Study Of Language Use In Children Suggests
Gender Influences How Brain Processes Words
November 30, 2006
Boys and girls tend to use different parts of their brains to process some basic
aspects of grammar, according to the first study of its kind, suggesting that
sex is an important factor in the acquisition and use of language.
Two neuroscientists from Georgetown University Medical Center discovered that
boys and girls use different brain systems when they make mistakes like
"Yesterday I holded the bunny". Girls mainly use a system that is for
memorizing words and associations between them, whereas boys rely primarily on a
system that governs the rules of language.
"Sex has been virtually ignored in studies of the learning, representation,
processing and neural bases of language. This study shows that differences
between males and females may be an important factor in these cognitive
processes," said the lead author, Michael Ullman, PhD, professor of
neuroscience, psychology, neurology and linguistics.
He added that since the brain systems tested in this study are responsible for
more than just language use, the study supports the notion that "men and
women may tend to process various skills differently from one another." One
potential underlying reason, suggested by other research, is that the hormone
estrogen, found primarily in females, affects brain processing, Ullman said.
The study, whose co-author is Joshua Hartshorne, was published earlier this year
in the journal Developmental Science.
Researchers know that women tend to be better than men at verbal memory tasks,
such as remembering word lists, and that this ability depends on declarative
memory. Included within declarative memory is a "mental lexicon" in
which word forms are memorized and remembered. The grammatical rules that allow
us to combine words in sentences depend on "procedural" memory.
Researchers have found that both boys and girls may be equally adept at this
process, which depends on a different part of the brain than declarative memory.
In this study, Ullman and Hartshorne hypothesized that girls would be better
than boys at remembering irregular past-tenses of verbs, like "held",
since these words are memorized in declarative memory. And if girls remember
"held" better than boys, they should make fewer errors like "holded",
since these "over-regularization" errors are made when children can't
remember irregular past-tenses, and so resort to combing the verb with an -ed
ending, just as they do for regular verbs like "walked".
So they studied how a group of 10 boys and 15 girls, age 2 to 5, used regular
and irregular past-tense forms in their normal speech. To their surprise, and
contrary to their predictions, the researchers discovered that the girls
over-regularized far more than boys.
They then investigated which verbs the girls made the mistakes on, and found an
association between the number of similar sounding regular past-tense verbs, and
the particular verb that was over-regularized. For example, girls tended to say
"holded" or "blowed" because many other rhyming verbs use
the regular past-tense form (such as folded, molded, and flowed, rowed, stowed,
respectively).
The researchers say this kind analogy-based processing suggests the girls were
relying on their declarative memory to create the past tense. "This memory
is not just a rote list of words, but underlies common patterns between words,
and can be used to generalize these patterns," Ullman said. "In this
case, the girls had memorized the regular past tenses of rhyming words, and were
generalizing these patterns to new words, resulting in over-regularization
errors" such as "holded" and "blowed".
In contrast, for the boys there was no association between the number of similar
sounding regular past-tense verbs, and the particular verbs that were
over-regularized. So the boys did not make more over-regularizations on verbs
like "holded" or "blowed" that have many rhyming regular
past-tenses. This suggests, Ullman said, that the boys were not forming these
words in declarative memory, but were probably using the rule-governed system to
combine verbs with -ed endings.
Other types of evidence also suggest that adult women tend use declarative
memory more than adult men do in their use of language, Ullman said.
"Although the two sexes seem to be doing the same thing, and doing it
equally well, they are using two different neurocognitive brain processes to do
it,' Ullman said. "This is a novel and exciting finding."
About Georgetown University Medical Center
Georgetown University Medical Center is an internationally recognized academic
medical center with a three-part mission of research, teaching and patient care
(through our partnership with MedStar Health). Our mission is carried out with a
strong emphasis on public service and a dedication to the Catholic, Jesuit
principle of cura personalis -- or "care of the whole person." The
Medical Center includes the School of Medicine and the School of Nursing and
Health Studies, both nationally ranked, the world-renowned Lombardi
Comprehensive Cancer Center and the Biomedical Graduate Research Organization (BGRO).
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Contact: Becky Wexler
Georgetown University
Medical Center
http://www.medicalnewstoday.com
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