Contribution
Surprisal elicits pupil-linked arousal response during rapid online belief updating independently of auditory domain
* Presenting author
Abstract:
The locus coeruleus (LC) arousal system is suggested to mediate perceptual belief updating by amplifying the weight of sensory input relative to prior beliefs through the release of noradrenaline (NA) . We presented two groups of participants, one per domain, with auditory sequences presenting evidences for two distinct latent states: acceleration and deceleration in the temporal domain and clockwise and counterclockwise movement in the spatial domain. Participants were tasked with inferring and tracking latent states and reporting the last current state of the sequence in a two-alternative forced-choice design. Occasional change points (CPs) within the sequences marked changes in underlying latent state and forced belief updating. We recorded task-evoked pupil sizes via pupillometry as a proxy for LC-NA activation. A Bayesian CP model was fitted to the behavioral responses from which we extracted momentary surprisal, a precision-weighted quantification of the prediction error. In line with our preregistered hypothesis, we found surprisal to predict task-evoked pupil size on a rapid stimulus-to-stimulus level, independent of the tested domain. The results support the notion of a general modulation of auditory belief updating by the LC-NA arousal system, acting on fast timescales.