Researchers at Columbia University exposed sleeping 1-to-2 day old infants to tiny puffs of air directed at the eyelid in conjunction with a tone. The study was painless for the sleeping babies. The babies were well-fed before the study began to guarantee they would rest peacefully. To measure the results the scientists put an infant sized EEG net on their head to monitor their brain activity. In the experimental group, the sound reliably preceded a puff of air, while in the control group tones and puffs of air occurred at random. In less than half an hour, the infants in the experimental group exhibited an increase in conditioned eye movement response—meaning they squeezed their eyes together after just hearing the tone. The sleeping infants learned to associate the sound with the air. According to the researchers the “current experiment demonstrates that newborn infants are capable of learning about relationships between stimuli while asleep.”
Although learning processes in awake newborns are well documented, this is one of the first studies to indicate babies can interpret information while asleep. Since newborns can snooze up to 16 hours a day (sometimes more), the researchers hypothesize that learning while sleeping may be an adaptive trait necessary for survival at an early age. The research team, whose paper was published in the Proceedings of the National Academy of Sciences, reported the greatest activity seen in the frontal areas of the babies brains, according to EEG data, which may indicate the updating of incomplete memories.
It is unclear whether adults learn while sleeping, though most researchers believe they do not, or at least not in the same way. However, sleep does play a role in our ability to learn throughout waking hours and getting shut-eye is necessary to consolidate memories and retain new information. Similar mechanisms may be at play for newborns, but because their sleep patterns are so different from older children and adults, the lines between learning and sleeping could be blurred.
Besides helping to elucidate how babies learn and process outside stimuli, the research suggests that eyelid conditioning may be a non-invasive way to identify children with learning difficulties. Eyelid conditioning works in conjunction with the cerebellum, and certain disorders, like dyslexia, autism, and attention deficit hyperactivity disorder, are associated with deficits in this area.