RT Journal Article SR Electronic T1 Auditory accessory stimulus boosts pupil-linked arousal and reduces choice bias JF bioRxiv FD Cold Spring Harbor Laboratory SP 2022.08.28.505585 DO 10.1101/2022.08.28.505585 A1 B.M. Bruel A1 V.G. Katopodis A1 R. de Vries A1 T.H. Donner A1 M.J. McGinley A1 J.W. de Gee YR 2022 UL http://biorxiv.org/content/early/2022/08/29/2022.08.28.505585.abstract AB Recent work indicates that pupil-linked phasic arousal signals reduce the impact of prior expectations and biases on decision formation. It has remained unclear whether phasic arousal (i) causes the bias reduction, if (ii) choosing against one’s bias causes phasic arousal, or if (iii) a third variable is driving both. Here, using an auditory accessory stimulus, we found evidence for the first scenario: on accessory stimulus vs normal trials, pupil-linked phasic arousal was robustly elevated and choice bias was reduced. With computational modeling of behavior, we established that the bias reduction was not due to a change in response caution (i.e., speed-accuracy tradeoff), but due to a change in a bias in the accumulation of evidence leading up to a choice. Thus, pupil-linked phasic arousal shapes choice behavior.Competing Interest StatementThe authors have declared no competing interest.