Midday naps may be an important tool to help preschool-age children learn, a new study shows.

That's important information for both parents and for preschools that are feeling pressure to cram more learning into a busy school day, according to the researchers, from the University of Massachusetts Amherst.

The research is published in the current issue of Proceedings of the National Academy of Sciences.

The findings by research psychologist Rebecca Spencer and students Kasey Duclos and Laura Kurdziel show children who took classroom naps were better able to handle a visual-spatial task right after the nap and the next day, compared with children who did not snooze.

It's an issue of significance, they said in a written statement, because both parents and staff at publicly funded preschools have raised questions about the value of napping.

"There is increased public funding for preschools and increased enrollment in preschools due to a surge in research showing the long-term health and educational benefits of early education," Spencer said. "But there was no research on napping so they were a target for elimination in order to make more time for more learning. We offer scientific evidence that the midday naps for preschoolers support the academic goals of early education."

The researchers recruited 40 kids from six preschools in western Massachusetts and taught them a task similar to the game "Memory" in the morning. Children were shown a grid of pictures and told to remember where different pictures were placed on the grid.

The children then participated in both roles in the study: Those who napped and those who skipped the nap. Average nap time was 77 minutes. Memory was tested both right after they learned, in the afternoon after nap time, whether they had a nap or not, and again the next day. Then the students reversed nap or no-nap roles and were tested again.

When children had been kept awake, the accuracy for locating the picture was 65 percent, compared with 75 percent after napping.

"While the children performed about the same immediately after learning in both the nap and wake conditions, the children performed significantly better when they napped, both in the afternoon and the next day," the study authors wrote. "That means that when they miss a nap, the child cannot recover this benefit of sleep with their overnight sleep. It seems that there is an additional benefit of having the sleep occur in close proximity to the learning."

The researchers also brought 14 more children ages 3 to 5 to the sleep lab and recorded their biophysiological changes during naps that averaged 73 minutes. According to the background information accompanying the study, the researchers found correlation between the activity associated with integrated new information and the nap's memory benefit.

"Until now, there was nothing to support teachers who feel that naps can really help young children," Spencer said, adding that "children should not only be given the opportunity, they should be encouraged to sleep by creating an environment which supports sleep."

The study noted, "This nap benefit is greatest for children who nap habitually, regardless of age. Performance losses when nap-deprived are not recovered during subsequent overnight sleep. ... These results suggest that distributed sleep is critical in early learning; when short-term memory stores are limited, memory consolidation must take place frequently."

"This demonstrates very vividly the value of sleep for consolidating memories. Very young children find it quite difficult to retain information over the course of a full day, so in those circumstances, a nap is going to be useful for ensuring that whatever they learn is retained in the longer term," Gareth Gaskell, professor of psychology at York University, told The Guardian.

The research was supported by the National Institutes of Health's National Heart, Lung, and Blood Institute and a UMass Amherst Commonwealth Honors College Grant that was awarded to Duclos.

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