Megan Zirnstein (Pennsylvania State University), Janet G. Van Hell (Pennsylvania State University, Radboud University Nijmegen), & Judith F. Kroll (Pennsylvania State University)
mkz2@psu.edu
Inhibitory control; L2 comprehension; Letter fluency; ERPs
Bilingual experience has been shown to have an impact on executive function skill across the lifespan. A majority of the research on this topic, however, focuses on the relationship between language production and performance on non-linguistic control tasks. As such, very little is known about how these reported changes in cognitive control ability might influence other aspects of language use, such as reading comprehension. By utilizing an aspect of reading comprehension that has been shown to rely on executive function skill (i.e., recovery from disconfirmed predictions), our aim was to investigate how those control processes that have been implicated as critical for bilingual language processing might support online language use.
In a series of studies, we asked participants to read sentences in the L2 while their EEG was recorded. ERPs were time-locked to target words that were highly expected or unexpected, based on prior context. Performance on a domain-general inhibitory control task significantly predicted modulation of processing costs related to having a lexical prediction disconfirmed (i.e., a reduction in the late frontal positivity for unexpected target words). This effect was found for both monolinguals and bilinguals, in the L1 and L2, and for bilinguals in different immersion contexts, suggesting that the recruitment of domain-general inhibitory control mechanisms during reading is not restricted only to native readers.
Based on this finding, a remaining question was whether this recruitment of domain-general inhibition is in any way related to the types of language-related inhibition effects typically reported for bilingual language production. Therefore, in a follow-up study, we used a blocked letter fluency task to test the degree to which a group of previously tested bilingual participants were capable of disinhibiting their more dominant, native language. In this task, participants were asked to produce words that began with particular letters (e.g., F, A, S). Previous work has shown that producing first in the L2 and then in the L1, and having to produce words beginning with the same letters across languages, is most likely to induce costs related to difficulty with dis-inhibiting the L1.
Our results indicated a strong relationship between domain-general and language-related inhibition. Bilinguals with better domain-general control tended to produce more words overall in the L1 block, suggesting better skill in dis-inhibiting the L1. In addition, cognate status of the words produced in the L1, as well as the degree of orthographic overlap between that word and its L2 translation equivalent, was also important. Overall, then, we show that bilinguals, who utilize domain-general control during L2 comprehension to greater success, are also more capable of flexibly switching languages, providing much stronger evidence for the claim that bilingual language experience has a widespread effect on executive function skill.
