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Babies Learn To Talk By Reading Lips, New Research Suggests

Babytalk

LAURAN NEERGAARD   01/16/12 02:55 PM ET  AP

WASHINGTON — Babies don't learn to talk just from hearing sounds. New research suggests they're lip-readers too.

It happens during that magical stage when a baby's babbling gradually changes from gibberish into syllables and eventually into that first "mama" or "dada."

Florida scientists discovered that starting around age 6 months, babies begin shifting from the intent eye gaze of early infancy to studying mouths when people talk to them.

"The baby in order to imitate you has to figure out how to shape their lips to make that particular sound they're hearing," explains developmental psychologist David Lewkowicz of Florida Atlantic University, who led the study being published Monday. "It's an incredibly complex process."

Apparently it doesn't take them too long to absorb the movements that match basic sounds. By their first birthdays, babies start shifting back to look you in the eye again – unless they hear the unfamiliar sounds of a foreign language. Then, they stick with lip-reading a bit longer.

"It's a pretty intriguing finding," says University of Iowa psychology professor Bob McMurray, who also studies speech development. The babies "know what they need to know about, and they're able to deploy their attention to what's important at that point in development."

The new research appears in this week's issue of the Proceedings of the National Academy of Sciences. It offers more evidence that quality face-time with your tot is very important for speech development – more than, say, turning on the latest baby DVD.

It also begs the question of whether babies who turn out to have developmental disorders, including autism, learn to speak the same way, or if they show differences that just might provide an early warning sign.

Unraveling how babies learn to speak isn't merely a curiosity. Neuroscientists want to know how to encourage that process, especially if it doesn't seem to be happening on time. Plus, it helps them understand how the brain wires itself early in life for learning all kinds of things.

Those coos of early infancy start changing around age 6 months, growing into the syllables of the baby's native language until the first word emerges, usually just before age 1.

A lot of research has centered on the audio side. That sing-song speech that parents intuitively use? Scientists know the pitch attracts babies' attention, and the rhythm exaggerates key sounds. Other studies have shown that babies who are best at distinguishing between vowel sounds like "ah" and "ee" shortly before their first birthday wind up with better vocabularies and pre-reading skills by kindergarten.

But scientists have long known that babies also look to speakers' faces for important social cues about what they're hearing. Just like adults, they're drawn to the eyes, which convey important nonverbal messages like the emotion connected to words and where to direct attention.

Lewkowicz went a step further, wondering whether babies look to the lips for cues as well, sort of like how adults lip-read to decipher what someone's saying at a noisy party.

So he and doctoral student Amy Hansen-Tift tested nearly 180 babies, groups of them at ages 4, 6, 8, 10 and 12 months.

How? They showed videos of a woman speaking in English or Spanish to babies of English speakers. A gadget mounted on a soft headband tracked where each baby was focusing his or her gaze and for how long.

They found a dramatic shift in attention: When the speaker used English, the 4-month-olds gazed mostly into her eyes. The 6-month-olds spent equal amounts of time looking at the eyes and the mouth. The 8- and 10-month-olds studied mostly the mouth.

At 12 months, attention started shifting back toward the speaker's eyes.

It makes sense that at 6 months, babies begin observing lip movement, Lewkowicz says, because that's about the time babies' brains gain the ability to control their attention rather than automatically look toward noise.

But what happened when these babies accustomed to English heard Spanish? The 12-month-olds studied the mouth longer, just like younger babies. They needed the extra information to decipher the unfamiliar sounds.

That fits with research into bilingualism that shows babies' brains fine-tune themselves to start distinguishing the sounds of their native language over other languages in the first year of life. That's one reason it's easier for babies to become bilingual than older children or adults.

But the continued lip-reading shows the 1-year-olds clearly still "are primed for learning," McMurray says.

Babies are so hard to study that this is "a fairly heroic data set," says Duke University cognitive neuroscientist Greg Appelbaum, who found the research so compelling that he wants to know more.

Are the babies who start to shift their gaze back to the eyes a bit earlier better learners, or impatient to their own detriment? What happens with a foreign language after 12 months?

Lewkowicz is continuing his studies of typically developing babies. He theorizes that there may be different patterns in children at risk of autism, something autism experts caution would be hard to prove.

___

EDITOR'S NOTE – Lauran Neergaard covers health and medical issues for The Associated Press in Washington.

Click through this gallery of seven more amazing things you probably didn't know about babies:
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  • Their Baby Cuteness Doesn't Predict Adult Attractiveness

    A study published in the journal <em>Infant Behavior & Development</em> revealed that the standard "<a href="http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCQQtwIwAA&url=http%3A%2F%2Fwww.youtube.com%2Fwatch?v%3DXTV8bOv3Jhs&ei=0uLBToKrMuPu0gHkmNH0BA&usg=AFQjCNFtutJJhlTFZJ2fm-cmsDo46XMpzw" target="_hplink">You Must Have Been a Beautiful Baby</a>" has little to do with reality. When 253 college students were asked to rank photos of the same individuals as infants and young adults (without being told who was who), there was <a href="http://bodyodd.nbcnews.com/_news/2011/08/31/7542626-must-have-been-a-beautiful-baby-maybe-not" target="_blank">no relationship between how cute the students found the babies and how attractive they found the grown-ups</a>.

  • They're Good At Sharing

    No, really, it's true. It doesn't matter how many times you've heard the shout "Mine!" -- research shows babies can sense fairness at 15 months. During one study at the <a href="http://www.washington.edu/news/articles/babies-show-sense-of-fairness-altruism-as-early-as-15-months-1" target="_hplink">University of Washington</a>, 47 babies observed videos of an experimenter distributing milk and crackers to two people. When one recipient received more food than the other, the babies paid more attention. That means they had expected a fair distribution. The researchers also found that babies who did notice unfairness were more likely to share their own toys.

  • They Read Minds

    OK, so they're not exactly psychic. But a <a href="http://www.sciencedaily.com/releases/2011/11/111101130204.htm" target="_hplink">recent study</a> from the University of Missouri found that babies just 10 months old are starting to follow the thought processes of others. Yuyan Luo, an associate professor of developmental psychology who conducted the study, tells The Huffington Post, "Babies, like adults, when they see something for the first time -- when something is surprising -- they look for a long time. It shows [they recognize] something is inconsistent." It's called the "violation of expectation," she explained. When babies are surprised by something or notice something unexpected has happened, they tend to gaze at that thing longer. In Luo's research, babies watched actors consistently choose object A (such as a block or a cylinder) over object B. When an actor then switched to object B, the babies stared for about five to six seconds longer, meaning they recognized the change in preference.

  • They're A Little Bit Racist

    Don't judge a book by its cover. Treat all people the same. We're all equals. These are sentiments parents strive to teach their kids from a very young age. And they should. Starting, like, immediately. Researchers at the University of Sheffield in the United Kingdom found that babies at three months <a href="http://www.world-science.net/exclusives/060212_racefrm2.htm" target="_hplink">begin showing a preference for the faces of people of their own race</a>. But not all hope for equality is lost. The same study showed that babies who are exposed to people of all different races are less likely to develop bias at such an early age.

  • The Rhythm Is Gonna Get Them

    Researchers from Brigham Young University found that five-month-old babies can <a href=" http://news.byu.edu/archive08-oct-babymusic.aspx" target="_hplink">identify an upbeat song as being different from a series of sad, slow songs</a>. In other words, they are happy. They know it. They will clap their hands. Or stare longer, as the case may be. The experimenters showed babies an emotionless face while music played. When they played a new sad song, the babies looked away. When the music pepped up, the babies stared for three to four seconds longer.

  • They Can Tell The Good Guy From The Bad Guy

    Babies have a sense of morality at six months old, <a href="http://www.dailymail.co.uk/news/article-1275574/Babies-know-difference-good-evil-months-study-reveals.html" target="_hplink">say Yale researchers</a>. During the Yale study, babies watched a puppet show in which a wooden shape with eyes tried to climb a hill over and over again. Sometimes a second puppet helped him up the hill, and other times a third puppet pushed him down. After watching the act several times, the babies were presented with both puppets. They showed a clear preference for the good characters over the bad ones by reaching to play with the good puppet.

  • They Can Read Lips ... Kind Of

    Dr. Janet Werker of the University of British Columbia, who studies how babies perceive language, found that if a mother spoke two languages while pregnant, her infant could <a href="http://www.livescience.com/13016-bilingual-babies-brain-language-learning.html" target="_hplink">recognize the difference</a> between the two. And they don't even have to be spoken out loud. Werker's research found that infants four to six months old can <a href="http://www.nytimes.com/2011/10/11/health/views/11klass.html" target="_hplink">visually discriminate two languages</a> when watching muted videos of someone speaking both.

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Filed by Jessica Samakow  |