Multilingualism: Does Knowing Multiple Languages Improve Working Memory?
Walking down the streets of Philadelphia, you see a large commotion by a nearby store. It just so happens that one of your brother’s best friends — let’s call him Kwaku — is involved in the fight. You squint your eyes and see the name of the store written in Chinese, running across the storefront. You’ve never seen this store before, but you want to tell your brother where this is happening so he can help — so you sprint home, desperately trying to hold the store name in mind while navigating through the busy streets of the city. Believe it or not, the fact that you can read the store name in Chinese may be aiding your swift return home.
To accomplish this task (yes, I know it’s a task quite fantasized, but please bear with me), you employ what cognitive scientists call your working memory, arguably one of the most important components of cognitive processing[1]. Working memory is one of the core functions of your brain’s executive system and has broadly been defined as the brain’s capacity to provide temporary storage and manipulation of information to complete complex cognitive tasks (Baddeley, 1992). In the desperate attempt to reach your brother, your brain is busy compartmentalizing the information associated with the store commotion and the information associated with how to get home safely and quickly — along with emotional and bodily exertion. While on the surface you do this seamlessly and unconsciously, I can assure you this is no trivial task for your brain. Thousands upon thousands of densely connected neurons are being fired at extremely fast speeds in your brain to accomplish this. This can be hard to imagine, so check out this video for a 3D animation of neurons firing!
Pretty crazy how the brain works, right?
Now, I’m sure you can think of many examples of needing to employ the working memory in day-to-day tasks, whether it be trying to cook lunch as you watch your favorite TV show, or singing along to a familiar tune as you fold your laundry. What’s more — and you may find this surprising — people can engage their working memories as they speak! How is this possible?
Let’s go back to our opening example, where I assumed that, in addition to your native language of English, you can speak and read Chinese. This simple act of reading and interpreting the store name is recruiting the executive functions of the brain — precisely because the you from earlier knows two languages. This ability to understand and speak more than one language is known as multilingualism (Diamond, 2010). Multilingualism is a growing area of research in cognitive science, with researchers seeking to understand how its production and learning differs from monolingualism (the ability to speak and understand only one language). Various studies have demonstrated that speaking two or more languages daily produces changes in cognitive performance (Bialystok, 2009). For example, as I alluded to earlier, what if I told you that your ability to read in Chinese helped you navigate the second working memory task better — the task of going home quickly while remembering the store commotion? In the rest of this blog, I will dive deeper into the question of whether multilingualism affects one’s working memory, consider possible conclusions/theories, and address any further questions that remain. Let’s go!
Working memory differences in monolingual and multilingual children
Studies have demonstrated the potential advantages that being multilingual might confer (Kroll et al., 2015; Antón et al., 2014; Bialystok & Barac, 2012). To convince you, let us first look more closely at a study by Morales et al. 2013 comparing working memory development in monolingual and multilingual children. To preface, studying working memory in children is especially important since it is involved in essential cognitive abilities like reading comprehension and mental arithmetic (Kane et al., 2007). As such, working memory and, more broadly, the brain’s executive function may serve as a potential predictor for academic outcomes in children (Espy et al., 2004; Gahercole et al., 2004).
In their study, the researchers had 5- to 7-year-old children perform various picture working memory tasks. Briefly, the children were shown a 500-ms blank screen. This was followed by a centered fixation cross for another 500-ms, which directs the subject’s gaze toward the middle of the screen. In the non-conflict condition (you can think of this as a control group), they were then presented with one of two images, a heart or a flower, for a maximum of 3000-ms. Following this stimulus, the children were instructed to press the key to their right if they saw a heart and the key to their left if they saw a flower.
To assess working memory, the researchers created a conflict condition. In this more complex condition, the children were presented with the same images, but the images were no longer positioned in the center of the screen but on either the right or left side of the screen. The idea was that sometimes, the position of the image on the screen would be on the same side as the position of the key (congruent trials), but for other trials, they would be on opposite sides (incongruent trials). The reason this recruited a child’s working memory is that he or she would have to inhibit using the position of the image to accurately classify it as a heart or flower, thereby testing the child’s ability to discriminate among inputs. (My head hurts just thinking about doing this task — imagine how hard the child’s neurons are working at this point…)
A common theory was that working memory performance would be better in bilingual children because the joint processing of multiple languages requires inhibition of one language while maintaining the representation of the other — both of which are functions of working memory (Green, 1998). In other words, since bilingual children may recruit their working memory more frequently to accomplish daily linguistic tasks, their use of the working memory may be more proficient in accomplishing other cognitive tasks.
Imagine an experienced cellist who has mastered the instrument. He would more likely learn other musical instruments quicker than a beginner cellist with little to no experience because of his existing, simultaneous knowledge of music theory (the “language” of music, if you will). I mean, if you don’t believe me, take a look at this video — this experienced cellist couldn’t find a violinist to play with, so he decided to pick it up himself. And he sounds wonderful on both (feel free to try using your working memory by listening to the music as you read the rest of the blog)!
While this is a rough analogy, my point stands — bilingualism seems to equip children with a certain affinity with their working memory, which is a function of the brain not just employed in a linguistic context.
Morales’s results confirmed this theory. First, in the non-conflict condition, both monolingual and multilingual children showed a high level of accuracy since executive function demands were low. However, the conflict condition produced significantly different results for the two language groups. Whereas incongruent trials were more difficult than congruent trials for monolinguals, the misleading cues did not affect bilinguals significantly. This demonstrated that bilingual children may have an advantage in conflict resolution, particularly in a cognitive context.
Now, how about working memory in adults?
Okay, so far I’ve been talking about multilingualism’s effect on working memory in children — and for good reasons. As I’ve said before, studying executive functions is especially important for understanding the early stages of development. But at this point, I’m sure you’re asking the question — what about adults? To answer this question, let’s briefly take a look at a recent study by Cockcroft et al. 2019 comparing working memory ability in multilingual and monolingual young adults.
In their study, the researchers used the Automated Working Memory Assessment (AWMA)— which is, in simple terms, a computer program assessing working memory (Baddeley, 2000). The AWMA consists of various tests for working memory components. For example, one of the tasks assessing visuospatial processing is the Mazes Memory task. Here, participants viewed a maze with a red pathway, and after a brief delay, had to re-trace the path on a blank maze. A few of the tasks were complex tasks involving executive processing (remember the incongruent trials in the heart and flower experiment from before?) and simpler tasks involving less strenuous memory storage (analogous to the congruent trials from before).
As you might have guessed, the conclusions drawn were similar to the previous studies assessing working memory in children. There was evidence of a multilingual advantage in working memory tasks, especially those that involved visuospatial processing. As with children, multilingual adults developed an advantage in the executive control aspect of the brain. It is also worth noting that this multilingual advantage, according to Cockcroft et al., need not be specific to working memory but may reflect more generally a stronger control for executive processing.
Working memory for cognitive science more broadly…
Phew, that was a lot — so what’s my bigger point? Why would the you from earlier, running along the streets of Philadelphia, care about all of this? Yes, working memory performance differs between multilingual and monolingual individuals, and I’ve walked through studies that demonstrate this. But as I already hinted at, working memory also has implications in understanding the cognitive development of multilingual individuals more generally. If you, the reader, happen to be multilingual, briefly consider how you were able to learn a second, third, or however many languages you speak. Then consider what kind of decisions, expressions, or habits that you’ve developed because of the various cultural practices and norms resulting from these languages. For example, maybe as a Chinese speaker, your language has made more salient the richness of linguistic vocabulary, or for the beauty that comes in art and painting (for all those calligraphy fanatics, I’m sure you can relate).
While these results may not explicitly account for all developmental differences, studies show that executive function differences (AKA working memory differences) certainly influence — whether directly or indirectly — other aspects of the typical developmental trajectory (Cowan, 2014). And for all those linguistic fanatics, Cowan and I are not necessarily arguing for a Whorfian effect here, or a linguistic relativity that suggests language is the driver of one’s worldview. Rather, I am claiming that working memory is a foundational cognitive function that is very much working alongside other important functions. In cognitive science, it’s important to not only address each region of the brain as separate micro-entities but also to consider how they are mutually interconnected. Therefore, understanding the influence that multilingualism has on one’s working memory is also important in understanding cognition more broadly. Pretty cool, right?
Concluding remarks and future questions
Before I end, I want to make a quick disclaimer — I am not saying multilingual individuals automatically have an inherent advantage in neural functionality and are “better” than monolingual individuals. In fact, studies show that monolingual individuals perform just as well as multilingual individuals in various cognitive tasks (eg. Werker, 1986). Furthermore, studies have even reported certain disadvantages in multilingual individuals when performing verbal tasks (Bialystok et al., 2010; Cockcroft et al., 2019). Thus, the purpose of this article is to simply highlight a specific area in cognition that is affected by multilingualism — not to broaden this working memory “advantage” to all aspects of cognition.
With this being said, multilingualism is an area of study that still needs further study. There is still a lot that cognitive scientists don’t know about multilingualism —for example, what are the precise neural mechanisms in which multiple languages (and subsequent working memory differences) are developed and learned? What are the social/cultural/political implications of countries where multilingualism dominates? Researchers also aren’t completely sure whether executive function differences can be directly applied to a multilingual framework, since there are potential confounding factors that can influence cognitive development over one’s lifetime (Cenoz & Genesee, 1998).
Despite how much we have yet to uncover, I still believe that the current research shows that multilingualism has the potential to positively impact society. I mean, if it weren’t for multilingualism, your brother may have not been able to help Kwaku in time…
But in all seriousness, studies show that multilingual practices may have many benefits, including benefits toward education, enhanced communication skills, enhanced creativity, and increased cultural awareness (Okal, 2014). As if this wasn’t enough, I hope I’ve convinced you today that multilingualism may have benefits toward one’s working memory, which has applications to decision-making, cognitive processing, and other non-linguistic daily behaviors.
If you have the time and desire, I encourage you to try and pick up another language or two — I promise it’s worth it :)
[1] For more fun, engaging content on working memory, check out this TED talk by Peter Doolittle!
References
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