Memory Module Explains Super Language Learners (fwd)

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Memory Module Explains Super Language Learners
More active in people with greater proficiency in foreign tongues

By Gabe Romain
Betterhumans Staff
10/4/2004 4:12 PM
http://www.betterhumans.com/News/news.aspx?articleID=2004-10-04-2

The ease at which some people adopt a second language may stem from a
highly proficient short-term memory module.

Researcher Michael Chee and colleagues at Singapore General Hospital
have found that the activity of brain regions controlling phonological
working memory (PWM)—the type of short-term memory used to remember
letters, words and digits—is greater in people who are highly adept at
learning a new language.

"The key finding in the present study relates to people who have
excellent first-language attainment and who despite having comparable
impetus to be bilingual differ in second-language proficiency," say the
researchers. "We found that these individuals show differences in
cortical activation that suggest an important contribution of PWM to
language attainment."

Sound memory

Research has shown that PWM is crucial for learning a new language.
Specifically, it has been proposed that something called the
phonological loop exists to facilitate language acquisition.

The phonological loop consists of the phonological store and the
articulatory control process. The phonological store can retain
speech-based information for a short period—unless rehearsed, the
memories fade within seconds. The articulatory control process involves
subvocal rehearsal aimed at offsetting the decay of recently acquired
memories.

A number of behavioral studies have shown that measures of PWM predict
the outcome of native language acquisition in children and foreign
language acquisition in both children and adults, say the researchers.

Moreover, studies on people with short-term memory deficits, language
impairment and low scholastic achievement have revealed that PWM
appears to be crucial for language acquisition.

Brain differences

To determine what PWM-related brain regions contribute to language
learning, Chee and colleagues investigated the correlation between PWM
in people termed "equal bilinguals" and people labeled "unequal
bilinguals."

English was the first language of both groups, however, equal bilinguals
were also highly proficient in Chinese, whereas unequal bilinguals were
less adept in Chinese.

To evaluate the brain regions involved in PWM, participants were scanned
with magnetic resonance imaging while performing an auditory test.
Successful performance of the test required continuous updating and
temporal reordering of phonological information.

Equal and unequal bilinguals performed the task equally well. Equal
bilinguals, however, showed greater activation in cortical areas that
participate in PWM, whereas unequal bilinguals showed greater
activation in brain areas that are engaged in goal directed processing.

"Taken together, these observations support the overall construct that
unequal bilinguals show differences in neural activation patterns that
may belie a less efficient processing strategy that correlates with
poorer second-language attainment," say the researchers. "The extent to
which such processing differences are the cause or consequence of
impaired second-language attainment remains to be explored."

The research is reported in the Proceeding of the National Academy of
Sciences (read abstract).