Executive function and bilingualism in young and older adults.

Shanna Kousaie

doi:10.3389/fnbeh.2014.00250

Abstract

Research suggests that being bilingual results in advantages on executive control processes and disadvantages on language tasks relative to monolinguals. Furthermore, the executive function advantage is thought to be larger in older than younger adults, suggesting that bilingualism may buffer against age-related changes in executive function. However, there are potential confounds in some of the previous research, as well as inconsistencies in the literature. The goal of the current investigation was to examine the presence of a bilingual advantage in executive control and a bilingual disadvantage on language tasks in the same sample of young and older monolingual anglophones, monolingual francophones, and French/English bilinguals. Participants completed a series of executive function tasks, including a Stroop task, a Simon task, a sustained attention to response task (SART), the Wisconsin Card Sort Test (WCST), and the digit span subtest of the Wechsler Adult Intelligence Scale, and language tasks, including the Boston Naming Test (BNT), and category and letter fluency. The results do not demonstrate an unequivocal advantage for bilinguals on executive function tasks and raise questions about the reliability, robustness and/or specificity of previous findings. The results also did not demonstrate a disadvantage for bilinguals on language tasks. Rather, they suggest that there may be an influence of the language environment. It is concluded that additional research is required to fully characterize any language group differences in both executive function and language tasks.

Highlights

Executive functions, including inhibition, planning, and task switching, are important for everyday function
We found a main effect of Language Group (F(2,204) = 15.0, MSE = 9458.51, p < 0.01, ηp2 = 0.13), whereby RTs were longer in monolingual francophones than in monolingual anglophones and bilinguals
The analysis revealed that monolingual anglophones generated more words than monolingual francophones and bilinguals (main effect of Language Group F(2,210) = 4.47, MSE = 121.2, p = 0.01, ηp2 = 0.04)

Summary

Introduction

Executive functions, including inhibition, planning, and task switching, are important for everyday function. Studies have shown that being bilingual may result in more efficient, resilient, and robust executive control processes, leading to superior performance on executive function tasks in bilinguals relative to monolinguals (see Bialystok et al, 2009; Adesope et al, 2010). These language group differences have been found to be larger in older than young adults (Bialystok et al, 2004), and it has been suggested that bilingualism may delay the onset of Alzheimer’s disease symptoms (e.g., Bialystok et al, 2007, 2014; but see Chertkow et al, 2010; Zahodne et al, 2014). The goal of the current investigation was to further examine the bilingual advantage in monolingual anglophones, monolingual francophones, and French/English bilingual young and older adults

Methods

Results

Discussion

Conclusion