The impact of a monthly unconditional cash transfer on child brain activity: A 4-year follow-up

Early childhood poverty is associated with neurodevelopmental differences, but causal evidence linking income to brain development is sparse. In the present study, we examine whether four years of monthly unconditional cash transfers to mothers experiencing low income cause differences in their preschoolers' brain activity. Shortly after giving birth, mothers were randomized to receive $333/month or $20/month for the first several years of their child's life as a part of the Baby's First Years study. Here we report on the impact of these cash gifts on resting brain electric activity recorded at 4 years of age as measured by electroencephalography (EEG). We find no impact on our primary preregistered outcome (an aggregated index of mid-to-high-frequency brain activity) or our secondary preregistered outcome frontal gamma power. We did find, in additional exploratory analyses that were part of our pre-registered analytic plan, that preschoolers in the high-cash gift group had higher alpha power compared to those in the low-cash gift group. There were no differences in theta, beta, or gamma power between groups. Although the primary and secondary preregistered outcomes showed no group differences our exploratory analyses provide some evidence for impacts on children's alpha power during the preschool years, although this evidence needs further investigation and replication.