Post written by François Grosjean.

Over the last years, we have been impressed by, and have reported regularly on, what has been called, "the bilingual advantage". It is the proposal that the experience of using two or more languages - selecting one, while inhibiting the other(s) - strengthens executive control (also called executive function). It is involved in such complex cognitive processes as attention, inhibition, monitoring, and so on (see here). This bilingual advantage, which can be observed in various experimental tasks used with children and adults, has been reported to also have an impact on cognitive reserve. This is a protective mechanism against age-related cognitive decline and has been reported to delay the symptoms of dementia in bilinguals by a number of years (see here and here).

As Aneta Pavlenko wrote in an earlier post, the early findings "captured our hearts and minds" and were a change from concerns about the disadvantages of bilingualism found in the literature in the first half of the last century (see here). But she asked whether the pendulum had swung too far in favor of bilinguals and she reported on a heated debate that had started on this issue. Basically, many research teams, working with both children and adults, could not replicate the effect and doubted its veracity.

In the middle of last year, researchers Kenneth Paap, Hunter Johnson and Oliver Sawi published a very critical review paper of the field for the prestigious brain sciences journal, Cortex. In it, they question the very existence of the bilingual advantage and summarize their findings in the following way: "It is likely that bilingual advantages in EF (executive functions) do not exist. If they do exist they are restricted to specific aspects of bilingual experience that enhance only specific components of EF. Such constraints, if they exist, have yet to be determined."

Instead of simply publishing the paper, and letting it have the life of an ordinary article, the editors of Cortex asked 21 research teams in the area to write comments on it in a "Bilingualism forum". The short texts which have just appeared make for interesting reading and show how complex the debate really is. First, several authors express their despondency at the situation this particular field is in now. For example, Eric-Jan Wagenmakers from the University of Amsterdam writes: "...even the most dispassionate reader will feel depressed at the suggestion that the collective research effort on bilingual advantages in executive functioning has been a waste of time, effort, and resources. The presence of such research waste has profound negative ramifications that extend well beyond the research topic at hand...".

One thinks here of the impact this will have on the scientific press that informs the layperson of advances in language research but also on the many websites and blogs that prone bilingualism and biculturalism and that hailed the earlier seminal findings, as we have done. Virginia Mueller Gathercole of Florida International University states this clearly, "One unspoken issue is undoubtedly some concern over the possible reversal of the growing positive press regarding bilingualism that the research on executive functions has engendered."

The list of problems that emerge from the comments is extensive. It covers the publication bias that seemed to prevail (failures to replicate the original studies were either not proposed to journals or were not accepted) as well as problems with the experiments themselves such as the use of tasks that lack convergent validity, the existence of groups of participants that were far too small, the use of questionable statistics, reporting only on the studies that gave positive results, etc.

Two problematic issues are repeated over and over again. The first concerns the lack of a clear explanation of how bilingualism affects executive control. For example, Barbara Treccani and Claudio Mulatti write: ".... one of the most serious faults of the literature on this topic (is) the lack of a clear, sound, well-grounded and broadly endorsed theory about how the mechanisms responsible for the management of the two languages would affect executive functions. The advocates of the bilingual advantage .... took for granted the existence of some relationship between the mechanisms that allow a person to handle two languages and those underlying the selection and control of other types of processes. However, the exact nature of this relation is usually not well specified and it is actually far from being clear."

The other problem, already mentioned by researchers such as Virginia Valian, is that numerous factors affect the development and maintenance of executive control such as intelligence, education, lifestyle including social and leisure activities (playing music or exercising), having an active social life, and so on. The whole problem of causality is posed therefore, and Raymond Klein even ventures that: " is just as likely that individuals with better executive functions were better able to master two languages".

Should this line of research be abandoned and should researchers move on to something else? No, reply several commentators who then propose solutions for future research. The bilingual abilities of participants could be assessed far better, monolinguals and bilinguals should be matched on even more variables, different tasks should be used so as to obtain converging evidence, appropriate and sophisticated statistics should be called upon, failures to replicate a finding should be accounted for, etc. In addition, longitudinal studies should be encouraged. As Ping Li and Angela Grant of Pennsylvania State University write, "Longitudinal designs allow us to track the same individual, regardless of his or her prior language history or cognitive ability, across a period of time from no bilingual experience to low bilingual proficiency to high bilingual expertise. Simultaneously, cognitive control abilities can be measured at various time points across this period." We report on one such study in an earlier post (see here) that did indeed show the bilingual advantage.

The last word can be given to representatives of two research teams. Evy Woumans and Wouter Duyck write, "...the discussion should not be about whether the bilingual advantage exists or not, but about what factors moderate its manifestation." As for Jared Linck, he states: "My expectation is that researchers will develop more specific hypotheses and employ refined methods, which will provide a more nuanced picture of the complex connections between cognitive processes and language experience."

While this continuing research is taking place, and we await the results, we may want to study the many other advantages there are of being bilingual (see here). Research on "the bilingual advantage" could then join a far broader enterprise, the scholarly study of the many benefits of living with two or more languages!

For a full list of "Life as a bilingual" blog posts by content area, see here.

Photo of a close up of an English dictionary page from Shutterstock.


Paap, Kenneth R., Johnson, Hunter A.,& Sawi, Oliver (2015). Bilingual advantages in executive functioning either do not exist or are restricted to very specific and undetermined circumstances. Cortex, 69, 265-278.

Bilingualism Forum (2015). Cortex, 73, 330-377.

Valian, Virginia (2015). Bilingualism and cognition. Bilingualism: Language and Cognition, 18, 3-24.

François Grosjean's website.

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