Researchers Identify Link between Bilingualism and Cognitive Efficiency

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An international team of researchers, including scholars from HSE University, has discovered that knowledge of a foreign language can improve memory performance and increase automaticity when solving complex tasks. The higher a person’s language proficiency, the stronger the effect. The results have been published in the journal Brain and Cognition.

Cognitive efficiency refers to the ability to use one’s mental resources optimally when learning or carrying out different tasks. It includes such processes as attention, memory, speech, and the capacity to switch between tasks. According to previous studies, speaking two or more languages enhances cognitive efficiency because it requires constantly switching between several linguistic systems without mixing them up.

Researchers from Russia, Norway, and Italy, together with scientists from the HSE Institute for Cognitive Neuroscience, examined how cognitive efficiency manifests in bilinguals. They conducted an experiment involving 45 Russian-speaking bilinguals aged 18 to 34 who were learning English. The participants completed a series of tests using the n-back task. This is a sequence of exercises presented as a computer game designed to test working memory: players must track a sequence of stimuli and determine when the current stimulus matches the one shown n steps earlier. The task has several difficulty levels—from 0 to 3, depending on how many steps back the comparison is made. In this experiment, the stimuli were Russian consonants: Б, Г, Ж, К, Л, М, П, Ф, Ч, Ш. The results were assessed by accuracy, reaction time, and the speed/accuracy ratio.

It turned out that participants with a higher level of English proficiency as their second language showed a smaller drop in accuracy and speed when completing high-difficulty tasks. At the same time, no differences were found when solving simpler tasks (n-back from 0 to 2).

Federico Gallo

‘Cognitive efficiency is the ability to do a lot while spending little. But to assess it, one must look not only at the ratio between completed tasks and resources spent. It is important to vary task difficulty and observe how the brain copes with the load,’ explained one of the study’s authors, Federico Gallo, Research Fellow at the HSE Cognitive Health and Intelligence Centre. ‘During the experiment, we saw that bilinguals maintain high working-memory performance—both in terms of speed and accuracy—even when task difficulty increases, which is a sign of cognitive efficiency.’

The researchers note that the strength of the positive effect of bilingualism increased as the cognitive load grew. ‘This can be explained by the fact that the participants were young adults—their cognitive abilities are naturally high due to their age. Therefore, when performing simpler tasks, bilingualism had no chance to show its effects, as the brain did not require additional resources. But when the load increased, we saw a different picture,’ Federico Gallo said.

More experienced bilinguals also displayed distinct patterns in the speed/accuracy trade-off depending on task difficulty. Among those with weaker second-language proficiency, the trade-off shifted towards accuracy at levels 1 and 2 (when they had to recall what appeared one or two steps earlier) and shifted back towards speed at level 3 (when participants recalled what appeared three steps earlier). In more advanced bilinguals, the shift towards accuracy occurred only at the 2-back level and persisted at the 3-back level. This indicates greater automatisation of working-memory processes in experienced bilinguals.

‘While some results were also tied to how early individuals acquired their second language, others—and the majority of the effects reported—were linked to second-language proficiency, independently of the age of acquisition. This suggests that is never too late to acquire a second language and obtain this type of cognitive benefits,’ Federico Gallo commented.