The effects of bilingualism on executive functions and cognitive reserve in young adults

Aims and objectives: This study aims to investigate differences in executive functions and cognitive reserve (CR) between bilingual and monolingual young adults. Methodology, data, and analysis: Participants included 32 bilinguals, who acquired both languages before age 10 and use them daily in various contexts, and 33 monolinguals matched for age, education, and gender. Executive functions were assessed through a comprehensive battery of tests measuring cognitive flexibility, inhibitory control, working memory, and abstract reasoning. CR was estimated using an irregular word reading test and the CR index questionnaire (CRIq). Findings: Results revealed that bilinguals outperformed monolinguals across tasks measuring different executive functions (cognitive flexibility, inhibitory control, and working memory), with these differences yielding medium effect sizes. Although no major significant differences between groups were observed in CR, except for the Education subscale of CRIq, where bilinguals showed higher scores, the impact of CR was not uniform. Notably, linear regression analyses revealed that CR was significantly associated with several subdomains of executive functions within the bilingual group, whereas these associations were circumscribed to working memory and inhibitory control in monolinguals. Originality and implications: These findings contribute to the growing body of evidence supporting the cognitive benefits of bilingualism, particularly in relation to executive functioning. The observed relationship between CR and executive function in bilinguals highlights a potential mechanism through which bilingualism might contribute to CR. Further research is needed to better understand the underlying mechanisms under which bilingualism contributes to the enhancement of CR.