Dissociable Pupil and Oculomotor Markers of Attention Allocation and Distractor Suppression during Listening

Abstract

Emerging evidence suggests that ocular dynamics, pupil dilation, eye movements, and blinks can serve as markers of task engagement. In this study, we examined whether these measures dissociate different perceptual states during an auditory attention task. Participants (main and control experiments; N  = 34 and 27, both sexes) listened to tone sequences designated as “Target,” “Distractor,” and “Probe,” designed to isolate active attention from suppression of irrelevant input. We focused on four physiological signals: pupil diameter (PD), pupil dilation rate (PDR), blink rate, and microsaccades (MS). Compared with a control condition, both Target and Probe intervals elicited sustained PD increases, blink suppression, and prolonged MS inhibition consistent with heightened arousal and extended attentional engagement. The Distractor interval also showed prolonged blink suppression and elevated PDR, suggesting active arousal during the suppression of irrelevant input. Notably, however, MS dynamics during the Distractor were indistinguishable from those in the control condition, demonstrating no difference between active distractor suppression and passive listening. This dissociation supports the interpretation that the MS rate is specifically modulated by attention allocation, while PD and blinks also reflect general arousal or suppressive mechanisms. Overall, these findings reveal that PD, MS, and blinking capture distinct aspects of cognitive control. Together, they offer a multidimensional framework for studying selective attention and distractor suppression in complex tasks.