How early do the experiences that shape who we become actually begin? In this episode of Cracking the Shell on Psychological Science, hosts Mike Dougherty and Joey Barnet talk with Dr. Tracy Riggins, a principal investigator on the Healthy Brain and Child Development (HBCD) Study—the largest long‑term study of early brain development in U.S. history. We explore how researchers are following more than 7,000 families from pregnancy through childhood to understand how biology, environment, and lived experience interact to shape the developing brain. Dr. Riggins explains why the study begins before birth, how infant MRI and EEG work, and what the team is learning about prenatal exposure, risk and resilience, and the protective factors that help children thrive.