Modulatory role of inhibition during language switching: Evidence from evoked and induced oscillatory activity

Abstract

Aims: The present study adopted the electroencephalogram (EEG) technique to investigate whether inhibition advantage could modulate different language switches, regardless of the time spent on second language learning. Design: The inhibitory control (IC) ability of 80 low-proficient Chinese (L1)-English (L2) bilinguals was assessed by the Simon task. Half of these bilinguals were then subdivided into 20 high- and 20 low-IC participants to perform switching between L1 and L2 (L1–L2 switching), and the other half were subdivided into 20 high- and 20 low-IC participants to conduct switching between L1 and Lnew (L1–Lnew switching). All participants were required to name pictures (picture naming task) in their L1 and L2/Lnew in language switching task. Data and analysis: Both response latencies and EEG data were obtained, and then evoked and induced oscillations were calculated using time–frequency analysis. Findings: The results of language switching showed similar naming latencies for L1 and L2/Lnew switch trials in the high-IC group, whereas the low-IC group showed larger naming latencies for L1 switch trials than L2/Lnew switch trials. In contrast, the high-IC group exhibited larger theta evoked and induced power for L2/Lnew switch trials than L1 switch trials at the lexical selection level, whereas the low-IC group did not. These findings indicate that inhibition advantage helps the high-IC group to suppress effectively the non-target word via recruiting bottom-up (evoked oscillation) and top-down (induced oscillation) processes. Innovation: The present study was a first attempt to provide evidence that theta oscillation indicates cross-language interference at the lexical selection level. Significance: Inhibition plays a modulatory role in language switching, which is independent of the time spent on second language learning, and such role involves bottom-up (i.e., evoked oscillation) and top-down (i.e., induced oscillation) processes which were mainly evident at the lexical selection level.

Symmetries of bilingual language switch costs in conflicting versus non-conflicting contexts

“…Moreover, other studies have shown an overlap in the mechanisms between language control and domain-general control (e.g., Declerck, Grainger, Koch & Philipp, 2017; Prior & Gollan, 2013). These findings suggest that variances in inhibitory control ability between individuals play an important role in modulating language switch costs and that they should be considered within the ICM framework (Liu et al, 2014; Liu et al, 2015; Liu et al, 2016).…”

“…More recently, researchers have posited that the individual capacity of cognitive control also plays an analogous role in modulating language switch costs (Liu et al, 2015(Liu et al, , 2016. Liu et al (2015) found that the language switch costs of non-proficient bilinguals with high IC were symmetrical while that of nonproficient bilinguals with low IC were not.…”

“…More recently, researchers have posited that the individual capacity of cognitive control also plays an analogous role in modulating language switch costs (Liu et al, 2015(Liu et al, , 2016. Liu et al (2015) found that the language switch costs of non-proficient bilinguals with high IC were symmetrical while that of nonproficient bilinguals with low IC were not. Their findings supplemented the IC model from a different perspective, implying not only that inhibition may play an important role during language switching but also that bilinguals with low proficiency can switch effectively between different languages if their capacity of inhibitory control is greatly enhanced.…”

“…To account for the discrepancy in previous studies, Liu et al (Liu, Liang, Zhang, Lu & Chen, 2015; Liu, Liang, Dunlap, Fan & Chen, 2016) argued that the language switch cost is not only affected by the proficiency levels of bilinguals’ L1 and L2; variances in the domain-general cognitive control ability between bilingual participants could also account for their performance in language-switching tasks. Their studies showed that for non-proficient bilinguals who have different levels of proficiency in L1 and L2, those with high inhibitory control (i.e., the high-IC group) showed symmetrical switch costs and those with low inhibitory control (i.e., the low-IC group) showed asymmetrical switch costs.…”

Contributions of nonlinguistic task-shifting to language control in bilingual children

“…Furthermore, within L1, competing lexical representations may have been activated because they were related to the target word or were evoked by the visual stimulus, and the activation level of the target L1 lexical representation must exceed that of its L1 competitors to ensure production of the correct lexical item. Although it may be possible for domain-general control processes to be recruited during the process of lexical selection (e.g., Liu, Rossi, Zhou & Chen, 2014; Liu, Liang, Zhang, Lu & Chen, 2015), language-specific mechanisms may be more likely to regulate activation levels of lexical representations within a language.…”