Bilingual brain: a preferred language for math?

The phenomenon of bilingualism is an important research topic in cognitive neuroscience. If you are bilingual you probably have felt the need to count or perform simple arithmetic – such as additions and multiplications-  using one particular language, even when communicating more frequently with your other language. You may wonder if your brain works differently compared to monolinguals or why you find more difficult to perform mental calculations when you are not using your preferred language for math. But for the brain, what it means to be bilingual?

Bilingual advantage yes or no?

Being bilingual has been linked to a number of cognitive benefits compared to monolinguals like excel at executive functions. Some of these highlighted executive function advantages are switching (flexibility in shifting between tasks), updating (sustained monitoring of working-memory contents), and inhibition (control of attention and ability to cancel a preponderant response). For decades, researchers have been debating the called “bilingual advantage” in these cognitive domains but the large majority of the published results – 83% of them – are inconclusive or contrary.

In the particular case of math performance, the open question refers to in which language bilinguals perform more efficiently arithmetic and what determines such math fluency in one language and not in the other. At the brain level, researchers are interested in knowing how this language specificity for math affects the brain organization and functioning.  And beyond arithmetic facts, how bilinguals activate non-symbolic numerical concepts like magnitude arouse especial interest in current research.

The role of language in math learning 

Unlike monolinguals, the bilinguals´ brain has to cope with two languages to map the same magnitude which poses differences in the organization of numerical system brain networks.  The main scientific assumption is that the language of early learning math determines the structure of numerical representations.  For bilinguals,  numerical concepts are manipulated more efficiently in the language in which they learned simple arithmetic. 

As language is necessary to retrieve arithmetic facts from memory, during early school years, the bilingual brain matches the numerical concepts with the language of teaching thus, forming an internal code. Using electrical brain recordings (EEG), researchers have investigated the numerical processing networks in bilinguals, showing very different functioning patterns. For example, a study from the University of  Texas assessed a group of Spanish-English bilinguals when judging the correctness of simple math problems presented in both languages.  Results showed that math problems presented as number words in English (five x four=twenty) or Spanish (cinco x cuatro= veinte) elicited different neural signatures as a function of the language of math learning compared to bilinguals´other language.

Furthermore, in my thesis dissertation, I investigated the neural patterns of bilinguals´ numerical representation as a function of the language of learning math. The results of my studies indicated that language plays an important role in how bilinguals´ brain responds to number words and represent the concept of magnitude. The brain signatures associated with numerical management in the language of learning math were consistent with a more automatic process compared to the neural response of bilinguals´other language. However, it is still unclear whether these brain signatures across languages are generated in the same or distinct areas of the bilingual brain.

One important question in today’s research is if the arithmetic memory networks established during childhood remain still in adulthood regardless of linguistic immersion. So far, there is only one study showing that bilinguals´ experience with arithmetics in the other language can diminish the advantage of the language of learning math.  However,  the study tested only a small sample of bilingual teachers and therefore, more evidence is needed to determine a possible change in bilinguals´ arithmetic memory networks. 

So…what can we conclude about bilingualism math case?

Excitingly, these research insights suggest that learning experience with one of the two languages shapes the bilinguals´ arithmetic brain networks. But this early experience also affects the representation of the concept of magnitude activating different brain mechanisms across both languages. Such representations tend to be maintained in adulthood independently of natural language dominance but arithmetic fluency in the language of learning math might be mitigated if a  continuous experience with the other language arises later in life.

Current research has the potential to lead our understanding of bilinguals neurodevelopment trajectories of arithmetic learning.  Knowing the role of language in mathematical acquisition in bilinguals will allow designing more efficient curriculums at schools and predict better math performance.