Cognitive efficiency and expertise-dependent automaticity in the working memory performance of bilinguals

The concepts of cognitive efficiency (CE) and expertise-dependent automaticity are central to the understanding of cognitive adaptations related to bilingual experiences. This study examined their behavioral manifestations in bilingual young adults by manipulating the cognitive load of a working memory task; the possibility to manipulate the difficulty of a cognitive task is necessary to observe behavioral outcomes associated with CE and automaticity. To this end, participants completed an n-back task ranging in difficulty from 0-back to 3-back, with the 3-back condition being commonly recognized as being a highly cognitively demanding one. We aimed to determine whether degree of bilingual experience could predict performance outcomes - accuracy, reaction times, and the speed/accuracy tradeoff - reflecting bilingualism's putative dynamic impact on CE and automaticity in working memory. The results showed a positive relationship between degree of bilingual experience and working memory performance, particularly when the task-induced cognitive load increased. More experienced bilinguals demonstrated a smaller decline in performance when task difficulty intensified, a behavioral manifestation compatible with increased CE. Additionally, a relationship with expertise-dependent automaticity emerged, with the speed/accuracy tradeoff trajectory unfolding differentially across varying task difficulties at different degrees of bilingual experience.