Sleep Development and Memory in Early Childhood

Abstract

Sleep plays a well-established role in learning and memory consolidation in both adults and children. Importantly, sleep changes in substantial ways early in life. This dissertation explores the role sleep plays in learning and memory in early childhood and examines the impact of developmental changes in sleep. The first paper included here describes the changes in sleep that occur from infancy to early childhood. The paper provides an overview of sleep and how it can be measured, the relationship between sleep and memory early in life, and examines a critical point in the development of sleep-wakefulness patterns where children transition from taking regular naps to only sleeping at night. Next, the second contribution, an empirical study, explores the role of napping regularity on the relationship between word learning and sleep in childhood. Between ages 3 and 5 years, children begin to transition out of regular napping. Given the connection between sleep and memory consolidation, how this transition away from napping impacts learning is unclear. In this study, 3.5 to 4.5-year-old habitual and non-habitual nappers are exposed to novel words via a brief, single exposure, and are tested for their memory of the words after a 4-hour delay including either a nap or wakefulness. The third contribution, another empirical study, aims to compare retention profiles for novel words obtained by two different modes of learning—explicit encoding and fast mapping—in 2.5-year-olds. Children’s memory for novel words acquired in these distinct ways are tested after a 24-hour delay including either a nap soon after learning or a period of wakefulness following learning. In all, the goal of this dissertation is to explore sleep early in life and examine its role in memory for novel words.