Newborns Learn Vowels While Sleeping
Brain scans reveal that learning lasts
WEDNESDAY, Feb. 6, 2002 (HealthDayNews) -- Newborns spend most of their day asleep, but their minds are still active, says a new study that shows they can learn to tell the difference between various spoken sounds while they snooze.
Researchers suggest they're able to do this because of a pattern of sleep unique to infants.
"It's been suspected that infants could learn in their sleep, but it's nice to have a very clear demonstration," says Janet F. Werker, an expert on childhood language acquisition at the University of British Columbia in Vancouver. The study appears in tomorrow's issue of the journal Nature.
Lead investigator Marie Cheour is the head of the Laboratory of Language and the Developing Brain Laboratory at the University of Turku in Finland. She and her colleagues enlisted the help of 15 healthy, full-term newborns still in the hospital following their birth.
Cheour's team brought the babies to their laboratory during the evening, where they hooked up each infant to an electroencephalograph (EEG), a noninvasive device used to measure brain waves.
Over the course of the evening, while the babies were asleep, the researchers played standard and slightly deviated vowel sounds while the EEG recorded their brain waves. When the babies woke up, they received formula and whatever attention they needed, and the sounds began again once they went back to sleep.
That night, half of the infants were returned to their mothers, while the remaining children stayed for the entire evening.
The next morning, all of the babies again were part of the same EEG experiment. From the EEG readings, Cheour's team could determine whether the babies' brains were discriminating between different speech sounds.
"We learned that all the children whom we trained to discriminate between those speech sounds really did learn it," says Cheour. "Those who spent the night with their mothers didn't."
To find out if the effects lasted, the babies returned to the laboratory one day later and repeated the test.
"Even the next evening, the children continued to be able to discriminate those speech sounds," says Cheour. "I was surprised that it happened so quickly."
Although it's not clear when children stop learning while sleeping, Cheour says it's likely they lose the ability very quickly.
"Infant sleep is very different from ours," says Cheour, explaining that they spend much more time in the active, dream-stage sleep that has been linked to brain maturation and development.
It's not yet clear whether infants can learn to distinguish between other speech sounds, such as consonants or even musical notes, says Cheour.
Werker says states of consciousness differ between infants and older children or adults.
"We know that learning is state-dependent, and that infants are less able to take in information when they're fussy and crying," she says. "Very young infants are not in a quiet, alert state very much of the time. If that were the only time that they could learn, they wouldn't have much opportunity to be learning about the world around them."
Werker adds this ability lasts only for the first few weeks of life: "This demonstration of learning during sleeping is probably restricted to very young infants."
Cheour stresses her goal is not to create some sort of "super baby" who can speak multiple languages. Instead, she says, she interested in using this technique as a tool to help infants at risk for learning problems.
"We know, for example, that if their parents or siblings have learning problems, there's quite a big risk that infants will develop learning problems later on," she says.
What To Do
You can learn about different speech and language developmental milestones from the National Institute on Deafness and Other Communication Disorders.