2018 Sat Poster 6538
Saturday, November 3, 2018 | Poster Session II, Metcalf Small | 3:15pm
Early onset of bilingualism and frequent language switching confers advantage in executive functioning: A study of two bilingual populations
K. Tamasi, Q. Yow
In recent years, evidence has been accumulated regarding the existence of a bilingual advantage in executive functioning (e.g. Bialystok, Craik, Luk, 2012; Hernandey, Martin, Barceló, & Costa, 2015; Yow & Li, 2015). However, studies rarely investigate the source of such an advantage. This study explores what indicators of bilingualism – onset of bilingualism, language usage, language proficiency, and language switching characteristics – facilitate executive functioning in young adults.
Two bilingual populations, Singaporean and non-Singaporean individuals living in Singapore (71 Singaporeans: 22 women, Mage=24.66 years, SDage=4.52, and 60 non-Singaporeans: 12 women, Mage =26.57 years, SDage=4.20; all affiliates at the authors’ university), were investigated with a battery of tasks probing their executive functioning skills: number-letter switching task (set-shifting skills), 2-back task (working memory updating), go/no-go task (response inhibition), and visual search task (perceptual attention). Previous research using principal component analysis has determined that even though both bilingual populations study and work under similar conditions in Singapore, their different language background (e.g., significant differences in onset age of bilingualism and frequency in language switching) warrants separate analyses (Tamási, Zhang, & Yow, 2018). In this study, we used likelihood ratio tests of linear mixed effects models (Bates, 2005; Pinheiro, Bates, Debroy, & Sarkar, 2007) to identify the most parsimonious ones, and two variables, namely onset of bilingualism and language switching frequency, emerged as significant language predictors of executive functioning in both bilingual populations (see Table 1A and 1B). Firstly, for onset of bilingualism, early bilinguals are expected to have better executive functioning skills than late bilinguals as they can reap more benefits by having more experience with bilingualism (Luk, De Sa, & Bialystok, 2011; Yow & Li, 2015). Accordingly, our results showed that both Singaporean and non-Singaporean early bilinguals exhibited faster visual search performance than late bilinguals. Onset of bilingualism further predicted the performance of the Singaporean group in the task switching task and 2-back task such that early acquisition of second language predicted faster reaction times. Secondly, language-switching habits may confer cognitive advantages as it might have honed the ability to seamlessly switch between tasks and continually adjust to task requirements (Rodriguez-Fornells et al. 2012). Our results showed indeed, that frequent language switching predicted faster reaction times in the go/no-go task for Singaporeans and faster visual search performance for non- Singaporeans.
Overall, despite significant differences in the language background between Singaporean and non- Singaporean bilinguals, the language predictors affecting their executive functioning skills are similar: the same language variables predicted executive functioning skills for both bilingual populations, albeit slightly different performance outcomes. However, more aspects of executive functioning performance have been predicted in the Singaporean than the non-Singaporean population. Such an asymmetry may have arisen due to the Singaporean group being more homogeneous in language background and experience than the non-Singaporean group. These findings raise the possibility that the likelihood of finding evidence for bilingual advantage increases when participants share a similar language background, while less evidence emerges with more heterogeneous populations. Whether this finding generalizes over to other bilingual communities is an issue worth studying further.
References
Bates, D. (2005). Fitting linear mixed models in R. R News, 5 (1), 27–30.
Bialystok, E., Craik, F. I., & Luk, G. (2012). Bilingualism: consequences for mind and brain. Trends in Cognitive Sciences, 16(4), 240-250.
Hernández, M., Martin, C. D., Barceló, F., & Costa, A. (2013). Where is the bilingual advantage in task- switching?. Journal of Memory and Language, 69(3), 257-276.
Luk, G., De Sa, E., & Bialystok, E. (2011). Is there a relation between onset age of bilingualism and enhancement of cognitive control? Bilingualism: Language and Cognition, 14(4), 588-595.
Pinheiro, J. C., Bates, D., DebRoy, S., & Sarkar, D. (2007). Linear and nonlinear mixed effects models. R-Package-version, 3, 57.
Rodriguez-Fornells, A., Kramer, U., Lorenzo-Seva, U., Festman, J., & Münte, T. F. (2012). Self- assessment of individual differences in language switching. Frontiers in Psychology, 2, 388.
Tamási, K., Zhang, L., Yow, W. Q. (2018). Early onset of bilingualism and frequent language switching confers executive control advantage: A Principal Component Analysis of two bilingual populations. Proceedings of the 7th Conference on Cognitive and Behavioral Psychology.
Yow, W. Q., & Li, X. (2015). Balanced bilingualism and early age of second language acquisition as the underlying mechanisms of a bilingual executive control advantage: why variations in bilingual experiences matter. Frontiers in Psychology, 6.