Heather Bortfeld is Professor of Psychological Sciences and Cognitive and Information Sciences at the University of California, Merced. She has been a pioneer in the development of functional near-infrared spectroscopy (fNIRS) as a tool for measuring changes in brain activity in infants and toddlers as they engage with the world around them. She is currently the Emmett, Bernice, and Carlston Cunningham Endowed Chair in Cognitive Development at UC Merced, and an elected Fellow of the Association for Psychological Sciences. Silvia A. Bunge is a Professor of Psychology at the University of California, Berkeley, and directs the Building Blocks of Cognition Laboratory, which draws from the fields of cognitive neuroscience, developmental psychology, and education research. She studies the development of higher-level cognitive abilities, how they are shaped by experience, and how they support academic success. She is an elected Fellow of the Association for Psychological Sciences and the recipient of a Jacobs Foundation Advanced Career Research Fellowship and an Alexander von Humboldt Research Award.