Functional benefits of cognitively driven pupil‐size changes

Abstract

Pupil‐size changes are typically associated with the pupil light response (PLR), where they are driven by the physical entry of light into the eye. However, pupil‐size changes are also influenced by various cognitive processes, where they are driven by higher‐level cognition. For example, the strength of the PLR is not solely affected by physical properties of the light but also by cognitive factors, such as whether the source of light is attended or not, which results in an increase or decrease in the strength of the PLR. Surprisingly, although cognitively driven pupil‐size changes have been the focus of extensive research, their possible functions are rarely discussed. Here we consider the relative (dis)advantages of small versus large pupils in different situations from a theoretical point of view, and compare these to empirical results showing how pupil size actually changes in these situations. Based on this, we suggest that cognitively driven pupil‐size changes optimize vision either through preparation, embodied representations, or a differential emphasis on central or peripheral vision. More generally, we argue that cognitively driven pupil‐size changes are a form of sensory tuning: a subtle adjustment of the eyes to optimize vision for the current situation and the immediate future.This article is categorized under: Neuroscience > Cognition Neuroscience > Physiology Neuroscience > Behavior

Pupillary manifolds: uncovering the latent geometrical structures behind phasic changes in pupil size

“…pupil constriction, is therefore largely reflexive. However, pupil dynamics that do not have a strict environmental explanation (in terms of light levels) also exist; decades of research have ascribed them to a plethora of distinct cognitive processes spanning attention, emotion, working memory load, and executive functions more generally (Banks et al, 2015;Binda & Murray, 2015a;Einhäuser, 2017;Laeng et al, 2012;Mathôt, 2018;Mathôt & Van der Stigchel, 2015;Sirois & Brisson, 2014;Strauch et al, 2022;Vilotijević & Mathôt, 2023). Even the most fundamental Pupillary Light Reflex (PLR) is not completely impervious to cognitive, top-down modulations (Binda & Gamlin, 2017).…”

“…However, pupil dynamics that do not have a strict environmental explanation (in terms of light levels) also exist; decades of research have ascribed them to a plethora of distinct cognitive processes spanning attention, emotion, working memory load, and executive functions more generally (3)(4)(5)(6)(7)(8)(9)(10)(11).…”

Spontaneous Fluctuations in Pupil Size Shape Retinal Responses to Visual Stimuli

“…How does this in turn affect behavioral performance on different tasks? And what are the functional benefits—if any—of changes in pupil size, including the small changes induced by arousal and other cognitive factors (Vilotijević & Mathôt, 2023)? To start answering these fundamental questions, here we aim to 1) empirically investigate how changes in pupil size affect retinal responses to visual stimuli, and 2) outline a new and testable hypothesis about the role of pupil size in the earliest stage of visual perception.…”

Illusory light drives pupil responses in primates

“…Another open question is whether this phenomenon plays an adaptative role or whether it is simply an epiphenomenon without any significant function. Recently, it has been proposed that the influence of cognitive/perceptual factors on pupil responses might reflect an anticipation mechanism of probable, upcoming, light stimulation that could guarantee efficient protection against light overexposure or simply being temporarily dazzled by light, thus suggesting the possibility that this putative predictive response represents an adaptive mechanism that optimizes vision and enhances survival in our species ( Laeng, Nabil, & Kitaoka, 2022 ; Vilotijević & Mathôt, 2024b ). In this case, natural selection has likely promoted the same mechanism in a majority of species with movable pupils.…”