A new study has found that babies of poor mothers who received cash stipends last year had changes in their brain activity patterns. As the expanded, refundable child tax credit (CTC) has expired and key politicians, in particular Sen. Joe Manchin III (D-W.Va.), have been withholding their support for reviving this important anti-poverty program, its supporters have expressed hope that this finding will perhaps help seal the deal. The expectation is that if cash benefits can improve the neurological development of infants, sustaining this policy is a no-brainer. As a pediatrician recently tweeted to his 30,000 followers, policy impacts biology.

Not so fast. This line of argument suggests that ending poverty in its own right is not a sufficient goal and that improving the brain function and biology of poor babies should drive policy. We have seen this before. In the 1960s, for example, Great Society policymakers worked to develop numerous anti-poverty interventions. Yet many of these valuable programs overpromised what they could achieve in children’s development, even claiming they would raise children’s IQs.

When these programs subsequently did not result in such measurable outcomes, they were roundly criticized and suffered a crippling lack of public support — even when they did achieve other meaningful anti-poverty goals. This is particularly clear with Project Head Start, the early-childhood education program pioneered in 1965. Its history points to the pitfalls of such thinking for CTC and anti-poverty advocates today.

Early enrichment was a popular anti-poverty measure in the 1960s. Scholarly research showed that children from poor families arrived to school unprepared and thus their academic achievement suffered. Scholars theorized that deficits in children’s home environment were leading to these poor outcomes. They likened the effect to that seen in experimental studies in sensory deprivation.

Legislators embraced these findings as they worked on policy interventions, and their reasoning went something like this: Poor children’s home environments were drab and colorless, devoid of interaction and lacking in books, and poor mothers failed to engage their children in a stimulating manner. Poor children, like experimental monkeys raised in darkness or in isolation, simply did not receive the necessary stimulation for their brain development. Placing these children in early-enrichment centers would help rectify these deficits and enhance their intellectual development.