Can Machines Find the Bilingual Advantage? Machine Learning Algorithms Find No Evidence to Differentiate Between Lifelong Bilingual and Monolingual Cognitive Profiles

Abstract

Bilingualism has been identified as a potential cognitive factor linked to delayed onset of dementia as well as boosting executive functions in healthy individuals. However, more recently, this claim has been called into question following several failed replications. It remains unclear whether these contradictory findings reflect how bilingualism is defined between studies, or methodological limitations when measuring the bilingual effect. One key issue is that despite the claims that bilingualism yields general protection to cognitive processes (i.e., the cognitive reserve hypothesis), studies reporting putative bilingual differences are often focused on domain specific experimental paradigms. This study chose a broader approach, by considering the consequences of bilingualism on a wide range of cognitive functions within individuals. We utilised 19 measures of different cognitive functions commonly associated with bilingual effects, to form a “cognitive profile” for 215 non-clinical participants. We recruited Welsh speakers, who as a group of bilinguals were highly homogeneous, as means of isolating the bilingualism criterion. We sought to determine if such analyses would independently classify bilingual/monolingual participant groups based on emergent patterns driven by collected cognitive profiles, such that population differences would emerge. Multiple predictive models were trained to independently recognise the cognitive profiles of bilinguals, older adults (60-90 years of age) and higher education attainment. Despite managing to successfully classify cognitive profiles based on age and education, the model failed to differentiate between bilingual and monolingual cognitive ability at a rate greater than that of chance. Repeated modelling using alternative definitions of bilingualism, and just the older adults, yielded similar results. In all cases then, using our “bottom–up” analytical approach, there was no evidence that bilingualism as a variable indicated differential cognitive performance – as a consequence, we conclude that bilinguals are not cognitively different from their monolingual counterparts, even in older demographics. We suggest that studies that have reported a bilingual advantage (typically recruiting immigrant populations) could well have confounded other key variables that may be driving reported advantages. We recommend that future research refine the machine learning methods used in this study to further investigate the complex relationship between bilingualism and cognition.

Exploring the Effect of Late, Unbalanced Bilingualism on Cognitive Control

“…There were not any significant bilingual advantages in the Stroop task. This was in line with certain other studies that did not find systematic evidence for cognitive advantages of bilingualism (Antoniou, 2019;Jones, Davies-Thompson, & Tree, 2021;Laketa, Studenica, Chrysochoou, Blakey, & Vivas, 2021;Paap, Johnson, & Sawi, 2015).…”

An emotional advantage of multilingualism

“…In recent years, several meta-analyses on bilingual advantages yielding heterogeneous results with regard to different cognitive functions (e.g., Adesope et al, 2010;Donnelly et al, 2019;Grundy & Timmer, 2017;Gunnerud et al, 2020;Lehtonen et al, 2018;Lowe et al, 2021;Ware et al, 2020) have been added to an ongoing and still vivid debate. Recent studies also contribute to this inconclusive situation: some researchers find a cognitive advantage (Czapka et al, 2020;Grote et al, 2021), while others do not report any advantages of multilingualism (Bellegarda & Macizo, 2021;Jones et al, 2021;Laketa et al, 2021;Liu et al, 2022;Nicoladis et al, 2018;Shokrkon & Nicoladis, 2021) or report differential results depending on the measures and group characteristics (Gillet et al, 2021). Whether a cognitive advantage of multilingualism with respect to "narrow" cognitive functions can be found seems to depend on the specific function under investigation, individual and social conditions of multilingualism, and the setting in and task with which they are measured.…”

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“…Subjects are required to listen to the numbers announced on an audiotape, then write down the two letters preceding a specified number [124,[128][129][130][131][132][133].…”