July 2010

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Infants Can Learn While Sleeping

Snoozing newborns may have more going on than you think. Even when asleep, babies are capable of a simple form of learning, a new study shows.

Since newborns spend most of their time sleeping, scientists have long wondered if some learning occurs during slumber. Researchers recently discovered that newborns can process some outside information while they’re asleep—for example, sounds of speech.

To see whether newborns could learn about relationships between events while sleeping, NIH-funded researchers studied 1- or 2-day-old infants. The scientists repeatedly played a brief musical tone followed by a faint puff of air to each sleeping infant’s eyelids. The babies scrunched their faces when they felt the puff. After several repeats, the researchers played a tone without the air puff.

After about 20 minutes, the tones made most infants (24 out of 26) scrunch their faces even without the puff of air. Infants who were exposed to random, unpaired tones and air puffs didn’t squeeze their eyelids in response to isolated tones.

In addition, after the babies had been exposed to the paired tones and air puffs, their brain wave activity showed some changes when the tone sounded. The researchers interpret this as further evidence that the sleeping infants had learned to link the tone to the air puff.

The researchers say that this is the first study to demonstrate that newborn infants are capable of learning about relationships between events while asleep. It’s still unknown whether this quality is unique to infants or could also occur in older children and adults.