Bilinguals Differ From Monolinguals in Attentional Resource Allocation During Spoken Language Processing: Pupillometry Evidence

Abstract

Bilingual experience may enhance attentional control, but little work has addressed whether monolinguals and bilinguals differ in attentional resource allocation, especially in the auditory domain. Focusing on spoken language processing, we used pupillometry to examine listening effort in English monolinguals (n = 36) and simultaneous bilinguals (n = 34), while they listened to passages in two different conditions (familiar vs. unfamiliar language). Pupil dilation results indicated an interaction between language groups and conditions. Monolinguals showed significantly larger pupil size when listening to the unfamiliar language than the familiar one, whereas bilinguals had similar pupil dilation across conditions. We also found that more English exposure (especially a longer stay in an English-speaking family) correlated with smaller pupil size, particularly in the familiar language condition. Finally, we observed no significant relationship between participants’ pupil responses and their language and cognitive ability scores. Overall, our findings suggest that bilinguals tend to exhibit higher listening effort than monolinguals during spoken language processing. Further, a more cognitively demanding situation (i.e., listening to an unknown language) requires more effort in monolinguals. With this, we broadened the scope of research on bilingual cognition and demonstrated that bilingualism affects attentional resource allocation during spoken language processing.