Sleep plays a vital role in the early learning and development of babies and young children, a study has found.
Infants who nap are better able to apply lessons learned to new skills, while sleeping appears to help pre-school toddlers retain learned knowledge.
US researchers looked at the ability of young children to recognise something similar but not identical to what they have learned and apply it to a new situation.
Known as “generalisation”, language examples include recognising the letter “A” in different fonts, understanding a word regardless of who speaks it, or spotting a grammatical pattern in a sentence never heard before.
“Sleep is essential for extending learning to new examples,” said study leader Dr Rebecca Gomez, from the University of Arizona.
“Naps soon after learning appear to be particularly important for generalisation of knowledge in infants and pre-schoolers.”
One experiment involved playing an artificial “training language ” to year-old infants over loudspeakers. The babies were then tested to see if they recognised new vocabulary straight after either taking a nap or staying awake.
Those who napped were better able to absorb the language rules and apply them to recognising entirely new sentences in the language.
Their performance was assessed by timing how long they spent with their heads turned to listen to correctly versus incorrectly structured sentences.
Pre-schoolers did not form generalisations during sleep in the same way. However, naps helped them retain generalisations formed earlier, after an interval of wakefulness.
The research was presented at the annual meeting of the Cognitive Neuroscience Society in Boston, US.
Dr Susanne Diekelmann, from the University of Tubingen in Germany, who chaired a symposium on sleep at the conference, said: “Sleep is a highly selective state that preferentially strengthens memories that are relevant for our future behaviour.
“Sleep can also abstract general rules from single experiences, which helps us to deal more efficiently with similar situations in the future.”