more precarious and wages have failed to keep up with an otherwise booming economy. Against these conditions, the thinking goes, basic income could offer every American, no matter their station or status and no matter the state of the economy, a financial net. Stockton, which SEED researchers felt was a representative city because of the strength of its diversity and the concentration of its poverty, was selected as the laboratory. And residents like Bravo are the guinea pigs.