As adorable newborn babies are when they sleep, it can sometimes be baffling that they spend so much of their days in this state – and not just because that means they don’t spend enough of their nights asleep. They don’t seem to have done enough work to be exhausted, and they have so much to learn about the world that sleep seems counterproductive…unless they can learn in their sleep.
This was the idea of researchers who took on the fun task of tucking sleeping newborns between two speakers, a cap of electrodes on theirs heads, and playing them simple tones. For some newborns, the tones predicted a gentle puff of air to the eyelid (one you may have received yourself at a healthy eye exam); for others, the tones and puffs occurred randomly. It took just 20 puffs of air after a tone for the sleeping babies to start moving theirs eyes when the tone played, in anticipation of the puff. These eye twitches were paired with a subtle shift in brain activity, indicating that the tone was processed by the sleeping brain.
A twitch after a tone is not quite enough to suggest parents should rush out and buy Mozart or French instruction CDs for their babies. However, it does tell us that sleeping babies are far from oblivious to the world around them; they could be picking up even more complex cues than tone=puff, perhaps some important features of language. So parents can hope for their newborn to fall asleep guilt-free, because the learning doesn’t stop when their eyelids close.
Fifer, W., Byrd, D., Kaku, M., Eigsti, I., Isler, J., Grose-Fifer, J., Tarullo, A., & Balsam, P. (2010). Newborn infants learn during sleep Proceedings of the National Academy of Sciences, 107 (22), 10320-10323 DOI: 10.1073/pnas.1005061107