Pupil dilation signals surprise: evidence for noradrenaline’s role in decision making.

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...

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Main Authors: Kerstin ePreuschoff, Bernard Marius ’t Hart, Wolfgang eEinhauser
Format: Article
Language:English
Published: Frontiers Media S.A. 2011-09-01
Series:Frontiers in Neuroscience
Subjects:
Online Access:http://journal.frontiersin.org/Journal/10.3389/fnins.2011.00115/full
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author Kerstin ePreuschoff
Bernard Marius ’t Hart
Wolfgang eEinhauser
author_facet Kerstin ePreuschoff
Bernard Marius ’t Hart
Wolfgang eEinhauser
author_sort Kerstin ePreuschoff
collection DOAJ
description 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 per se, but instead signals surprise, that is, errors in judging uncertainty. While this general finding is independent of the precise quantification of these decision variables, we then analyze this effect with respect to a specific mathematical model of uncertainty and surprise, namely risk and risk prediction error. Using this quantification, we find that pupil dilation and risk prediction error are indeed highly correlated. Under the assumption of a tight link between noradrenaline (NA) and pupil size under constant illumination, our data may be interpreted as empirical evidence for the hypothesis that NA plays the same role for uncertainty as dopamine does for reward, namely the encoding of error signals.
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spelling doaj.art-ddad3e41a438483ea05b605119520b952022-12-21T17:31:01ZengFrontiers Media S.A.Frontiers in Neuroscience1662-453X2011-09-01510.3389/fnins.2011.0011511178Pupil dilation signals surprise: evidence for noradrenaline’s role in decision making.Kerstin ePreuschoff0Bernard Marius ’t Hart1Wolfgang eEinhauser2University of ZurichPhilipps-University MarburgPhilipps-University MarburgOur 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 per se, but instead signals surprise, that is, errors in judging uncertainty. While this general finding is independent of the precise quantification of these decision variables, we then analyze this effect with respect to a specific mathematical model of uncertainty and surprise, namely risk and risk prediction error. Using this quantification, we find that pupil dilation and risk prediction error are indeed highly correlated. Under the assumption of a tight link between noradrenaline (NA) and pupil size under constant illumination, our data may be interpreted as empirical evidence for the hypothesis that NA plays the same role for uncertainty as dopamine does for reward, namely the encoding of error signals.http://journal.frontiersin.org/Journal/10.3389/fnins.2011.00115/fullPsychophysicsPupilhumansurpriseuncertaintynoradrenaline
spellingShingle Kerstin ePreuschoff
Bernard Marius ’t Hart
Wolfgang eEinhauser
Pupil dilation signals surprise: evidence for noradrenaline’s role in decision making.
Frontiers in Neuroscience
Psychophysics
Pupil
human
surprise
uncertainty
noradrenaline
title Pupil dilation signals surprise: evidence for noradrenaline’s role in decision making.
title_full Pupil dilation signals surprise: evidence for noradrenaline’s role in decision making.
title_fullStr Pupil dilation signals surprise: evidence for noradrenaline’s role in decision making.
title_full_unstemmed Pupil dilation signals surprise: evidence for noradrenaline’s role in decision making.
title_short Pupil dilation signals surprise: evidence for noradrenaline’s role in decision making.
title_sort pupil dilation signals surprise evidence for noradrenaline s role in decision making
topic Psychophysics
Pupil
human
surprise
uncertainty
noradrenaline
url http://journal.frontiersin.org/Journal/10.3389/fnins.2011.00115/full
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AT bernardmariusthart pupildilationsignalssurpriseevidencefornoradrenalinesroleindecisionmaking
AT wolfgangeeinhauser pupildilationsignalssurpriseevidencefornoradrenalinesroleindecisionmaking