We take a whole-child approach to understanding development, recognizing that infants simultaneously develop across language, cognitive, motor, emotional, and social domains. And so, it’s important to understand how skills in one area of development affect skills in other domains, and cascade over developmental time. For example, we might ask how infants’ transition to walking changes how infants interact with people and objects in their environment; or how the acquisition of language concepts such as boy and girl shapes infants’ gendered play; or how early social experiences snowball over time to influence school readiness and learning outcomes years later.