Researchers have discovered that speakers of four highly contrasting languages — Spanish, English, Hebrew and Chinese — show very similar patterns of brain activity during reading and speech, which suggests the underlying network for language processing might be more universal than previously understood.
At a news conference yesterday, where results of three international and interdisciplinary studies were announced, National Taiwan Normal University (NTNU) psychology professor Li Jun-ren (李俊仁) said his team tracked and compared reading and speech perception of native speakers of the four languages using functional magnetic resonance imaging and found mostly identical brain activation.
“We could not tell what language a participant speaks from their brain scan, because the same brain areas are activated regardless of what language they speak. We showed, for the first time, that there could be an invariant and universal brain network for reading and speech processing regardless of linguistic differences,” Li said.
It has been a topic of debate whether brain systems could be language specific, but the research showed that both the left and right hemispheres of the brain, but particularly the left hemisphere, are activated when speakers of any of the tested languages are performing reading or speech tasks, which suggests that language processing is predominantly operated by the left hemisphere, and that there could be a universal brain system for all languages, he said.
The finding debunks a myth that Chinese languages were predominantly processed by the right hemisphere, compared with alphabetic languages processed by the left hemisphere, because Chinese was considered a pictorial language and the right hemisphere has been associated with image processing, he added.
Other studies support Li’s findings: A study conducted by National Yang Ming University neuroscience professor Kuo Wen-jui (郭文瑞) discovered that two particular neural circuits, a shape recognition system and a gesture recognition system, are similarly activated and show identical patterns of activation in Chinese speakers and French speakers.
Meanwhile, similar activation patterns in two regions of the left inferior frontal lobe were found across Chinese and French participants when they are processing complex number words, such as seven-hundred-ninety-four, which suggests these regions serve as the neural bases for forming complex number words in different languages, according to a study by National Central University neuroscience professor Denise Wu (吳嫻).
“About 150 years ago, [French physician] Paul Broca proposed that the left hemisphere is responsible for language processing. Today, our team confirmed that reading, writing and arithmetic processing is done by the left hemisphere, which is a universal phenomenon across languages. The team’s findings are to be remembered for a long time,” former minister of education Ovid Tzeng (曾志朗) said.