Brain picks up language early, powerfully From the Science & Technology Desk
Published 8/29/2002 2:05 PM
Petitto and Holowka describe their findings in Aug. 30 issue of the journal
Science. The research by Mehler and colleagues is published online on the
Aug. 29 Science Web site.-- (Reported by Charles Choi, UPI Science News, in New York) Copyright © 2002 United Press International
HANOVER, N.H., Aug. 29 (UPI) -- Canadian and U.S. researchers have found each bite-sized syllable of nascent speech uttered by infants originates straight from the brain's language centers, revealing these bio-circuits go online much earlier than thought.
For decades, many scientists had assumed when babies babbled, they merely were exercising their lips, tongue and jaws for the day when they started talking. Instead, the brain's initiation of speech is "up and running much earlier than we ever knew," researcher Laura-Ann Petitto, a cognitive
neuroscientist at Dartmouth College, told United Press International.
This suggests doctors one day may detect potential language problems in very young babies "before they even utter their first word," Petitto said.
Meanwhile, research from Italy and France has found learning a language
requires complex statistics and algebra-like thinking more intense than
previously reported.
"This research contributes to our understanding of the property that is most
characteristic of the human species -- language," said researcher Jacques
Mehler, a cognitive psychologist at the International School for Advanced
Studies in Trieste, Italy. "It may explain why we are able to acquire
grammatical systems while other organisms are not, even when they are our close ancestors."
Human language circuits are located on the left side of the brain, which
also controls the right side of the body. Petitto and colleague Siobhan
Holowka at McGill University in Montreal reasoned if a baby's mouth pulled
toward its right while babbling, that meant the infant's linguistic
machinery was activating.
They analyzed video clips of 10 babies from 5-to-12 months old as they
babbled syllables such as "da," made non-babbling sounds such as cooing and gurgling, or simply smiled. Half the babies studied were learning English
while the other five learned French, to minimize any language-specific bias.
Petitto and Holowka found babies' mouths did indeed veer right more often
during babbling. In addition, the babies' mouths remained symmetrical during
non-babbling, revealing such activity did not draw preferentially from
either side of the brain. Curious, but the mouths leaned left while smiling,
which Petitto suggests may happen because emotion-related activity is
related to the brain's right half.
"The main contribution of this paper is to confirm that babbling is a
definite precursor to language," said neuroscientist Joy Hirsch of Columbia
University in New York. "That's been a question for a long time, and this is
pretty definitive evidence that it is so. This really suggests that neural
foundation for language is present well before language is produced."
Through experiments in which about 100 French-speaking adults were taught a made-up language, Mehler and his colleagues discovered insights into how words are identified from continuous streams of sound, a process apparently involving statistical computation. Their experiments showed people are capable of statistical thinking that is "much more powerful" than previously thought, capable of analyzing not only adjacent syllables but also
non-neighboring syllables to identify words, Mehler said.
In addition, although many scientists have suggested only statistical
thinking was necessary to acquire language, Mehler provided evidence that
people seeking to understand complex grammatical structures appeared to
require algebra-like thinking, which was needed to identify grammatical
patterns and apply them to new examples.
"This research supports the idea of the mind as a Swiss army knife, filled
with different tools for solving different kinds of tasks," cognitive
scientist Gary Marcus of New York University told UPI, adding that although
animals are known to demonstrate statistical thinking, "this shows we may
have a other tools in our toolkit for learning as well."
Mehler said a more realistic model of how people acquire language eventually could help understand and treat aphasia, a form of brain damage that removes the ability to comprehend language.
Petitto and Holowka describe their findings in Aug. 30 issue of the journal
Science. The research by Mehler and colleagues is published online on the
Aug. 29 Science Web site.--
(Reported by Charles Choi, UPI Science News, in New York)
Copyright © 2002 United Press International
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