Gene-Environment Interactions in Bilingualism and Cognitive Flexibility in Linguistic Studies

Abstract

Bilingualism provides a unique window into the interplay between genetic predispositions and environmental experience in shaping cognitive flexibility. Evidence suggests that second-language acquisition can enhance executive function, particularly in task-switching, working memory, and attentional control, but these benefits are moderated by individual genetic variability. Polymorphisms in genes such as COMT, DRD4, BDNF, SLC6A20, CDH13, and ZNF804A influence neural mechanisms underlying language learning and cognitive flexibility. Gene-environment interaction frameworks-including differential susceptibility and plasticity models-highlight how enriched bilingual exposure can amplify or mitigate the effects of these genetic variants. Empirical studies demonstrate that the timing, intensity, and quality of bilingual language input interact with genetic factors to produce variability in cognitive outcomes. Integrating genetic, neurocognitive, and experiential data provides a more complete understanding of the mechanisms supporting bilingualism-related cognitive advantages. These insights have implications for educational policy, individualized learning strategies, and interventions targeting cognitive development across the lifespan.