The Role of Bilingualism in Executive Control, Working Memory, and Episodic Memory: Evidence from Polish-English adults

This study sought to examine how bilingualism modifies long-term memory mechanisms, specifically episodic memory as measured by paired associate learning and verbal fluency. Additionally, it investigated whether there is a bilingual advantage in executive control and working memory which has been inconsistently found in previous studies (i.e., Bialystok, Craik, & Luk, 2012; but see Paap & Greenberg, 2013). A systematic review was conducted as a part of this project with 22 eligible studies included in the meta-analytic considerations. Nineteen monolingual English adults and 28 Polish-English bilinguals were recruited to participate in three experiments. To assess their performance on episodic memory, a paired associate learning task was developed and piloted to ensure its integrity and reliability as an episodic memory measure. Results obtained in this thesis are largely inconsistent with the results obtained from the systematic review. Working memory but not executive control bilingual advantage was found in the meta-analysis. No bilingual advantage was found for either working memory or executive control in Experiment One. The meta-analysis revealed a bilingual advantage in episodic memory for recall and recognition, but this was not replicated in Experiment Two. Finally, Experiment Three did not find a bilingual advantage in episodic memory as measured by verbal fluency which is consistent with research findings concerning low proficiency bilinguals. Indeed, performance on episodic memory and executive control is constrained by level of bilingualism and frequency of English usage. Although no bilingual advantage was found in this study, there seem to be organisational differences in cognitive mechanisms between bilinguals and monolinguals. Also, it is important for future studies to ensure that bilingual sample is clearly defined and of the second language proficiency level that enables capturing a potential bilingual advantage in episodic memory, working memory, and executive control. The results are further discussed from the perspective of the findings from the systematic review of the available literature.