A meta-analysis of Stroop task studies on bilinguals’ emotional word processing

This meta-analysis examines emotional Stroop interference in bilinguals, a literature characterised with inconsistent findings on age of acquisition (AoA), emotional valence, and L2 proficiency. Following PRISMA 2020 guidelines, a systematic search across six electronic databases identified 10 studies (12 independent effect sizes, N = 450). Random-effects meta-analysis yielded a non-significant pooled effect characterized by extreme heterogeneity. Mixed-effects moderator models identified age of L2 acquisition as the critical boundary condition: early-acquired bilinguals exhibited reliable interference, whereas late-acquired bilinguals did not. Proficiency assessment method and valence eligibility were non-significant, suggesting that superficial methodological differences do not account for the literature’s variability. Formal stimulus-type analysis was precluded by a near-absence of emotion-label studies. These findings indicate that emotional Stroop interference in bilinguals is conditional on neurodevelopmental timing, supporting neurodevelopmental models of integrated language–emotion networks. The results underscore the need for standardised paradigms and more diverse bilingual samples in future primary research.