The effect of age of acquisition on listening effort: Pupillometry and subjective measures

Abstract

Bilinguals typically perform worse on speech-perception-in-noise relative to monolinguals, and bilinguals who learned the language later typically perform worse than those who learned it earlier. This decrement in performance has largely been attributed to the fact that both bilingualism and later acquisition result in comparatively less exposure to a language than monolingualism and earlier acquisition do. Though this effect of age of acquisition has been well-documented for speech recognition accuracy, less is known about how it affects listening effort. This study quantifies listening effort using three measures (pupil dilation, subjective effort ratings, and subjective fatigue ratings) for four listening conditions (quiet, easy, moderate, and hard). We collect these measures from four groups of participants: monolinguals, simultaneous bilinguals, early sequential bilinguals, and late bilinguals. Data collection is ongoing for a target sample size of 128 (32 per group). Based on related work, we expect greater listening effort for listeners with later ages of acquisition (e.g., late bilinguals relative to simultaneous bilinguals), and for that effect to increase with worsening acoustic quality (i.e., the hard relative to the easy condition). Preliminary results (N = 56) support these hypotheses. These data provide foundational insights into the relationship between bilingualism and listening effort.