No cognitive advantage of being bi- or multilingual

Speaking multiple languages helps us to communicate with more people: this is quite logic. But what are the advantages bilinguals seem to have on monolinguals on cognitive tasks, so not directly related to language use?

This is, alas, one of the many myths related to being bi- or multilingual that need to be debunked…

Since psychologist Ellen Bialystok and her team showed an “enhanced executive control” in bilinguals, which was linked to better academic performance and delays the onset of dementia, many studies have been conducted on this topic.

These studies are mostly based on a series of executive function tasks. Executive functions “consist of a set of general-purpose control processes that are central to the self-regulation of thoughts and behaviors and that are instrumental to accomplishing goals” (Paap, Johnson, Sawi, 266: 2015). Executive function tasks focus on inhibition, planning, and task switching which are all important for everyday function: Stroop task, Simon task, sustained attention to response task (SART),the Wisconsin Card Sort Test (WCST), the digit span subtest of the Wechsler Adult Intelligent Scale; some included language tasks such as the Boston Naming Test (BNT), the category and letter fluency tests, switching tests and others.

Investigating age of acquisition, L2/L1 proficiency, proportion of language use, language similarity, and other aspects of bilingualism did not lead to any consistent results (von Bastian, Souza, Gade, 2015): all these studies do not demonstrate an unequivocal advantage for bilinguals on executive function tasks and raise many questions about their reliability, robustness and specificity of previous findings.

The fact that “80% of the tests for bilingual advantages conducted after 2011 yield null results and those resulting in significant bilingual advantages tend to have small sample sizes” brought Kenneth R. Paap & Oliver Sawi (2014) to re-analyze the approaches and “based on an array of evidence (they) have made a case that it is likely that bilingual advantages in executive functioning do not exist“. Angela de Bruin and her team reach the same conclusion in their meta-analytic review of 2018: “the available evidence does not provide systematic support for the widely held notion that bilingualism is associated with benefits in cognitive control functions in adults.”

In her meta-analysis of studies that linked bilingualism and cognition, Angela De Bruin and her team (2015) found out that “sixty-eight per cent of the studies that demonstrated a bilingual advantage found a home in a scientific journal, compared to just twenty-nine per cent of those that found either no difference or a monolingual edge”. They came to the conclusion that: “there is a distorted image of the actual study outcomes on bilingualism, with researchers (and media) believing that the positive effect of bilingualism on nonlinguistic cognitive processes is strong and unchallenged.” After conducting a successive test on three different groups, using four tasks aimed to find a cognitive advantage of being bilingual they came to the conclusion that the enhanced ability to switch between tasks is the result of simply learning.

There are several studies and articles published about this topic in the past years: all confirm that bilingualism is not intrinsically linked to better or enhanced cognitive functions.

That being bilingual helps to protect the brain against dementia, is simply not true.

Being bilingual might delay the onset of symptoms or diagnosis of dementia by several years, but doesn’t protect from it. As Eva Juarros-Daussà from the Department of Frisian Language and Culture at the University in Groningen states: “the dementia studies have the same flaws than the cognitive task ones: there is no baseline data of cognitive performance previous to illness, and thus the comparison is not really reliable”.  Neurological data on this matter also doesn’t yield the expected results: “there is currently a disconnect between the favored executive functioning component in the behavioral literature (monitoring/mental flexibility) and the contrasts used most frequently in the neuro-imaging work that typically compare statistical maps between congruent and incongruent trials” (Paap et al 2015, 275).

At this stage of research, there is a need for a theory on how two or more languages are co-ordinated and specify which of the “control mechanisms employ domain-general executive functioning”.

According to Paap, Johnson and Sawi (2015) research on cognitive functioning and bi-/multilingualism should focus on the following questions:

– is there a specific type  of bilingual experience that is most important to enhancing that component of executive functioning?

– does this critical experience play the lead role in predicting which bilingual groups should have better executive functioning and be better than monolinguals?

– how do these groups need to be matched with SES, immigrant status, culture etc. using operationally defined measures?

only to name a few… 

The current conclusion from these studies is that there is little evidence that bilingualism protects against cognitive decline; if there are any kind of bilingual advantages to executive functioning, they are restricted to specific aspects of bilingual experience that enhance only specific components of the executive function and these constraints, if they exist, need yet to be determined.

Like Dr. Eva J. Daussà points out: “the most salient benefits of multilingualism are not necessarily at the general cognitive level (other than those brought about by the extra learning), but at the psychosocial level: multilinguals are used to look at issues, people, and things from multiple perspectives, and that makes them more flexible in their thinking, which is highly conducive to better problem solving skills, deeper empathetic intelligence, and better social skills.”




A. De Bruin, T. H. Bak, S. della Sala (2015), Examining the effects of active versus inactive bilingualism on executive control in a carefully matched non-immigrant sample, in Journal of Memory and Language, Vol 85, November 2015, 15-26.

A. De Bruin, B. Treccani, S. Della Sala (2015), Cognitive advantage in blingualism: an example of publication bias, Psychological Science, 26(1), 99-107.

C.C. von Bastian, A.S. Sousa, M. Gade (2015), No evidence for bilingual cognitive advantages: A test of four hypotheses, Journal of Experimental Psychology General 145(2).

S. Kousaie, Ch. Sheppard, M. Lemieux, L. Monetta, V. Taler (2014), Executive function and bilingualism in young and older adults, Frontiers in Behavioral Neuroscience, 8. (doi: 10.3389/fnbeh.2014.00250)

M. Lehtonen, A. Soveri, A. Laine, J. Järvenpää, A. de Bruin, J. Antfolk (2018), Is bilingualism associated with enhanced executive functioning in adults? A meta-analytic review  in Psychological Bulletin, Vol 144(4), April 2018, 394-425

C.M. MacLeod (1991), Half a century of research on the Stroop effect: An integrative review, Psychological Bulletin, 109, 163-203.

K. R. Paap, O. Sawi (2015), Bilingual advantages in executive functioning: problems in convergent validity, discriminant validity, and the identification of the theoretical constructs, Frontiers in Psychology, 2015, 2. (doi: 10-3389/fpsyg.2014.00962)

J. R. Stroop (1935), Studies of interference in serial verbal reactions. Journal of Experimental Psychology, 18, 643-662. Read here on Classics in the history of psychology.




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