Shining a Light on How Bilingual Children Learn

There's a cute little curly headed cherub in a yellow dress, and she is the star of the show. She's sitting on her mother's lap and her mother is talking to her in that gentle mother voice that says, despite all appearances, this is normal, you are safe and there will probably be a nice treat for you for cooperating. A scientist and her research assistant, neither of whom the child has met before, hover around her in a smallish room with a desk, some electronic equipment and a flat-screen TV.

Two-year-old Lena has already refused twice to wear the strange stretchy cap with a chin strap and bundle of wires tethered to a computer. A round of "Baby shark"—and a snack from mom—helped calm her a little. But she's still fidgety. The assistant tries a distraction: she waves a plastic wand with a ball on the end that blinks different colors. Maria Arredondo sneaks up and slips on the cap. Now they have to work fast.

"I tested 300 babies during my postdoctoral studies," Arredondo says. "And as you saw, the samples for that paper are quite small, less than a hundred, because it's not just about the brain activity, but it's also about compliance from the baby."

Arredondo, an assistant professor of human development and family sciences who runs the Child Learning and Development Studies Lab at The University of Texas at Austin, is trying to understand how growing up in a bilingual environment affects a child's learning. The focus of her research grew out of a very personal curiosity. She first learned English when she moved from Argentina to the U.S. at the age of 12.

"I found it very interesting how my parents and older sister struggled to learn a new language," she says. "But my younger brother had a really easy time. And so I wondered: why do some people struggle and some people seem to find it very easy?"

She's interested in how children learn multiple languages, but also in how the underlying skills needed to learn them bleeds over into other kinds of learning. There's a hotly debated hypothesis in this field that bilingual children are better at higher cognitive functions that are critical for learning—such as memory, inhibitory control and attention—compared to monolingual children. If true, perhaps bilingual children are better at learning all kinds of things. Experiments designed to test this idea have had mixed results.

Arredondo has three short tasks planned for Lena today designed to test some of the fundamental skills related to learning.

What's on Your Mind?

Lena lives in a household where only one language, English, is predominantly spoken. The cap on her head uses infrared light to safely map brain activity in real time. It's part of a technique called fNIRS, functional near infrared spectroscopy, that measures the level of oxygenation in different areas of the brain. Areas of the brain that are engaged, for example when listening to speech, use more oxygen.

After several years of training and hundreds of infants and children participating in her studies, Arredondo has learned how to put children at ease.

"Kids get scared easily," Arredondo says. "We try to have an environment where they feel free to move around and feel comfortable, and they can understand that this is a safe environment. This is a place to play and be themselves."

In the first task, the research assistant shows Lena a soft yellow duck puppet wearing a black hat. She performs a set of actions, including taking off the hat and putting it back, and taking a pair of mittens out of a pocket, shaking them and putting them back. The assistant puts away the duck and brings out a white lamb doll and the same accessories, then she gives Lena a go. Can she repeat the various actions that the assistant did with the first puppet? The goal is to see what parts of her brain are active when she is remembering what she learned before.

Combining brain activity patterns from monolingual learners like Lena and bilingual learners can help tease out differences in the ways they carry out higher cognitive functions like this memory task.

Another of the key skills needed to learn new things, including languages, is the ability to tune out distractions and block automatic but incorrect responses, also known as inhibitory control.

For the second task, Lena is shown a screen with two squares—one black and one with a smiley face. The smiley face is consistently on the same side of the screen each time it appears. She learns that if she presses on the smiley face, she gets a bonus—an apple appears and a fun little bit of music plays. Then the researchers switch which side the smiley face is on. And at first, she continues to touch the same side of the screen, but no longer gets the added bonus. Eventually she shifts to the other side.

"We're looking at inhibitory control, whether they can inhibit that original response and switch to the new location," Arredondo says.

In the third task, the assistant points to a picture of a ball. "Look at the ball!" Then she repeats this with another familiar object, a car. Next, she presents Lena with an object that she has never seen before—a made-up toy that looks like a rubbery mass of multicolored, teardrop shaped blobs. "Look at the dax!"

To learn this new word, she has to call on other skills like memory and attention. The researchers are interested in patterns of brain activity that accompany learning the name of the new object and how those differ between bilinguals and monolinguals.

"In bilinguals, we're doing the experiment in English and in Spanish," Arredondo says. "So we're interested in seeing whether the amount of exposure they're getting in each of those languages affects whether they map that word better in one language over the other."

Do Bilinguals Learn Better?

Bilingualism is pretty impressive when you stop to think about it. Bilingual learners spend less time hearing and speaking each of their languages, and yet to be successful in both, they have to learn twice as many words as a monolingual child.

There is at least some support for the idea that bilinguals are better than monolinguals at the higher cognitive skills that undergird learning. For example, other researchers have found that bilingual learners are better at some tasks involving attention, such as switching from seeing a duck to a rabbit in an ambiguous image. Perhaps that's because growing up in a bilingual household, they have to switch their attention between two languages quickly.

During her postdoctoral studies at the University of British Columbia, Arredondo used fNIRS to study 6- and 10-month-old infants from bilingual and monolingual households performing a task that tested what is known as orienting attention, the ability to engage with and switch between sensory inputs such as sounds or visual stimuli. In this case, a familiar object (such as a beach ball) appeared in different locations on a computer screen and the researchers recorded where the children gazed and how long it took them to shift attention from one place to another.

Arredondo found that babies from bilingual households had more brain activity in the left frontal region, which is associated with language processing and language production, during the task than babies from monolingual households. Interestingly, those bilingual babies who had the most increase in brain activity within this region were the ones who were exposed to higher levels of "code-switching"—toggling between multiple languages—at home and were also more likely to perform the task correctly. And the bilinguals showed more improvement from age 6 months to 10 months than monolinguals.

Taken altogether, Arredondo's findings suggest that code-switching between languages in the home might sharpen bilinguals' attention and boost learning.

"These papers show that bilinguals' brains and ability in attention are adapting to their environment and improving over time," Arredondo says. "It's possible this code-switching environment is making them better at learning, but we don't fully know that from this data. It's all correlational."

After about 15 minutes, Lena has had enough of the cap and is tugging at it. This wasn't a test of endurance, but if it were, she would have passed with flying colors. She played along with the researchers and sat through all three experiments wearing the cap.

"She was one of the best participants," Arredondo says. "Even though she took time to warm up, she did amazing."