The finding has been confirmed in an experiment by researchers from the URV, the University of Tromsø – The Arctic University of Norway and the Norwegian University of Science and Technology, who propose a new approach to the debate on the advantages and disadvantages of bilingualism: a good performance in one area of linguistic ability may mean lower accuracy or speed in another, and vice-versa

The impact of bilingualism or plurilingualism on neural connectivity, brain activity, and behaviour is an issue that neuroscientists, psychologists, and linguists have been researching for decades because it generates intense debate about the pros and cons of bilingualism. Now, an experiment conducted by researchers at the Universitat Rovira i Virgili, Tromsø University – The Arctic University of Norway and the Norwegian University of Science and Technology has studied the responses of bilingual and monolingual people when they read grammatical illusions, a category of manipulative discourse that deceives the mind by leading it to accept constructions that make no sense. The results of the experiment have necessarily changed the debate on bilingualism.

A total of 276 people took part in the study: half were monolingual in Greek and the other half were bilingual in Greek and a Germanic language. They had to state whether the grammatical constructions presented to them were correct, incorrect, or neither correct nor incorrect. The analysis of the results showed that the bilingual participants obtained a higher percentage of correct answers, but also needed more time to detect if there were any anomalies.

More specifically, bilinguals detected 56% of the grammatical illusions, whereas monolinguals detected only 39%. This means that bilingual people are better able to detect manipulations in a discourse. However, they need more time to come up with an answer, especially when they see that what is presented to them may not be correct. In the test, they took an average of 2 milliseconds to state that a grammatical construction was “correct” and 70 milliseconds to state that it was “incorrect”.

The results have been published in the scientific journal PLOS ONE and the researchers Evelina Leivada (URV), Natalia Mitrofanova (University of Tromsø – The Arctic University of Norway) and Marit Westergaard (University of Tromsø – The Arctic University of Norway and the Norwegian University of Science and Technology) emphasise that the need to change the focus of the debate around the advantages and disadvantages of bilingualism.

“Better performance in one domain is offset by decreased accuracy or speed when performing a task in another; therefore, we need to replace the concepts of advantage and disadvantage with the concept of multilingual adaptive compensation. In other words, the cognitive abilities of bilinguals can increase their ability to detect erroneous constructions, but this is part of a larger set of effects resulting from their bilingualism, not all of which are necessarily advantageous”, concludes Evelina Leivada, researcher at the URV’s Department of English and German Studies.

Reference: Leivada E, Mitrofanova N, Westergaard M (2021) Bilinguals are better than monolinguals in detecting manipulative discourse. PLoS ONE 16(9): e0256173. https://doi.org/10.1371/journal.pone.0256173.