Bilingual children’s brains are more efficient and, later in life, show slower cognitive decline when experiencing ageing and dementia.
Immigrant parents often avoid speaking their native language at home for fear of confusing their children by presenting two languages at once. That’s a shame, because learning to be bilingual actually improves children’s concentration – and that enhanced focus offers lifelong advantages.
Bilingualism strengthens the attention system in the front of the brain, because constantly selecting from two available languages enhances powers of concentration. These powers are essential for many other important mental tasks.
The crucial factor is that when bilingual people speak, both their languages are activated. Yet they rarely make the mistake of choosing a word from the wrong language. That’s because the front of the brain – the prefrontal cortex – focuses their attention on whichever language is required at any particular moment. So an Anglo-French speaker talking to a monolingual British person won’t say “chien” instead of “dog”. The mental gymnastics of constantly focusing in this way – for hours every day – builds the attention system, providing vital strengths that can then be used in other cognitive tasks.
Filtering information, helping concentration
This training for the attention system provides a great advantage. All the information that bombards us is filtered first through the front of the brain. We have to sift through information to focus on what our sensory and cognitive systems should be considering at any particular moment. In other words, we have to selectively attend to the information that’s needed for the tasks we’re currently performing.
“The real advantage is more profound: bilingualism rewires the brain in ways that matter throughout life, even into old age and cognitive decline.”
A selective attention system is essential for everything we do. For example, when you drive down a highway, it helps you spot your exit sign without being distracted by billboards. When you’re typing, it helps you focus your attention on writing even if someone is shouting in the background. When children are studying multiplication and division, it helps them focus on the integers and on learning the various operations, rather than being distracted by something else going on in the classroom.
Building the capacity to concentrate is a key part of children’s development in the first five years of life. They need the ability to focus on important elements of a problem without being distracted by irrelevant and misleading information. Indeed, the progress that children achieve in their attention capacity during these early years is a predictor of long-term academic success. However, children’s progress around concentration can be slow.
In recent years, neuroscience has found that the neural pathways governing attention aren’t fully connected until later adolescence. As a result, many focusing tasks can be highly challenging for children. For example, if you say to 4-year olds, “Try to sit still, colour in and I’ll tell you when dinner is ready,” they often have trouble blocking out other distractions to do as requested.
So the importance for children of concentration – combined with their immature development – helps explain why strengthened attention systems are such an asset to bilingual speakers.
Other factors also help build the frontal attention system. Research shows that socioeconomic status, for example, is crucial for the attention system’s healthy and rapid development: young children from better-off families typically have more well-developed attention systems and perform better on tasks that require concentration and selective attention. However, bilingualism is separate from those effects; even in poorer families, bilingualism promotes development of the frontal attention system.
Being bilingual rewires the brain
Some of this advantage might be dismissed as simply accelerated progress – bilingual children excelling at a mental task which their monolingual peers will be able to achieve just as well in perhaps six months or a year. However, studies show that the real advantage is more profound: bilingualism rewires the brain in ways that matter throughout life—even, we’re beginning to understand, into old age and cognitive decline.
Research demonstrates that even when bilinguals perform a task with the same success as their monolingual peers, their brains are functioning in a different way. First, imaging shows that bilinguals’ brains require less activation to achieve the same level of performance than the brains of monolingual people. In other words, bilingual brains are more efficient, needing less fuel, which frees up capacity for other tasks.
Second, the normal cognitive decline that’s characteristic of most people as they age is slower in bilingual people. We don’t know why, but we do know, from imaging, that connections among regions of the brain are different for bilingual people. So it could be that when parts of the brain age, other parts step in more effectively for bilingual people and compensate when a problem is difficult. A particularly interesting research finding that supports this hypothesis concerns dementia. Although dementia occurs and progresses similarly for bilingual people as for their monolingual peers, among bilinguals the cognitive symptoms are typically delayed by four or five years.
“The importance for children of concentration – combined with their immature development – helps explain why strengthened attention systems are such an asset to bilingual speakers.”
The story of bilingualism is not all a story of advantage. Typically, bilingual speakers, especially children, have less command of either language than their monolingual peers have over a single language. On average, bilinguals have a smaller vocabulary and more difficulty retrieving words and forming sentence structures. It’s vital that educators understand these potential weaknesses, since norms for standardized test scores were created for monolingual, English-speaking children. These tests can therefore lead to mistaken diagnoses for bilingual children and should be recalibrated to accommodate this group.
Message to policy makers and educators
Policy makers and educators should understand that bilingualism is an asset and that they shouldn’t treat it like a disease to be prevented. We know, for example, that Hispanic children in the United States – who rank low on socioeconomic curves – achieve their best outcomes when Spanish is spoken in the classroom. Speech and language clinicians should understand a child’s entire language profile at home and at school. They should not be afraid to say: “We need to build up her Portuguese because that’s going to help her to learn English in the long run.”
Finally, setting aside the attention and cognitive advantages available to bilingual children, this language issue also concerns their social and emotional well-being, which is important to every aspect of their progress. Bilingualism is typically an enriching experience for reasons of culture and identity. Home languages connect children to their ancestors, their grandparents and their extended families. These connections should be valued and developed, not hampered by insensitive approaches to bilingualism.