Learning a new language boosts brain activity, researchers find. This goes back down to baseline levels as skill improves, allowing us to track the process while it takes place inside the brain.
Our brains are highly tuned to understanding and using language. Not surprisingly, talking with others is a large part of the human experience. When we're learning a new language, different areas of the brain rev up and collaborate to understand what we're reading, hearing, and trying to say. A new study finds this process can be tracked as it is taking place in the brain, allowing us to measure our progress -- for the first bit, at least.
Big brain time
"In the first few months, you can quantitatively measure language-skill improvement by tracking brain activations," said Professor Kuniyoshi L. Sakai, a neuroscientist at the University of Tokyo and first author of the paper.
The study worked with 15 participants in their 20s from Europe who had studied English, but had no prior experience with Japanese and had not been to Japan. They moved to Tokyo, and the researchers tracked their progress during introductory Japanese classes (lasting at least three hours each day) taken there.
After at least eight weeks of testing, and six to fourteen weeks later, the participants took multiple-choice reading and listening tests. The authors explain these "passive" skills were favored over "active" ones like writing or speaking as they can be scored more objectively. A magnetic resonance imaging (MRI) scanner was used to record participants' brain activity during each test. MRIs can track blood flow inside the brain, which is a reliable indicator of neuronal activity.
Four regions of the brain -- the grammar center and comprehension area in the left frontal lobe, and the auditory processing and vocabulary areas in the temporo-parietal lobe -- are earmarked for language. Areas involved in memory and those handling sight also become active in support of these four. "Even in a native, second, or third language, the same regions are responsible," Sakai explains.
Significant increases in blood flow were seen for all participants during the first round of tests, suggesting they were still working hard to recognize characters or sounds. Overall, they scored about 45% accuracy on the reading tests and 75% accuracy on the listening tests. Randomly guessing would produce 25% accuracy, the team explains.
During the second test, average reading scores improved to around 55%. Accuracy on the listening tests didn't change, but the authors note that participants were faster to answer, suggesting they had a better grasp on what they were hearing. A slight increase in activation of the auditory processing area seen during the test suggests a clearer "mind's voice" while hearing, they add.
However, the authors also saw a decrease in brain activation: in the grammar center and comprehension area during listening tests, and the visual areas during the reading tests.
"Beginners have not mastered the sound patterns of the new language, so cannot hold in memory and imagine them well. They are still expending a lot of energy to recognize the speech in contrast to letters or grammar rules," said Sakai. "We expect that brain activation goes down after successfully learning a language because it doesn't require so much energy to understand".
"In the future, we can measure brain activations to objectively compare different methods to learn a language and select a more effective technique," he adds.
One potential application for these findings would be as a biometric tool to assess progress with language skills. But there are also medical applications, the authors explain, such as helping people regain language skills after brain injury or stroke.
The paper "Modality-Dependent Brain Activation Changes Induced by Acquiring a Second Language Abroad" has been published in the journal Frontiers in Behavioral Neuroscience.