From Reuters:
“Study of polyglots offers
insight on brain's language processing”
While most people speak only one
language or perhaps two, some are proficient in many. These people are called
polyglots. And they are helping to provide insight into how the brain deals
with language, the principal method of human communication. In a new study
involving a group of polyglots, the brain activity of the participants was
monitored using a method called functional magnetic resonance imaging as they
listened to passages read in various languages. With one intriguing exception,
activity increased in the areas of the cerebral cortex involved in the brain's
language-processing network when these polyglots - who spoke between five and
54 languages - heard languages in which they were the most proficient compared
to ones of lesser or no proficiency. "We think this is because when you
process a language that you know well, you can engage the full suite of
linguistic operations - the operations that the language system in your brain
supports," said Massachusetts Institute of Technology neuroscientist
Evelina Fedorenko, a member of MIT's McGovern Institute for Brain Research and
senior author of the study published on Monday in the journal Cerebral Cortex,
opens new tab. "You can access all the word meanings from memory, you can
build phrases and clauses out of the individual words, and you can access
complex, sentence-level meanings," Fedorenko added.
But an exception caught the
attention of the researchers. In many of the participants, listening to their
native language elicited a lesser brain response compared to hearing other
languages they knew - on average down about 25%. And in some of the polyglots,
listening to their native language activated only a part of the brain's
language network, not the whole thing. "Polyglots become experts in their
native language from the point of view of efficiency of neural processes that
are required to process it. Therefore, the language network in the brain does
not activate as much when they do native versus non-native language
processing," said neuroscientist and study co-lead author Olessia
Jouravlev of Carleton University in Canada. "One's native language may
hold a privileged status, at least in this population," Fedorenko added,
referring to the study's polyglot participants.
The brain's language network
involves a few areas situated in its frontal and temporal lobes. "The
language network supports comprehension and production across modalities -
spoken, written, signed, etc. - and helps us encode our thoughts into word
sequences and decode others' thoughts from their utterances," Fedorenko
said. Study co-lead author Saima Malik-Moraleda, a doctoral student at the
Harvard/MIT Program in Speech and Hearing Bioscience and Technology, said the
findings suggest that the distillation of meaning governs brain response to
language. "The more meaning you can extract from the language input you
are receiving, the greater the response in language regions - except for the
native language, presumably because the speaker is more efficient in extracting
meaning from the linguistic input," Malik-Moraleda said.
The 34 study participants, 20 men
and 14 women, ranged in age from 19 to 71. Twenty-one were native English
speakers, with the rest native speakers of French, Russian, Spanish, Dutch,
German, Hungarian and Mandarin Chinese. Their brain activity was monitored when
they listened to recordings of passages in eight languages: their native
language, three others in which they were highly proficient, moderately
proficient and minimally proficient, and then four they did not know. Half
heard recordings of Lewis Carroll's "Alice in Wonderland." The other
half heard recordings of biblical stories. The lesser brain response to hearing
one's native language was most pronounced among the study participants who
heard the biblical stories - linguistically simpler, according to Fedorenko,
than Carroll's writing. "A lot of work in language research,"
Fedorenko said, "has focused on individuals with linguistic difficulties -
developmental or acquired. But we can also learn a lot about cognitive and
neural infrastructure of some function by looking at individuals who are
'experts' in that function. Polyglots are one kind of language 'experts.'"
^ This is very interesting. ^
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