Language-specific cognitive flexibility is related to code-switching habits and interactional context; domain-general cognitive flexibility is not

Individualistic experience with code-switching has often been found to modulate bilingual executive functioning, though the direction of these effects is variable. The present study investigated whether French-English code-switching in a primarily dual-language context (the environment which requires the most control processes) may lead to increased cognitive flexibility. Sustained (mixing) and transient (switching) cognitive flexibility was examined in a domain-general task and a novel language-specific task (i.e. a cued bilingual lexical decision task). First, mixing and switching effects in the domain-general task were not reliably predicted by the participants' code-switching habits. Second, though the sample displayed minimal switching effects and a mixing benefit in the language-specific task, these were positively predicted by the participants' deliberate code-switching. By contrast, predictors related to dense code-switching were negatively related to the participants' language-specific sustained cognitive flexibility. Altogether, our findings indicate that any training instilled by dual-language code-switching is restricted to language-specific cognitive flexibility.