WASHINGTON, Jan. 29 (Xinhua) -- New evidences show that language is learned in brains systems that are also used for many other purposes, instead of innately-specified language modules as previously thought.
The study, published on Monday in Proceedings of the National Academy of Sciences, shows that children learn their native language and adults learn foreign languages in evolutionarily ancient brain circuits that also are used for tasks as diverse as remembering a shopping list and learning to drive.
"Our conclusion that language is learned in such ancient general-purpose systems," says the study's senior investigator, Michael T. Ullman, professor of neuroscience at Georgetown University School of Medicine.
"These brain systems are also found in animals -- for example, rats use them when they learn to navigate a maze," says co-author Phillip Hamrick of Kent State University.
The study has important implications not only for understanding the biology and evolution of language and how it is learned, but also for how language learning can be improved, both for people learning a foreign language and for those with language disorders such as autism, dyslexia, or aphasia.
The results showed that how good we are at remembering the words of a language correlates with how good we are at learning in "declarative memory," which we use to memorize shopping lists or to remember the bus driver's face or what we ate for dinner last night.
However, people's grammar abilities, which allow us to combine words into sentences according to the rules of a language, correlate strongly with learning in "procedural memory," which we use to learn tasks such as driving, riding a bicycle, or playing a musical instrument.
It shows that when adults learn a foreign language, grammar correlated with declarative memory at earlier stages, but with procedural memory at later stages.
"Researchers still know very little about the genetic and biological bases of language learning, and the new findings may lead to advances in these areas," says Ullman. "We know much more about the genetics and biology of the brain systems than about these same aspects of language learning."
"Since our results suggest that language learning depends on the brain systems, the genetics, biology, and learning mechanisms of these systems may very well also hold for language," Ullman says.
Ullman says, though researchers know little about which genes underlie language, numerous genes playing particular roles in the two brain systems have been identified. The findings from this new study suggest that these genes may also play similar roles in language.
Also, the findings may lead to approaches that could improve foreign language learning and language problems in disorders, Ullman says.
