Phasic pupillary responses reveal differential engagement of attentional control in bilingual spoken language processing

Anne L Beatty-Martínez,Paola E Dussias,Rosa E Guzzardo Tamargo

doi:10.1038/s41598-021-03008-1

Abstract

Language processing is cognitively demanding, requiring attentional resources to efficiently select and extract linguistic information as utterances unfold. Previous research has associated changes in pupil size with increased attentional effort. However, it is unknown whether the behavioral ecology of speakers may differentially affect engagement of attentional resources involved in conversation. For bilinguals, such an act potentially involves competing signals in more than one language and how this competition arises may differ across communicative contexts. We examined changes in pupil size during the comprehension of unilingual and codeswitched speech in a richly-characterized bilingual sample. In a visual-world task, participants saw pairs of objects as they heard instructions to select a target image. Instructions were either unilingual or codeswitched from one language to the other. We found that only bilinguals who use each of their languages in separate communicative contexts and who have high attention ability, show differential attention to unilingual and codeswitched speech. Bilinguals for whom codeswitching is common practice process unilingual and codeswitched speech similarly, regardless of attentional skill. Taken together, these results suggest that bilinguals recruit different language control strategies for distinct communicative purposes. The interactional context of language use critically determines attentional control engagement during language processing.

Highlights

Language processing is cognitively demanding, requiring attentional resources to efficiently select and extract linguistic information as utterances unfold
Notwithstanding, if codeswitching contexts involve a cooperative as opposed to a competitive relation between the two languages, one possibility is that differences in codeswitching experience may modulate the way bilinguals engage attentional control during language processing
We capitalized on recent theoretical frameworks positing that distinct language control attentional states are mediated by the interactional demands of the language environment

Summary

Introduction

Language processing is cognitively demanding, requiring attentional resources to efficiently select and extract linguistic information as utterances unfold. Notwithstanding, if codeswitching contexts involve a cooperative as opposed to a competitive relation between the two languages, one possibility is that differences in codeswitching experience may modulate the way bilinguals engage attentional control during language processing. Non-codeswitching bilinguals consistently showed a larger early frontal positivity to codeswitching, indicating that they can reliably detect a change in language at early stages of processing, presumably due to their proven experience at maximizing language competition This contrasts with the results from codeswitching bilinguals, who did not show such differences, suggesting that when language control is engaged cooperatively, and both languages are expected, bilinguals are able to maintain a sufficiently broad focus of attention when processing codeswitches. More recent research has corroborated these results and has found that bilinguals can shift between competitive and cooperative language control states, showing a modulation of switch effects as a function of the social context (i.e., by the co-presence of a bilingual or monolingual interlocutor[22])

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