Exploring Developmental Connections: Sleep Patterns, Self-Locomotion, and Vocabulary Growth in Early Childhood

Current research indicates likely developmental connections between the evolution of sleep patterns, motor skills progression, and the expansion of vocabulary. These connections are grounded in the well-established role of sleep in memory and learning, as well as in the cascading effects on language development of the acquisition of new motor skills. However, no study has so far undertaken a comprehensive and systematic examination of these connections or explored their developmental trajectory over time. Yet understanding vocabulary development depends on considering development in the sleep regulation and motor domains, to provide a biologically grounded explanation of how early lexicons are built and strengthened. This study investigates the links between vocabulary growth and two significant changes occurring over the first 2 years of life: self-initiated locomotion and the consolidation of overnight sleep. Our results reveal mutual associations between these domains, which tend to emerge during periods of marked developmental change in language, motor skills, and sleep patterns regulation. Moreover, these associations were observed to change over time, suggesting dynamic interconnections between these developmental domains. Our findings point toward the importance of investigating vocabulary development from a dynamic systems perspective, as the product of continuous interactions between cognition, the body and the environment.