Bilingualism and Executive Functions: A Review of Evidence Across the Lifespan

The cognitive consequences of bilingualism have attracted sustained scholarly attention, particularly regarding whether regular use of two languages enhances executive functions (EF). While a substantial body of research reports a bilingual advantage in cognitive control, recent replication attempts and large-scale studies have produced inconsistent or null findings, giving rise to an ongoing debate. This review synthesizes influential empirical and neurocognitive studies examining bilingualism and executive functions across the lifespan, including children, young adults, and older adults. It first outlines theoretical accounts such as the Bilingual Executive Processing Advantage hypothesis, then reviews commonly employed experimental paradigms in non-verbal cognitive processing, including the Simon, Stroop, Flanker, and Attention Network Test, alongside neuroimaging approaches such as fMRI. The review demonstrates that evidence for bilingual cognitive advantages varies considerably by age group, task type, and methodological design, with effects more frequently observed in children and older adults than in young adults. Finally, the paper discusses key modulating factors that may account for conflicting findings, including individual differences, task sensitivity, sample size, and experimental variability. It is argued that the absence of consistent evidence does not negate bilingual advantages but instead highlights the need for more fine-grained, methodologically rigorous research. This review contributes to the ongoing debate by offering an integrative perspective on when, how, and under what conditions bilingualism may influence executive functioning.