A long-running debate in the linguistics community is centered around something called the Sapir-Whorf hypothesis, after Edward Sapir and his erstwhile student Benjamin Lee Whorf, two famous linguists who first formulated it most explicitly in the first half of the 20th century. Loosely put, the question is whether we experience the world around us through whichever language we happen to speak (as Sapir and Whorf believed), or if our mental “world views” are fundamentally language-independent.
In other words, does language shape our thoughts? Or do our thoughts – the product of some underlying cognitive processes common to all – shape our language?
As the battle raged on, Ellen Bialystok, Distinguished Research Professor of Psychology at York University, occupied herself by looking at something somewhat more tangible: what objective differences, if any, can be detected in the brains of those who speak two languages, as opposed to just one?
Somewhat surprisingly, perhaps, it turns out that there are a good deal more differences than we might, at first, have suspected. The first major distinction that Ellen appreciated concerned something called “metalinguistic awareness”.
“The most important linguistic achievement for young kids is developing what is called metalinguistic awareness: knowledge about language, understanding what language is and that it can be manipulated. If you don’t understand that language is a structured system, you can’t learn to read, because you can’t figure out that the things on the page refer to something in language. So metalinguistic awareness is crucial.
“In the first studies that started in the late 1970s and continued for about a decade, a number of people, including my own group, were looking at the development of metalinguistic awareness and finding that, by and large, bilingual children are ahead: they were developing these metalinguistic insights up to a year earlier.”
It seems that bilingual children, then, through their experience of regularly manipulating two languages from a very early age, develop a faster appreciation of the structure of language itself.
Well, that’s interesting, but perhaps not very surprising. And anyway, does it really matter? After all, just because bilinguals get there faster doesn’t necessarily mean all that much if we all get there eventually. But then Ellen started noticing other things.
It seems that, on average, bilinguals – both children and adults – performed decidedly better on standardized tests involving a large amount “cognitive interference”, when the subject was deliberately subjected to misleading information. These tests can be verbal (like the famous Stroop test, where subjects are asked to identify words like “green” based on the color of their ink, which is invariably in some other color) or non-verbal (measuring reaction times of dots on different sides of a screen with different hands).
It seemed, then, that the bilingual brain really is at least slightly different than its monolingual counterpart. Moreover, through a series of carefully designed experiments, Ellen and her colleagues demonstrated that the impact of such differences goes considerably beyond abstract psychological tests.
It was discovered that bilinguals, on average, performed objectively better at a series of diverse tasks – from driving while on a cell phone, to cooking many items at the same time – all of which involved an ability to successfully multitask, simultaneously filtering in and out different streams of information.
So clearly bilingualism had a real, measurable effect on our day-to-day lives, which naturally led Ellen to wonder if the impact of those differences might somehow accumulate – if a lifetime of being bilingual might somehow manifest itself in other ways. And that’s when things got even more interesting.
In a series of groundbreaking studies focusing on elderly subjects, Ellen and her group demonstrated that the first signs of dementia are typically delayed a whopping 4-5 years for bilinguals compared to monolinguals. Bilingualism is hardly a cure for dementia, it needs to be stressed, but somehow the bilingual brain is able to significantly delay the impact of severely debilitating diseases like Alzheimer’s.
Follow-up research using fMRI brain-scanning technology revealed that bilingual brains tend to have a slightly different neurophysiology – more grey matter and white matter – than their monolingual counterparts.
What is going on? Well, suffice it to say that multiple explanations abound. For her part, Ellen believes that the answer is linked to specific networks in the prefontal lobes that have been demonstrated to be linked to executive control.
“The theory, yet to be confirmed, is that because the front part of the brain, this important area where we find this set of executive processes, is more efficient for bilinguals, it’s better suited to provide compensation. The front part of the brain is kind of domain-general; it’s not used for just one thing.”
“In other words, having a robust front part of the brain can somehow carry you through as deterioration is happening elsewhere. It comes in as a kind of reserve.”
That sounds plausible enough. But how did these enhanced networks get developed in the first place? And how might the fairly prosaic act of speaking two languages change the very structure of our brains?
“What we now understand about the brain is that it is massively plastic. The brain is not a fixed framework of rigid connections, but is a dynamic, plastic system. It molds itself on the basis of what you’re asking it to do, and the more you train your brain, or require your brain to do certain kinds of things, the more it will reroute your neural circuitry to reflect those experiences, which means that the brain is a strong reflection of your experiences.
“If you think about it that way, it’s not so surprising that something as pervasive as the language, or languages, that you speak is going to rewire your brain. People are surprised that bilingualism rewires the brain. They think it’s crazy. But it isn’t crazy at all. Everything rewires the brain.”
Behold the plastic revolution.
Howard Burton, email@example.com
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