Bilingualism: A Three-Domain Meta-Analysis in Adulthood and Aging
Description
The attached supplementary materials contain three related sets of data supporting the systematic review and meta-analysis: Appendix 2: Study characteristics and extracted variables This appendix provides a detailed study-level extraction table. For each included study, it records information such as the sample size and comparison groups, participants’ age, bilingual proficiency, duration and frequency of bilingual language use, languages spoken, tasks or measures employed, reported outcomes, and the domain in which a bilingual advantage, disadvantage, or null result was observed. The studies cover behavioral, lexical, executive-function, neuroimaging, cognitive-reserve, stroke, and dementia-related outcomes. Appendix 3: Effect-size data This appendix reports the quantitative data used in the meta-analysis. It identifies the primary outcome selected from each study, the type of effect-size calculation, the bilingual and monolingual sample sizes, and the estimated standardized effect, generally expressed as Hedges’ g. Positive values are coded as favoring bilinguals, whereas negative values indicate poorer bilingual performance. The table includes both advantages and disadvantages across outcomes such as working memory, conflict processing, picture naming, switching, metacognitive efficiency, and neural measures. Appendix 5: PRISMA 2020 checklist This appendix documents how the review addresses the PRISMA 2020 reporting requirements. For each checklist item, it provides the reporting status, supporting evidence or a precise manuscript reference, explanatory notes, and the relevant manuscript location. It covers areas including the review objectives, eligibility criteria, search strategy, screening process, data extraction, outcome definitions, risk-of-bias assessment, effect measures, and synthesis procedures.