Dimensions of bilingualism promoting cognitive control: impacts of language context and onset age of active bilingualism on mixing and switching costs

The study investigated the capacity of language experiences to predict cognitive performance of bilingual adults, with a special focus on participants' proactive (mixing costs) and reactive (switching costs) control processes. Using a Language and Social Background Questionnaire, demographic and language data were collected from a linguistically diverse group of 60 bilingual adults residing in Australia. The participants were then tested on a non-verbal switching task. The results of multiple regressions revealed that two of the language variables being examined accounted for the variance in the mixing and switching costs. In particular, reduced mixing costs were related to the use of two languages in a dual-language context and earlier onset age of active bilingualism; reduced switching costs were linked to a dual-language context only. These findings reveal that bilingual experiences contribute to shaping proactive and reactive control processes across cognitive domains.