Parents, want your kids to learn better? Let them take an afternoon nap!

Taking an hour-long nap during the day can boost learning in preschool children by improving their memory, a new first-of-its-kind study has found.

Researchers at the University of Massachusetts Amherst found that a nap helped children better remember pre-school lessons.

Research psychologist Rebecca Spencer, with students Kasey Duclos and Laura Kurdziel, said their results suggest naps are critical for memory consolidation and early learning, based on their study of preschool children.

"Essentially we are the first to report evidence that naps are important for preschool children. Our study shows that naps help the kids better remember what they are learning in preschool," Spencer said.

For the study, Spencer and colleagues recruited 40 children from six preschools across western Massachusetts.

The researchers taught children a visual-spatial task similar to the game 'Memory' in the mornings. In this game, children see a grid of pictures and have to remember where different pictures are located. Each child participated in two conditions.

In one condition, the children were encouraged to nap during their regular classroom nap opportunity.

Naps lasted an average of 77 minutes as recorded by observers in the classroom. In the second condition, children were kept awake for the same amount of time.

Memory for the game was tested after the nap and wake conditions and again the following day to see whether nighttime sleep affected performance.

Children forgot significantly more item locations on the memory test when they had not taken a nap (65 per cent accuracy), compared to when they did nap (75 per cent accuracy).

Thus following a nap, children recalled 10 per cent more of the test locations than when they had been kept awake.

"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," researchers concluded.

"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," they said.

The study was published in the journal Proceedings of the National Academy of Sciences.