New Research Shows Link Between Brain Growth And Nap Transitions In Young Children

An important part of human development is nap transition—the change from multiple sleep cycles in a day to an overnight sleep cycle. Infants sleep for hours a day in multiple bouts (polyphasic). Toddlers and preschoolers transition to one or two daytime naps of lesser duration, along with an overnight sleep cycle. Adults mostly have a monophasic sleep cycle, just sleeping overnight. It might seem like these transitions vary with age, but this might not be the case.

In their new study titled ‘Contributions of memory and brain development to the bioregulation of naps and nap transitions in early childhood,’ published in Proceedings of the National Academy of Sciences, authors Rebecca Spencer and Tracy Riggins said that nap transitions are determined by a child’s memory and brain development, and not so much by their age. This is probably why some preschoolers need a nap every day, while some grow out of the habit earlier, they added. Spencer is a neuroscientist at the University of Massachusetts Amherst while Riggins is a University of Maryland child psychologist.

The role of the hippocampus

In their study, Spencer and Riggins focused on the hippocampus, a complex part of the brain considered to be a short-term location for memories before they move to the cortex (responsible for thinking and reasoning). Naps help in processing memories in the hippocampus, said Spencer. When a child’s hippocampus reaches its maximum limit of memories, they experience 'sleep pressure' or the need to take a nap. When they nap, memories move to the cortex, thereby freeing up space in the hippocampus. As the hippocampus develops, the child is able to store more memories, and they eventually transition out of naps. The rate of development of the hippocampus varied with each child said the researchers.

The researchers taught children a visuospatial task. The task was first taught before the children’s afternoon nap, and then again before an equal interval of time when they were awake. Children who had taken a nap were able to recall from memory better than the others who had skipped their nap. The same was tried with children who habitually napped and those who didn’t. It was found that memory consolidation “did not differ for habitually and non-habitually napping children; naps protected memories regardless of nap habituality.” But interestingly enough, the research confirmed that a missed nap could cause more damage to the memory of habitually napping children, compared with those who didn’t nap habitually. This was because nonhabitual nappers had a better-developed hippocampus, and thus, better memory.

Naps are important for learning

The authors stressed the importance of naps for young children. When children nap, their memory is seen to improve, and this in turn helps them with learning. The researchers have urged parents to understand the needs of their children and not force habitual nappers to skip a nap or two, because forced nap transitions can lead to suboptimal memory and learning.

According to the researchers, the study will help parents and caregivers understand that some children might need a nap more than others and that it will only enhance their brain function. So, next time you think about letting your child skip their midday nap, think again!