TY - JOUR T1 - Phasic arousal suppresses suboptimal decision biases in mice and humans JF - bioRxiv DO - 10.1101/447656 SP - 447656 AU - J. W. de Gee AU - K. Tsetsos AU - L. Schwabe AU - A.E. Urai AU - D. A. McCormick AU - M. J. McGinley AU - T. H. Donner Y1 - 2019/01/01 UR - http://biorxiv.org/content/early/2019/06/17/447656.abstract N2 - Many difficult decisions are made by accumulating ambiguous evidence over time. The brain’s arousal systems are rapidly activated during such decisions. How do these rapid (“phasic”) boosts in arousal affect the decision process? Here, we have unveiled a general principle of the function of phasic arousal: suppressing suboptimal biases in evidence accumulation. We quantified phasic arousal as rapid dilations of the pupil. Pupil dilations predicted reduced biases in a range of decision-making tasks and different species. In a challenging sound-detection task, both mice and humans were less biased under high arousal. Similar bias suppression occurred when optimal biases were neutral, conservative or liberal, when evidence was accumulated from memory, and for risk-seeking biases in decisions entailing the accumulation of numerical values. In all cases, the smaller behavioral biases were explained by specific changes in evidence accumulation. Thus, phasic arousal calibrates a key computation during decision-making. ER -