The interest in UBI doesn’t necessarily translate to support for Yang’s plan. Rhodes declined to comment on Yang’s approach. Even Altman, who has made personal donations to Yang and held fundraisers for his campaign, said the candidate still needs to develop the plan’s details. “It’s not a policy that I would implement today,” Altman said. He wants to see the results of YC’s research before settling on an approach, and is concerned about striking the right balance between cash assistance and funding services like education. Altman also said he preferred distributing a “fixed percentage of the money generated by a society each year, not a fixed dollar amount, so that the better a society does, the better everyone does in a very direct way.”

Chris Hughes, one of the co-founders of Facebook Inc., in late 2016 helped start the Economic Security Project, a group pushing for what it calls “unconditional cash stipends.” His group is funding a research project giving 125 people in Stockton, California $500 a month for 18 months. With the support of the city’s mayor, researchers sent a letter to everyone who made less than $46,033, the median income for the city. Then they randomly selected families to receive money.

Natalie Foster, co-chair of the Economic Security Project, also met with Yang before his presidential run. But unlike Stern, she’s not supporting him. Her group has dropped its insistence on the idea of “universal” income, proposing limiting payouts to just those that need it.

Foster also takes issue with Yang’s plans to pay for his freedom dividend. Yang’s version would implement a so-called value-added tax on everyday consumption to pay for his Freedom Dividend. This would affect everyone, and people on the left have generally supported paying for social programs with targeted taxation on the rich. “We would favor a way of paying for the policy that's more progressive, something like a wealth tax,” said Foster.

Yang has adjusted his guaranteed income proposal during the campaign. He’s had to grapple with what to do about poor people who would no longer qualify for existing government services like food stamps once they receive $12,000 a year from the government. Yang now says he’d give people the option between the two programs. More progressive versions of the proposal would give people both.

For some of Yang’s supporters, one appeal of the plan is how it doesn’t fall easily into existing political camps. “He convinced me that universal basic income is the best way forward,” said Pradhyumna Agaram, an engineer at the augmented reality company Magic Leap who became a die-hard Yang supporter after he watched an interview with the candidate on Joe Rogan’s popular podcast. “He's not ideological. Everything is based on logic and data.”

Over the course of Yang’s campaign, support for UBI has increased, according to polling data. Voter support for UBI grew to 49% in September, up from 43% in February, according to a Hill-HarrisX poll. According to an Emerson college poll conducted in January, 53% of potential Iowa caucus voters now support Yang’s UBI plan, with 30% of them opposing it. 

None of the leading Democratic candidates have taken up UBI. But they have various proposals based on related ideas. Many want to expand child tax credits, increasing the credit available to parents based on how many children they have, regardless of whether they work. Some candidates also support expanding the earned income tax credit.

In Congress, Representative Rashida Tlaib introduced a bill in June that would offer money unconditionally to individuals earning less than $50,000 and married couples earning less than $100,000 a year, a version of a bill introduced the year before by Senator Kamala Harris. An unemployed person could receive up to $3,000, without cutting into their social security or disability payments. Another proposal introduced by Senator Sherrod Brown with widespread Democratic support would offer the child tax credit to families regardless of whether they were working.