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Bilingualism Comes Naturally to Our Brains

The brain uses a shared mechanism for combining words from a single language as well as ones from two different languages, a team of neuroscientists has discovered. The findings indicate that switching languages comes naturally to those who are bilingual because the brain has a mechanism that does not detect that the language has switched, allowing for a seamless transition in the comprehension of more than one language at once.

“Our brains are capable of engaging in multiple languages,” explains Sarah Phillips, an NYU linguistics doctoral candidate and the lead author of the paper, “Composition within and between Languages in the Bilingual Mind,” which appears in the journal eNeuro. “Languages may differ in what sounds they use and how they organize words to form sentences. However, all languages involve the process of combining words to express complex thoughts.”

“Bilinguals show a fascinating version of this process—their brains readily combine words from different languages, much like when combining words from the same language,” adds Liina Pylkkänen, the codirector of the Neuroscience of Language Lab at NYU Abu Dhabi, a professor in NYU’s linguistics and psychology departments, and the paper’s senior author.

A teacher instructs a student writing letters on a whiteboard

An estimated 60 million people in the United States use at least two languages, according to the US Census. Across the globe, the majority of people know more than one language. Indeed, many countries have more than one official national language.

Unsurprisingly, in today’s highly globalized world, bilingualism provides a variety of meaningful social and practical advantages. People using multiple languages can converse with a wider array of people, and they can also more readily connect across cultures and adjust to new situations. At NYU, students studying away benefit from exploring new places and having new experiences as members of the University’s global network. But they also have the opportunity to immerse themselves in a different language, deepening their experience and sharpening their minds.

Yet, despite the domestic and international widespread nature and evident benefits of bi- and multilingualism, the neurological mechanisms used to understand and produce more than one language are not well understood. This terrain is an intriguing one; bilinguals often mix their two languages together as they converse with one another, raising questions about how the brain functions in such exchanges.

Phillips and Pylkkänen sought to better understand these processes. They explored whether bilinguals interpret these mixed-language expressions using the same mechanisms as when comprehending single-language expressions or, alternatively, if understanding mixed-language expressions engages the brain in a unique way.

To test this, the scientists measured the neural activity of Korean and English bilinguals. The study’s subjects viewed a series of word combinations and pictures on a computer screen. Then, they indicated whether or not the picture matched the preceding words. The words either formed a two-word sentence or were simply a pair of verbs that did not combine into a meaningful phrase (such as, “icicles melt” versus “jump melt”). In some instances, the two words came from a single language (Korean or English) while others used both languages, with the latter mimicking mixed-language conversations.

In order to measure the study subjects’ brain activity during these experiments, the researchers deployed magnetoencephalography. The technique maps neural activity by recording magnetic fields generated by the electrical currents produced by our brains.

The recordings showed that Korean and English bilinguals, in interpreting mixed-language expressions, used the same neural mechanism as they did while interpreting single-language expressions. Specifically, the brain’s left anterior temporal lobe, a brain region well studied for its role in combining the meanings of multiple words, was insensitive to whether the words it received were from the same language or from different languages. This region, then, proceeded to assign complex meaning to two related words regardless of whether they shared a language.

These findings suggest that language switching is natural for bilinguals because the brain has a combinatory mechanism that does not “sense” the language has switched. “Earlier studies have examined how our brains can interpret an infinite number of expressions within a single language,” Phillips observes. “This research shows bilingual brains can, with striking ease, interpret complex expressions containing words from different languages.”

You can watch Phillips discussing her research on bilingual speakers in this NYU-produced video (credit: NYU, courtesy of Kate Lord).

Content repurposed with permission from NYU News

Professor Li Li Unpacks the Mysteries of the Brain

Professor Li Li’s career has taken her across the globe, from Lanzhou to Beijing and Rhode Island to Hong Kong. As a professor of neural science and psychology at NYU Shanghai, she’s worked in academia, at NASA, and in the private sector all while raising two daughters. Recently, she met with the NYU Shanghai News team to reflect on her journey across continents and industries—and share how she found her way back to academia in Shanghai.

You started your academic career as a Psychology major at Peking University (PKU). How did you settle on neuroscience as your field of study?

I followed a very typical growth path of a good Chinese student back in high school in Lanzhou, Gansu. I was good at taking exams and got a good grade on the gaokao [the national college entrance exams] to get into PKU. When deciding on my major, I picked Psychology because it seemed the most interesting and could provide me with opportunities to interact with people.

Psychology has many subareas, and I felt most interested in using experimental and computational methods to study rules and mechanisms underlying our cognition, which is also known as cognitive psychology. I still remember the shock I experienced when I entered the Perception, Action and Cognition Lab at Brown University for the first time about 20 years ago. Researchers in the lab were using these visual displays and virtual reality techniques to conduct scientific experiments and expand the boundaries of knowledge with so much passion. It made me say, “Wow, this is so cool!”

As a typical “science person,” the most attractive aspect of scientific research for me is that it allows data to speak for itself. I initially focused on memory and representation, but later on, I found that it was not strongly driven by data in many ways. So I shifted my focus to perception and action. I enjoy using scientific methodologies to study brains, and I am obsessed with the beauty of the logic, precision, and scientificity of research. I’m always searching for the keys to unaddressed questions through research.

You’ve worked in both academia and industry. How did you finally settle on university research and teaching as your life’s work?

After obtaining my PhD from Brown University and working as a postdoctoral researcher at Harvard Medical School, I gradually lost confidence in my career as an academic. I foresaw the entire career path, which lacked surprises and dampened my enthusiasm. I wanted to explore more possibilities, so I went into industry.

I worked as a human factors scientist at an engineering and scientific consulting firm in the Bay Area of California. But I soon became bored with the simple and repetitive procedural work I was assigned to do every day. More importantly, I felt I was wasting my graduate and postdoctoral training. Though the university salary was not as competitive as that in industry, I realized my true joy comes from figuring out the essence of the world and deciphering the mystery of the brain.

While making all these job shifts, I constantly asked myself what on earth I was working for. Did I work for intellectual challenges or monetary reward? The majority of people will choose to go into industry, leaving only a small group of people who can endure loneliness and stick to research. I eventually realized that the “lonely” research path fits me better.

Since joining NYU Shanghai, you’ve spent a lot of time and effort on building three different labs. Could you tell us more about them?

The first lab, the Perception and Action Virtual Reality Lab, focuses on using virtual reality techniques to study perception, control of self-motion, and eye–hand coordination. The second lab is the Perception and Action Neural Mechanism Lab, which focuses on examining the related underlying neural mechanisms. The third lab is the Neuropsychology Lab at Shanghai Ruijin Hospital. We study visuomotor and locomotion control in patients with neurodegenerative motor deficits, such as Parkinson’s disease.

Recently, we conducted a series of fMRI experiments and identified the areas of the brain where motion and form information are integrated for the perception of self-motion. We also examined baseball players’ basic visuomotor abilities and found that their basic eye-tracking ability could predict their potential to hit baseballs. Moreover, we discovered that visuomotor control ability becomes impaired and brain structure changes during the incubation period of neurodegenerative diseases.

As a teacher, what particular skills and traits do you encourage your students to cultivate to become more successful in the classroom or lab?

I’d like to share two things. First, the details are of paramount importance and play a decisive role in yielding extraordinary results in scientific experiments. As rigor and credibility lay the foundation for scientific research, I always ask students to pay more attention to the details, put more effort into the experimental design and the comprehension of logic, take the initiative to explore the reasons behind each step in the experiment, and prevent themselves from forgetfulness, carelessness, and taking anything for granted.

Second, long-term development in research should be supported by proficient academic writing skills. I urge my students to read more and practice their writing as much as possible so they can strengthen their sensitivity in using the English language and improve the logic and organization of their writing.

Lastly, what advice do you give to aspiring neuroscientists?

I think students who aim to study neuroscience should have intrinsic curiosity and thirst for knowledge about the nature of the brain. Thinking critically about the relationship between experiments and theory is also necessary. I suggest all students who want to make a career in science never give up or give in. In all areas of life, a successful person is not always the smartest person, but they are certainly the one who can stick it out until the end. As a perfectionist myself, I always hold an “excelsior” attitude toward work and research, and I hope that students will not be satisfied with their current situation. Only excellence can make endless progress.

This interview has been edited for clarity and length.

Content repurposed with permission from NYU Shanghai News and Publications