Pupillometry and the vigilance decrement: Task‐evoked but not baseline pupil measures reflect declining performance in visual vigilance tasks

Abstract

Baseline and task-evoked pupil measures are known to reflect the activity of the nervous system's central arousal mechanisms. With the increasing availability, affordability and flexibility of video-based eye tracking hardware, these measures may one day find practical application in real-time biobehavioural monitoring systems to assess performance or fitness for duty in tasks requiring vigilant attention. But real-world vigilance tasks are predominantly visual in their nature and most research in this area has taken place in the auditory domain. Here, we explore the relationship between pupil size-both baseline and task-evoked-and behavioural performance measures in two novel vigilance tasks requiring visual target detection: (1) a traditional vigilance task involving prolonged, continuous and uninterrupted performance (n = 28) and (2) a psychomotor vigilance task (n = 25). In both tasks, behavioural performance and task-evoked pupil responses declined as time spent on task increased, corroborating previous reports in the literature of a vigilance decrement with a corresponding reduction in task-evoked pupil measures. Also in line with previous findings, baseline pupil size did not show a consistent relationship with performance measures. Our data offer novel insights into the complex interplay of brain systems involved in vigilant attention and question the validity of the assumption that baseline (prestimulus) pupil size and taskevoked (poststimulus) pupil measures reflect the tonic and phasic firing modes of the locus coeruleus.

Vigilance decrement and mind-wandering in sustained attention tasks: Two sides of the same coin?

“…However, such an increase may fade quickly over time, once the task has ended, so that it is not maintained in offline after-effects. A similar pattern has been found in pupillometry experiments ( Martin et al, 2022 ). Nonetheless, we cannot rule out that the lack of increase in alpha power with time-on-task can be partially explained by the lack of electrodes in the parietal and occipital regions.…”

Isometric handgrip exercise speeds working memory responses in younger and older adults.

“…For one, pupil size is influenced not only by the noradrenergic system but also the cholinergic and serotonergic systems (Cazettes et al, 2021; Reimer et al, 2016). In addition, recent studies in mice reported that there is substantial context-related variability in the relationship between LC spiking and pupil diameter (Megemont et al, 2022; Yang et al, 2021), and in humans, it is not yet clear how baseline pupil diameter relates to task-evoked pupil diameter (Martin et al, 2022) or to another putative marker of LC activity, the P3b event-related brain potential (LoTemplio et al, 2021).…”

Pupillometry as a Window into Young Children’s Sustained Attention

“…Previous research has consistently shown that the task-evoked pupillary response decreases over time on task ( Beatty 1982a , Beatty 1982b ; Robison and Unsworth 2019 ; Unsworth and Robison 2016 ; Unsworth and Robison 2018 ; Zhao et al 2019 ). However, time-on-task effects on the baseline pupillary response have been less consistent: in adults, although several studies have shown effects of time-on-task on the baseline pupillary response ( Kristjansson et al 2009 ; Murphy et al 2011 ; Unsworth and Robison 2016 ; van den Brink et al 2016 ), others have shown no effects ( Martin et al 2022 ; Beatty 1982b ). Further, increases and decreases in baseline pupil size changes may each be related to different types of waning attention ( Unsworth and Robison 2016 ).…”