Why do some 4- and 5-year-olds still nap like clockwork every afternoon, while other preschoolers start giving up habitual napping at age 3?

It’s a matter many parents little question ponder and one which a University of Massachusetts Amherst sleep scientist has been considering for years. Now, in a paper published Monday, Oct. 24, in a special sleep issue of Proceedings of the National Academy of Sciences, lead creator Rebecca Spencer describes a latest theory about why and when young children transition out of naps. It isn’t about age as much because the brain.

“This overarching theory is predicated on data that we have published over the past couple of years; it’s about putting the pieces together,” says Spencer, professor of psychological and brain sciences, who collaborated with co-author Tracy Riggins, a University of Maryland child psychologist specializing in memory development. “Collectively, we offer support for a relation between nap transitions and underlying memory and brain development. We’re saying it is a critical time of development within the brain and sleep has something to do with it.”

The novel theory, which supports the practice of providing the chance for all preschoolers and pre-kindergarteners to nap, connects bioregulatory mechanisms underlying nap transitions, specializing in the hippocampus – the memory area of the brain. Spencer notes that it could seem counterintuitive for young kids to desert habitual naps. “When little kids are napping, they consolidate emotional and declarative memories, so you then ask yourself, when that is such a very important time of learning, why would they transition out of napping if napping helps learning? Why not only keep napping?”

Previous research by Spencer and Riggins showed “there is a difference in the event of the hippocampus for teenagers who nap and people who have transitioned out of naps,” Spencer says.

The hippocampus is the short-term location for memories before they move to long-term storage within the cortex. “The naps are serving the job of processing memories,” Spencer explains. When young kid’s immature hippocampus reaches its limit of memories that could be stored without “interference,” or forgetting, kids experience heightened “sleep pressure.” Researchers take a look at EEG slow-wave activity, a neurobiological marker within the brain waves recorded during sleep, to measure the buildup of homeostatic sleep pressure.

Napping allows memories to maneuver to the cortex, freeing space for more information to be stored within the hippocampus. Spencer likens the developing hippocampus to a bucket of various size.

When the hippocampus is inefficient, it’s like having a small bucket. Your bucket goes to refill faster and overflow, and a few memories will spill out and be forgotten. That is what we predict happens with the youngsters which are still napping. Their hippocampus is less mature, they usually have to empty that bucket more incessantly.”

Rebecca Spencer, Lead Creator

When the hippocampus is more developed, kids can transition away from taking naps because their hippocampus has matured to some extent that their “bucket” is not going to overflow. They will hold memories until the top of the day, when overnight sleep can process information from the hippocampus to the cortex, the researchers posit.

Spencer says the growing evidence highlights the importance of providing all young children with the chance to nap. “A few of them still need it; others may not need it but in the event that they take it, we all know that it is going to profit their learning, and we all know that learning is what underlies early education.”

What’s needed next to advance the speculation is longitudinal research that follows children over time to evaluate sleep physiology, structural and functional development, and memory changes across nap transitions.

Additional scientific evidence “would help parents and providers appreciate that nap transitions can’t be determined by age, and the chance to nap needs to be protected for people who need it.”

In the long run, Spencer says, researchers may give you the option to develop a cognitive measure of memory, perhaps giving kids a sure bet to find out in the event that they’ve crossed the edge of needing regular naps.

For now, nonetheless, the evidence supports the vital role napping plays in young kid’s growth. Forced transitions out of napping “may lead to suboptimal learning and memory,” Spencer says.

As well as, the brand new framework the researchers developed “could be used to judge multiple untested predictions from the sector of sleep science and, ultimately, yield science-based guidelines and policies regarding napping in childcare and early education settings.”

Source:

University of Massachusetts Amherst

Journal reference:

Spencer, R.M.C., et al. (2022) Contributions of memory and brain development to the bioregulation of naps and nap transitions in early childhood. PNAS. doi.org/10.1073/pnas.2123415119.