Pupillometry in mind wandering through the lens of allostasis

Abstract

Allostasis is a predictive-processing account describing how the brain regulates psychophysiological processes in anticipation of future demands. Within this framework, internal models generate predictions about the environment and the body, which are continuously compared with incoming sensory information. Maintaining and updating these models is therefore essential for adaptive regulation. Mind wandering (MW) is a cognitive phenomenon involving a shift – either intentional or unintentional – of attention away from the immediate task or environment towards internally oriented cognition. Although MW is often associated with reduced task performance, certain forms of internally directed thought may contribute to adaptive processes such as reflecting on past experiences, and simulating future scenarios. We propose that, in some contexts, MW may support allostatic regulation by facilitating exploratory processing and internal model updating. MW is commonly investigated using subjective measures such as self-reports and thought probes, motivating growing interest in objective physiological markers, including pupillometry. Pupil dynamics are closely linked to activity in the locus-coeruleus-noradrenergic (LC-NA) system, which has recently also been interpreted within predictive-processing frameworks. In this work, we synthesize literature on MW, allostasis, LC-NA dynamics, and pupillometry into an integrated neurophysiological account. Specifically, we propose that different forms of externally disengaged cognition may involve distinct LC-NA and pupil-dynamic profiles, and that pupillometry may provide a useful window into allostatic regulation, attentional allocation, and internal model updating during MW.