Trajectories of verbal fluency and executive functions in multilingual and monolingual children and adults: A cross-sectional study

Abstract

The development of verbal fluency is associated with the maturation of executive function skills, such as the ability to inhibit irrelevant information, shift between tasks and hold information in working memory. Some evidence suggests that multilinguistic upbringing may underpin disadvantages in verbal fluency and lexical retrieval, but can also afford executive function advantages beyond the language system including possible beneficial effects in older age. This study examined the relationship between verbal fluency and executive function in 324 individuals across the lifespan by assessing the developmental trajectories of English monolingual and multilingual children aged 7 to 15 years (N=154) and adults from 18 to 80 years old (N=170). The childhood data indicated patterns of improvement in verbal fluency and executive function skills as a function of age. Multilingual and monolingual children had comparable developmental trajectories in all linguistic and non-linguistic measures used in the study with the exception of planning, for which monolingual children showed a steeper improvement over the studied age range relative to multilingual children. For adults, monolinguals and multilingual participants had comparable performance on all measures with the exception of non-verbal inhibitory control and response times on the Tower of London task: monolinguals showed a steeper decline associated with age. Exploratory factor analysis indicated that verbal fluency was associated with working memory and fluid intelligence in monolingual participants but not in multilinguals. These findings raise the possibility that early acquisition of an additional language may impact on the development of the functional architecture serving high-level human cognition.

Modulatory effects of SES and multilinguistic experience on cognitive development: a longitudinal data analysis of multilingual and monolingual adolescents from the SCAMP cohort

“…This result is particularly intriguing because differences in working memory processing between bilingual and monolingual children matched by SES are not usually found, (e.g. Filippi et al 2015 , 2020 ; Filippi, Ceccolini, and Bright 2021 ). However, as mentioned in the introduction, these studies did not contrast different levels of SES.…”

“…These tests are generally used in bilingual research (e.g. Filippi et al 2019 ; Filippi, D’Souza, and Bright 2019 , Filippi et al 2020 ; Filippi, Ceccolini, and Bright 2021 ; Seçer 2016 ) to test theoretical frameworks, such as the Inhibitory Control Model (Green 1986 , 1998 ). The model predicts that a domain-general inhibitory control mechanism is required in order to resolve the competition from both languages, suppress the language not in use and select the target one.…”

“…In cognitive psychology and psycholinguistics, multilingual and monolingual speakers have been extensively compared on measures of verbal performance, with tasks measuring linguistic skills, such as vocabulary acquisition (e.g. Oller, Pearson, and Cobo-Lewis 2007 ) or verbal fluency (Filippi, Ceccolini, and Bright 2021 ), and non-verbal performance, with a focus in particular on components of executive function (i.e. inhibition of irrelevant information, switching and shifting tasks and working memory processes – see Bialystok 2017 , for an extensive review of the literature).…”

“…Commonly, three key measures are used to capture SES in most studies: level and type of education, occupational status and household income (e.g. Filippi et al 2020 ; 2021 )…”

“…Large scale cross-sectional studies in which the monolingual and bilingual participants’ SES was rigorously controlled and homogeneous across the two groups have not provided any statistically significant evidence for a bilingual advantage in executive function (e.g. Filippi et al 2020 , 2021 ). The homogeneity in levels of SES (i.e.…”