He hasn't learned to speak yet, but 7-month-old Clark is about to tell what he knows about language.
\Babies actually learn some things while they're still in the womb, such as the rhythm of their native language,"" said UW psychologist Jenny Saffran. ""By the time they say their first word at about a year, they know an extraordinary amount about how language works.""
Saffran, the director of the Infant Learning Laboratory at UW-Madison's Waisman Center, is conducting research on how infants learn language - from syllables to words to sentences and grammar. She presented her research on at the annual meeting of the American Association for the Advancement of Science on February 17 in Denver, and her findings are being published in Developmental Psychology.
Playing different sound patterns and tracking the attentions spans of her tiny subjects, Saffran determines learning strategies of infants at different ages, and which patterns they learn most easily.
Clark sits on his mother's lap in a soundproof vault with tropical fish painted on the outside and empty on the inside except for a chair. White curtains cover speakers, and a red or orange light glows on three of the four walls as Saffran's graduate assistant, Eric, plays a series of ""nonsense"" words.
Eric watches the monitor and notes how long Clark gazes at the light on the wall that is projecting the sounds. When Clark looks away from the speaker, it means he knows the sound pattern and has lost interest. When he focuses on a speaker, it means he is hearing something new, something he has not learned yet.
This experiment measures how an infant recognizes stress patterns. Saffran has found that babies at six months' age tend to ignore stress patterns, and focus more on sound patterns when learning new words. But at nine months' old they discover that stress occurs on the first syllable of most words, and their learning strategy changes.
Saffran has found that some patterns are easier for infants to learn than others. For instance, sounds in similar acoustic groups, such as sharp, or soft sounds, are easier for infants to learn when they occur together. This may explain how languages evolved.
""No language groups words from dissimilar acoustic groups together,"" Saffran said. ""Why do languages look so similar? Probably because that's what babies can learn more easily.""
Saffran hopes her research will shed more light on how infants acquire language, and importantly, why some children don't acquire language as well as others.
""Ten percent of children with normal IQ's end up with language problems, and no one knows why,"" Saffran said. I hope we can eventually apply this research to kids whose language-learning process has gone less smoothly.""
But Saffran says these applications are way down the road. Her current focus is discovering the process and strategies infants use to learn language.
""Right now we know so little about the infant's mind and how it works,"" Saffran said. ""It's exciting to figure out what's going on in there.""
