Preregistration documents for A Systematic Review of Cognitive Flexibility in Bilinguals vs Monolinguals

From very early on, papers like Bialystok, E. (1988) have explored and shown a link between bilingualism and cognitive control. Such theories encompass the core function of cognitive flexibility in reference to switching rules and the need to inhibit an ongoing task in order to be in control of the requirements of the next task (Liu et al., 2016). While existing research has explored the link between bilingualism and cognitive flexibility, it has largely failed to consider several contextual factors that may significantly influence the presentation of cognitive flexibility skills in individuals. Such factors could include the type of bilingualism (sequential or simultaneous), the age of language acquisition, native environment, cultural contexts such as multiculturalism or acculturation, and migrant generation. Failure to account for these variables in previous studies may not fully capture the diversity of cognitive outcomes among bilingual individuals. Moreover, inconsistencies in study design, sample characteristics, and the measures used to assess cognitive flexibility further complicate the interpretation of results. Through this systematic review, we aim to determine how existing literature accounts for individual differences in bilingualism, and to what extent it considers factors that might affect cognitive flexibility in adult bilinguals. Specifically, we will be looking into the following objectives: first, assessing quality indicators by examining methodological rigour (consistency in study design, sample characteristics, reliability of measures used to assess cognitive flexibility et cetera); second, to classify and evaluate studies based on different types of bilingualism (sequential versus simultaneous bilinguals), as well as age of language acquisition and contextual factors; and third, to explore how these classifications and individual differences influence cognitive flexibility outcomes. Through this review, we hope to gain a more precise understanding of cognitive profiles among bilinguals versus monolinguals in varied settings and provide clear directions for future research.