Newborn babies develop so quickly because they’re learning even when they’re asleep, it seems. A newborn’s brain is continually adapting and adjusting even when they’re napping, researchers say.

Tests on one-day-old and two-day-old babies have suggested newborns act as “data sponges”, absorbing info from their surrounding world non-stop, reports the Telegraph.

The tests involved newborn babies being played a tune, which was followed by a gentle puff of air on their eyelids. Around 20 minutes on, 24 of the 26 babies involved had learnt to anticipate the air puff, squeezing shut their eyes. The babies’ brainwaves also changed, the researchers from the University of Florida found.

"We found a basic form of learning in sleeping newborns, a type of learning that may not be seen in sleeping adults,” explained psychologist Dana Byrd.

"They are better learners, better 'data sponges' than we knew. While past studies find this type of learning can occur in infants who are awake, this is the first study to document it in their most frequent state, while they are asleep.

"Newborn infants' sleep patterns are quite different to those of older children or adults in that they show more active sleep where heart and breathing rates are very changeable.

"It may be this sleep state is more amenable to experiencing the world in a way that facilitates learning."

Dana said the findings might be useful for identifying babies that aren’t developing as anticipated, such as those at risk of autism or dyslexia.