Dynamics of inhibitory control during bilingual speech production: An electrophysiological study

Abstract

Bilingual speakers have to control their languages to avoid interference, which may be achieved by enhancing the target language and/or inhibiting the nontarget language. Previous research has provided evidence that bilinguals may use inhibition (e.g., Jackson, Swainson, Cunnington, & Jackson, 2001), which is reflected in the N2 component of the event-related potential (ERP). In the current study, we investigated the dynamics of inhibitory control by measuring the N2 during language switching and repetition in picture naming. We recorded the EEG of 30 unbalanced Dutch-English bilinguals in a cued language-switching task. Participants had to name pictures in Dutch or English depending on the cue. A run of same-language trials could be short (two or three trials) or long (five or six trials). We assessed whether RTs and N2 changed over the course of same-language runs, and at a switch between languages. Results showed that speakers named pictures more quickly late as compared to early in a run of same-language trials. Moreover, they made a language switch more quickly after a long run than after a short run. In ERPs, we observed a widely distributed switch effect in the N2, which was larger after a short run than after a long run. The N2 was not modulated during a same-language run, challenging Kleinman and Gollan (2018), who maintained that inhibition accumulates over time. Our results suggests that speakers adjust the level of inhibitory control at a language switch, but not when repeatedly naming in the same language.