The bilingual brain: Why one size doesn’t fit all
There is more than one type of bilingualism.
Over the past few years, you might have noticed a surfeit of articles covering current research on bilingualism. Some of them suggest that it sharpens the mind, while others are clearly intended to provoke more doubt than confidence, such as Maria Konnikova’s ‘Is Bilingualism Really an Advantage?’ (2015) in The New Yorker. The pendulum swing of the news cycle reflects a real debate in the cognitive science literature, wherein some groups have observed effects of bilingualism on non-linguistic skills, abilities and function, and others have been unable to replicate these findings.
Despite all the fuss that has been made about the ‘bilingual advantage’, most researchers have moved on from the simplistic ‘is there an advantage or not’ debate. Rather than asking whether bilingualism per se confers a cognitive advantage, researchers are now taking a more nuanced approach by exploring the various aspects of bilingualism to better understand their individual effects.
To give an idea of the nuances I am talking about, consider this: there is more than one type of bilingualism. A ‘simultaneous bilingual’ learns two languages from birth; an ‘early sequential bilingual’ might speak one language at home but learn to speak the community language at school; and a ‘late sequential bilingual’ might grow up with one language and then move to a country that speaks another. The differences between these three types are not trivial – they often lead to different levels of proficiency and fluency in multiple aspects of language, from pronunciation to reading comprehension.
In a recent study, Patricia Kuhl of the University of Washington and colleagues studied the effects of two ways in which a second language is used: listening and speaking. They used a technique called diffusion tensor imaging (DTI), which tracks flow of water through the brain, to measure white matter differences between Spanish-English bilinguals and English monolinguals currently living in the United States. The researchers used that data, in combination with bilinguals’ self-reported measurements of listening and speaking their second language, to analyse the effect of each of these experiences on the brain’s white matter.
Why white matter? Studying white matter – which is primarily composed of axons, the long, slender projectiles shunting signals across a nerve cell – is a way to measure connectivity between brain regions. If we think of the human brain as water in a cup (the cup being our skull), then white matter is like a straw in that cup: it constricts water flow in the direction that the axons are travelling. One common DTI measure, fractional anisotropy (FA), maps the overall shape of water flow in the brain. Another more specific measure, radial diffusivity (RD), helps researchers to pinpoint weak spots in the side of the straw, places where water might ‘leak’ out. In the healthy brain, researchers have long held, white matter will show high FA (flow in a single direction) and low RD (leaking of water in other directions).
Yet Kuhl and colleagues found that the monolinguals in their study had higher FA and lower RD in multiple white-matter tracts than the bilinguals – a seeming disadvantage for bilinguals. But the picture was not that simple. When they examined the effect of actual bilingual experience, or the estimated amount of time spent listening to and speaking the second language, they found that more bilingual experience lessened the differences between the bilinguals and monolinguals.
Specifically, more time spent listening to the second language was associated with lower RD in regions associated with language production (the anterior portion of the inferior fronto-occipital fasciculus). More time spent speaking the second language was associated with higher FA in regions of the brain associated with language comprehension.
In fact, when the researchers did a follow-up analysis comparing more and less experienced bilinguals to monolinguals, they found that bilinguals with at least four years immersion in the US had similar white-matter levels compared with the monolinguals. It was only the bilinguals with two years or less immersion in the US who showed significantly differing patterns from the monolinguals.
The results of this study should remind us that bilingualism is only one of many factors that can affect the brain. In this study, the unmentioned factor is that nearly all the bilinguals were immigrants, whereas none of the monolinguals were. There might be a whole range of factors that differ between countries to affect baseline white-matter levels, such as early nutrition and stress. Consequently, the comparison the authors made between immigrant bilinguals and non-immigrant monolinguals is not ideal, and we must interpret the overall difference between monolinguals and bilinguals in this study with caution. I believe the critical contribution here is not the overall difference between monolinguals and bilinguals, but the effect of bilingual experience: one where active use of your second language leads to healthier white matter.
The study reminds us how important it is to consider the experience of being bilingual; it is not terribly constructive to lump all bilingual studies together and make generalised evaluations. If you do want to lump them together, it’s worth remembering that regardless of proclaimed cognitive or anatomical advantages, bilinguals have twice as many communities to interact with, cultures to experience, and newspapers to read. And if that isn’t an advantage, what is? Millions of people study English as a second language every year for precisely these reasons (in fact, there are approximately three times as many non-native as native English speakers).
Even as a native English speaker, if I had never studied Spanish, I would likely not be writing this piece right now: my experiences as a language learner led directly to my interests in language and cognitive science. So let’s rewrite the story in the media. Bilingualism is an advantage. How it affects the brain, well, that’s a question we are still working on.
This article was originally published at Aeon and has been republished under Creative Commons.
It's just the current cycle that involves opiates, but methamphetamine, cocaine, and others have caused the trajectory of overdoses to head the same direction
- It appears that overdoses are increasing exponentially, no matter the drug itself
- If the study bears out, it means that even reducing opiates will not slow the trajectory.
- The causes of these trends remain obscure, but near the end of the write-up about the study, a hint might be apparent
Scientists think constructing a miles-long wall along an ice shelf in Antarctica could help protect the world's largest glacier from melting.
- Rising ocean levels are a serious threat to coastal regions around the globe.
- Scientists have proposed large-scale geoengineering projects that would prevent ice shelves from melting.
- The most successful solution proposed would be a miles-long, incredibly tall underwater wall at the edge of the ice shelves.
The world's oceans will rise significantly over the next century if the massive ice shelves connected to Antarctica begin to fail as a result of global warming.
To prevent or hold off such a catastrophe, a team of scientists recently proposed a radical plan: build underwater walls that would either support the ice or protect it from warm waters.
In a paper published in The Cryosphere, Michael Wolovick and John Moore from Princeton and the Beijing Normal University, respectively, outlined several "targeted geoengineering" solutions that could help prevent the melting of western Antarctica's Florida-sized Thwaites Glacier, whose melting waters are projected to be the largest source of sea-level rise in the foreseeable future.
An "unthinkable" engineering project
"If [glacial geoengineering] works there then we would expect it to work on less challenging glaciers as well," the authors wrote in the study.
One approach involves using sand or gravel to build artificial mounds on the seafloor that would help support the glacier and hopefully allow it to regrow. In another strategy, an underwater wall would be built to prevent warm waters from eating away at the glacier's base.
The most effective design, according to the team's computer simulations, would be a miles-long and very tall wall, or "artificial sill," that serves as a "continuous barrier" across the length of the glacier, providing it both physical support and protection from warm waters. Although the study authors suggested this option is currently beyond any engineering feat humans have attempted, it was shown to be the most effective solution in preventing the glacier from collapsing.
Source: Wolovick et al.
An example of the proposed geoengineering project. By blocking off the warm water that would otherwise eat away at the glacier's base, further sea level rise might be preventable.
But other, more feasible options could also be effective. For example, building a smaller wall that blocks about 50% of warm water from reaching the glacier would have about a 70% chance of preventing a runaway collapse, while constructing a series of isolated, 1,000-foot-tall columns on the seafloor as supports had about a 30% chance of success.
Still, the authors note that the frigid waters of the Antarctica present unprecedently challenging conditions for such an ambitious geoengineering project. They were also sure to caution that their encouraging results shouldn't be seen as reasons to neglect other measures that would cut global emissions or otherwise combat climate change.
"There are dishonest elements of society that will try to use our research to argue against the necessity of emissions' reductions. Our research does not in any way support that interpretation," they wrote.
"The more carbon we emit, the less likely it becomes that the ice sheets will survive in the long term at anything close to their present volume."
A 2015 report from the National Academies of Sciences, Engineering, and Medicine illustrates the potentially devastating effects of ice-shelf melting in western Antarctica.
"As the oceans and atmosphere warm, melting of ice shelves in key areas around the edges of the Antarctic ice sheet could trigger a runaway collapse process known as Marine Ice Sheet Instability. If this were to occur, the collapse of the West Antarctic Ice Sheet (WAIS) could potentially contribute 2 to 4 meters (6.5 to 13 feet) of global sea level rise within just a few centuries."
The world's getting hotter, and it's getting more volatile. We need to start thinking about how climate change encourages conflict.
- Climate change is usually discussed in terms of how it impacts the weather, but this fails to emphasize how climate change is a "threat multiplier."
- As a threat multiplier, climate change makes already dangerous social and political situations even worse.
- Not only do we have to work to minimize the impact of climate change on our environment, but we also have to deal with how it affects human issues today.
Human beings are great at responding to imminent and visible threats. Climate change, while dire, is almost entirely the opposite: it's slow, it's pervasive, it's vague, and it's invisible. Researchers and policymakers have been trying to package climate change in a way that conveys its severity. Usually, they do so by talking about its immediate effects: rising temperature, rising sea levels, and increasingly dangerous weather.
These things are bad, make no mistake about it. But the thing that makes climate change truly dire isn't that Cape Cod will be underwater next century, that polar bears will go extinct, or that we'll have to invent new categories for future hurricanes. It's the thousands of ancillary effects — the indirect pressure that climate change puts on every person on the planet.
How a drought in the Middle East contributed to extremism in Europe
(DANIEL LEAL-OLIVAS/AFP/Getty Images)
Nigel Farage in front of a billboard that leverages the immigration crisis to support Brexit.
Because climate change is too big for the mind to grasp, we'll have to use a case study to talk about this. The Syrian civil war is a horrific tangle of senseless violence, but there are some primary causes we can point to. There is the longstanding conflicts between different religious sects in that country. Additionally, the Arab Spring swept Syria up in a wave of resistance against authoritarian leaders in the Middle East — unfortunately, Syrian protests were brutally squashed by Bashar Al-Assad. These, and many other factors, contributed to the start of the Syrian civil war.
One of these other factors was drought. In fact, the drought in that region — it started in 2006 — has been described as the "worst long-term drought and most severe set of crop failures since agricultural civilization began in the Fertile Crescent many millennia ago." Because of this drought, many rural Syrians could no longer support themselves. Between 2006 and 2009, an estimated 1.5 million Syrians — many of them agricultural workers and farmers — moved into the country's major cities. With this sudden mixing of different social groups in a country where classes and religious sects were already at odds with one another, tensions rose, and the increased economic instability encouraged chaos. Again, the drought didn't cause the civil war — but it sure as hell helped it along.
The ensuing flood of refugees to Europe is already a well-known story. The immigration crisis was used as a talking point in the Brexit movement to encourage Britain to leave the EU. Authoritarian or extreme-right governments and political parties have sprung up in France, Italy, Greece, Hungary, Slovenia, and other European countries, all of which have capitalized on fears of the immigration crisis.
Why climate change is a "threat multiplier"
This is why both NATO and the Pentagon have labeled climate change as a "threat multiplier." On its own, climate change doesn't cause these issues — rather, it exacerbates underlying problems in societies around the world. Think of having a heated discussion inside a slowly heating-up car.
Climate change is often discussed in terms of its domino effect: for example, higher temperatures around the world melt the icecaps, releasing methane stored in the polar ice that contributes to the rise in temperature, which both reduces available land for agriculture due to drought and makes parts of the ocean uninhabitable for different animal species, wreaking havoc on the food chain, and ultimately making food more scarce.
Maybe we should start to consider climate change's domino effect in more human and political terms. That is, in terms of the dominoes of sociopolitical events spurred on by climate change and the missing resources it gobbles up.
What the future may hold
(NASA via Getty Images)
Increasingly severe weather events will make it more difficult for nations to avoid conflict.
Part of why this is difficult to see is because climate change does not affect all countries proportionally — at least, not in a direct sense. Germanwatch, a German NGO, releases a climate change index every year to analyze exactly how badly different countries have been affected by climate change. The top five most at-risk countries are Haiti, Zimbabwe, Fiji, Sri Lanka, and Vietnam. Notice that many of these places are islands, which are at the greatest risk for major storms and rising sea levels. Some island nations are even expected to literally disappear — the leaders of these nations are actively making plans to move their citizens to other countries.
But Germanwatch's climate change index is based on weather events. It does not account for the political and social instability that will likely result. The U.S. and many parts of Europe are relatively low on the index, but that is precisely why these countries will most likely need to deal with the human cost of climate change. Refugees won't go from the frying pan into the fire: they'll go to the closest, safest place available.
Many people's instinctive response to floods of immigrants is to simply make borders more restrictive. This makes sense — a nation's first duty is to its own citizens, after all. Unfortunately, people who support stronger immigration policies tend to have right-wing authoritarian tendencies. This isn't always the case, of course, but anecdotally, we can look at the governments in Europe that have stricter immigration policies. Hungary, for example, has extremely strict policies against Muslim immigrants. It's also rapidly turning into a dictatorship. The country has cracked down on media organizations and NGOs, eroded its judicial system's independence, illegalized homelessness, and banned gender studies courses.
Climate change and its sociopolitical effects, such as refugee migration, aren't some poorer country's problem. It's everyone's problem. Whether it's our food, our homes, or our rights, climate change will exact a toll on every nation on Earth. Stopping climate change, or at least reducing its impact, is vitally important. Equally important is contending with the multifaceted threats its going to throw our way.
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