Does foreign language learning in older age improve executive function? A three-level meta-analysis

To elucidate the effects of foreign language learning initiated in older age on individuals' executive function, a three-level meta-analysis was conducted on 20 included studies (63 effect sizes). The results showed that foreign language learning in older age had a small but significant beneficial effect on executive function (g = 0.37, p < 0.001); in the high-quality “foreign language learning–active control” RCT subgroup, the effect was markedly attenuated (g = 0.11, p = 0.119), suggesting limited language-specific gains and that the overall effect may partly stem from the general cognitive stimulation properties of foreign language learning. Moderator analyses revealed that improvements in executive function were significantly moderated by linguistic distance, with greater linguistic distance associated with greater cognitive improvement; preliminary evidence indicated greater gains among older adults with cognitive impairment than among healthy individuals, but this conclusion was based on only 3 independent studies and requires further validation. In linear meta-regression, neither learning duration nor learning intensity had a significant moderating effect; further nonlinear analyses revealed a significant nonlinear moderating effect of learning intensity. Neither control type nor executive function subcomponents had significant moderating effects. In addition, support for the processing complexity effect hypothesis was significantly stronger than that for the interference inhibition effect hypothesis, and the results supported the bilingual executive processing advantage hypothesis rather than the bilingual inhibitory control advantage hypothesis. This study can provide a basis for developing low-cost nonpharmacological cognitive interventions and for cognitive health practices in older adults, while also laying a foundation for research on language learning across the lifespan and its cognitive effects.