Daytime naps help improve learning in preschool children by significantly enhancing their memories, according to a study released Monday from sleep researchers at the University of Massachusetts, Amherst.
Research psychologist Rebecca Spencer and her team studied the effects of daytime naps on 40 preschool children by measuring their performance on a simple memory game. In the morning, students played a visual-spatial game in which they must try to remember the locations of different images and were then either kept awake during their regular naptime or encouraged to sleep. When the students were re-tested in the afternoon, Spencer and her colleagues found that when the children skipped their naps, they recalled 10 percent fewer of the test locations than when they napped.
"We're providing a simple proof that naps are really critical to the day, and scientific evidence that's needed to protect that as part of the day," Spencer says.
The team also found there was a connection between those students who performed better on the memory tests and the amount of memories that were actively processed during the nap. The researchers monitored the brain activity of 14 children in a sleep lab and found that those who performed better also had higher levels of activity associated with processing memories as they napped. This activity, Spencer says, appeared to be more important than the length of the child's nap.
"Most important is just that the nap exists at all," Spencer says.
To determine whether nighttime sleep affected the students' memory recall, the researchers also tested students the next morning and saw similar results, meaning the children cannot "make up" on missed sleep time.
In his State of the Union address in February, President Barack Obama pledged to push for universal, publicly-funded preschool for all children, and outlined a $75 billion plan to do so during the next 10 years in his 2014 budget. The proposal drew on research that shows children who attend preschool have better mental and physical health outcomes later in life.
But due to that push, Spencer says, some educators are adding academic and curricular activities in an attempt to further enhance those outcomes, sometimes at the expense of children's rest time. Because up until now, there has been no research on the benefits of napping, it has been a target for elimination in order to make more time for more learning, Spencer says.
"What we see in some of the classrooms is there's less and less interest in the nap," Spencer says. "We also see just pressure on these classrooms to put so much other stuff into their day ... which means at the very least, the opportunity [students] have to nap is getting shorter and shorter."
States also have loose guidelines for the length of children's rest times and what they are allowed to do during that time – whether they are required to rest, or if they can participate in other "quiet time" activities, such as reading. In South Carolina, for example, the state mandates that "napping or resting period shall be appropriate to the individual needs of the child," but gives no specification as to what portion of the day is dedicated to resting.
With less strict guidelines, Spencer says it is also important that teachers encourage students to nap during the day because the children appeared to have the best outcomes when their naps occurred closer in time to their instruction. Additionally, in children, the hippocampus (the part of the brain in which memories are stored) is "rather small and immature, with only so much space to take information in," Spencer says. This is why it's important for children to nap and empty out that space before attempting to take in more information.
"So when they skip a nap, you're just piling more and more into there that it just doesn't have a capacity for," Spencer says.