About half of the population speaks two languages perfectly. In addition to the obvious advantages when travelling to other countries or looking for a job, bilingual people have better skills such as memory or attention. Recent research has also shown that their brains delay the symptoms of dementia and that they recover better after suffering a stroke.
In terms of our memory, mental calculations or understanding a text, we use what is called the working memory, which is related to the temporary storage of information and its processing. This ability develops during childhood.
According to research from the universities of York (Canada) and Granada (Spain), bilingual children between five and seven years old who participated in the study performed better than the monolingual ones on those tasks that involved using the working memory. In addition, this ability benefited the development of other executive functions, especially when these functions were interacting with each other.
Other studies have also analysed the development of these functions, but taking into account the family income level of the children participating.
Pascale Engel de Abreu, director of the Language and Cognitive Development group at the University of Luxembourg, participated in a study in which they compared the different cognitive abilities of 80 second-grade students, all from low-income families. Half of the children lived in Luxembourg and spoke both Luxembourgish and Portuguese, while the rest resided in Portugal and used only Portuguese.
As Engel de Abreu explains to OpenMind, bilingual students displayed cognitive advantages compared to monolinguals. These skills focused on executive functions, “especially tasks tapping into cognitive conflict resolution,” she adds.
Although those students who mastered two languages knew fewer words than their monolingual peers, they performed the control tasks better, i.e. those that required selective attention and the elimination of interference.
Along with better attention and memory, speaking two languages also seems to offer benefits when developing dementia. “Symptoms of dementia are delayed in individuals who have been lifelong bilinguals,” says Ellen Bialystok, Research Professor of Psychology and Walter Gordon York Research Chair of Lifespan Cognitive Development at York University (Canada), in a conversation with OpenMind.
In a study in which the professor and her team reviewed neuroimaging and behavioural studies that analysed bilingualism in adulthood, the scientists concluded that mastering two languages protects against cognitive deterioration by improving the cognitive reserve.
This concept refers to the protective effect of mental and physical activity carried out throughout life in the face of healthy aging. According to some studies, bilingualism can delay the onset of symptoms in people suffering from dementia by just over four years.
“These are activities we can engage in to keep our brains and minds healthy (music, social groups, exercise, etc.). Bilingualism is one such experience,” says Bialystok.
However, the researcher emphasizes that mastering several languages does not prevent dementia but, apparently, bilingual people live with the disease longer before the symptoms become evident and interfere with their independence.
Improve the recovery from a stroke
Bilingualism also seems to be beneficial when a person suffers a stroke. People who speak several languages are twice as likely to recover their normal cognitive functions after an attack of this type compared to those who speak only one.
This was revealed by an international study in which the researchers analysed the cases of 608 patients from the Institute of Medical Sciences of Nizam (India) who had suffered a stroke. After the attack, 40.5% of bilinguals recovered normal cognition, compared to 19.6% of monolinguals.
In view of these results, the authors suggest that having mastered two languages improves brain recovery after a stroke and that this advantage could be related to better cognitive reserve.
All these extra abilities are reflected in the brain. The frontal lobes, responsible for the executive functions, are the regions most related to bilingualism. A study from the University of Washington (USA) conducted in eleven-month-old babies from bilingual families (Spanish and English) and monolingual (only English) revealed differences in these areas.
Babies raised in bilingual households show brain activity associated with executive functioning as early as eleven months of age. Credit: Institute for Learning & Brain Sciences, University of Washington.
Using images of the brain, the researchers analysed how certain regions of the toddlers’ brains responded to sounds in Spanish and English. The prefrontal and orbitofrontal cortices (two areas of the frontal lobe) had more intense responses in bilingual babies compared to those who only heard and spoke one language.
Other studies have shown that grey matter is denser in the left inferior parietal regions of the cerebral cortex in people who speak two languages. In addition, bilingualism is associated with better maintenance of white matter during aging.
“Overall, bilinguals have developed different brain regions to perform tasks than the ones used by monolinguals,” Bialystok sums up. What remains a mystery is how these changes in brain ‘wiring’ improve the performance and cognitive reserve of people who speak two languages. One more enigma of these privileged minds.