Bilinguals' and monolinguals' performance on a non-verbal cognitive control task: how bilingual language experience contributes to cognitive performance by reducing mixing and switching costs

Aims and objectives/purpose/research questions: The study investigated whether language experience predicts cognitive performance in bilingual and monolingual adults. As indicators of language experience, we focused on language context, typological proximity/distance between two languages and onset age of active bilingualism. As indicators of cognitive performance, we measured mixing costs and switching costs to gauge proactive and reactive control processes during a computerized non-verbal cognitive control task. Design/methodology/approach: Demographic and language data were collected with the Language and Social Background Questionnaire. Mixing and switching costs were subsequently obtained using a cued non-verbal switching task. Data and analysis: The background and switching-task data obtained from 60 bilinguals from non-English-speaking backgrounds and 24 English monolinguals residing in Australia were analysed using linear fixed-effects regression analyses. Findings/conclusions: The results showed that the use of two languages in a dual-language context was associated with reduced switching costs relative to monolingual and bilingual separated-language contexts and with reduced mixing costs only relative to a bilingual separated-language context. Among the bilinguals, lower mixing costs were also associated with an earlier onset age of active bilingualism and smaller typological distance between two languages. Originality: This study’s design included bilinguals as a target group and monolinguals as a control group, thus enabling the identification of possible mixing and/or switching cost advantages in bilinguals. By targeting young/middle-aged adults and considering a set of potentially relevant language experiences, this work was, therefore, well placed to provide clarity on findings for an age group that previously returned mixed and inconclusive results regarding a bilingual advantage. Significance/implications: Our findings reinforce the idea that particular dimensions of bilingual experience rather than bilingualism per se are linked to enhanced cognitive performance.