The $1.75 trillion Build Back Better plan, which the House passed in November, has been stalled in the Senate largely due to opposition from Sen. Joe Manchin, a moderate West Virginia Democrat, to some proposals, including extending a beefed-up version of the credit. The monthly payments, up to $300 per month for young children, ended in December. shows most families have used the money for rent, groceries and school-related expenses.

鈥淭he expanded [Child Tax Credit] is a signature domestic policy achievement of this administration, and has been an overwhelming success,鈥� Sens. Michael Bennet of Colorado, Sherrod Brown of Ohio, Cory Booker of New Jersey, Rev. Ralph Warnock of Georgia and Ron Wyden of Oregon wrote in . 鈥淎fter historic progress, it is unacceptable to return to a status quo in which children are America鈥檚 poorest residents and child poverty costs our nation more than $1 trillion per year.鈥�

The senators鈥� letter comes a week after Biden cast doubt on his ability to reach a deal with Manchin that includes the expanded credit. In a Jan. 19 press conference, he said he cares 鈥渁 great deal鈥� about the credit and said he would keep trying to get it passed. The senators also highlighted showing such policies can have positive impacts on babies鈥� brain development. With the Senate soon expected to return to over Build Back Better, the question is whether the study could influence Manchin鈥檚 position.

Supporters of cash support for low-income families are 鈥渜uite enthusiastic鈥� about the findings, said Greg Duncan, an education professor at the University of California, Irvine, and a lead researcher on the $17 million project. He鈥檚 working with advocacy groups in West Virginia to schedule a briefing for Manchin, and added that the researchers have 鈥渢ried to connect with all sorts of people on the political spectrum.鈥�

The first U.S. evaluation of a 鈥渄irect poverty reduction鈥� focused on early childhood, according to the press release, the study randomly assigned 1,000 low-income, mostly Black and Hispanic mothers in four cities to receive debit cards with monthly payments of either $333 or a nominal $20. After one year, infants in households that received the assistance were more likely than those in the control group to show brain activity associated with thinking and learning.

The researchers suggest that the cash support can reduce stress on mothers and in turn improve home environments for young children. The study began before the pandemic, but by researchers at the University of Oregon have shown that lockdowns, family isolation and financial stress related to COVID-19 have led to greater anxiety among parents and irritability among children.

While researchers can鈥檛 predict if children in the families receiving the payments will continue to have an advantage, they didn鈥檛 expect to see such quick results.

鈥淚t surprised most of us that after only one year of [cash] transfers that this would actually show up as clearly as it did in the data,鈥� Duncan said. 鈥淲e always take the long view and thought it would take several years before the stress levels would be reduced.鈥�

A second paper focusing on whether mothers spent the money on drugs or alcohol is expected this spring, followed by a third looking at whether the financial support is associated with mothers pulling out of the workforce. Critics, including Manchin, argue such programs should have a work requirement.

Duncan said that the findings add to a body of evidence that suggests 鈥渋ncome has a causal effect on child well-being, particularly in early childhood and when poverty is quite persistent.鈥�

Katharine Stevens, founder and CEO of the Center on Child and Family Policy, called the study an 鈥渦nusually rigorous attempt to begin identifying the most effective, policy-relevant drivers of child well-being.鈥� But she rejected the suggestion that the money was a direct cause of the brain growth in children.聽

Babies 鈥渄o not eat, breathe or interact with money,鈥� she said, adding that more research is needed to determine the 鈥渕echanisms that matter most鈥� in young children鈥檚 development.