AUTHOR=Preuschoff Kerstin , ’t Hart Bernard M., Einhauser Wolfgang TITLE=Pupil Dilation Signals Surprise: Evidence for Noradrenaline’s Role in Decision Making JOURNAL=Frontiers in Neuroscience VOLUME=5 YEAR=2011 URL=https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2011.00115 DOI=10.3389/fnins.2011.00115 ISSN=1662-453X ABSTRACT=
Our decisions are guided by the rewards we expect. These expectations are often based on incomplete knowledge and are thus subject to uncertainty. While the neurophysiology of expected rewards is well understood, less is known about the physiology of uncertainty. We hypothesize that uncertainty, or more specifically errors in judging uncertainty, are reflected in pupil dilation, a marker that has frequently been associated with decision making, but so far has remained largely elusive to quantitative models. To test this hypothesis, we measure pupil dilation while observers perform an auditory gambling task. This task dissociates two key decision variables – uncertainty and reward – and their errors from each other and from the act of the decision itself. We first demonstrate that the pupil does not signal expected reward or uncertainty