The differences were modest — researchers likened them in statistical magnitude to moving to the 75th position in a line of 100 from the 81st — and it remains to be seen if changes in brain patterns will translate to higher skills, as other research offers reason to expect.

Still, evidence that a single year of subsidies could alter something as profound as brain functioning highlights the role that money may play in child development and comes as President Biden is pushing for a much larger program of subsidies for families with children.

“This is a big scientific finding,” said Martha J. Farah, a neuroscientist at the University of Pennsylvania, who conducted a review of the study for the Proceedings of the National Academies of Sciences, where it was published on Monday. “It’s proof that just giving the families more money, even a modest amount of more money, leads to better brain development.”