title: Global gain modulation generates time-dependent urgency during perceptual choice in humans.
abstract: Decision-makers must often balance the desire to accumulate information with the costs of protracted deliberation. Optimal, reward-maximizing decision-making can require dynamic adjustment of this speed/accuracy trade-off over the course of a single decision. However, it is unclear whether humans are capable of such time-dependent adjustments. Here, we identify several signatures of time-dependency in human perceptual decision-making and highlight their possible neural source. Behavioural and model-based analyses reveal that subjects respond to deadline-induced speed pressure by lowering their criterion on accumulated perceptual evidence as the deadline approaches. In the brain, this effect is reflected in evidence-independent urgency that pushes decision-related motor preparation signals closer to a fixed threshold. Moreover, we show that global modulation of neural gain, as indexed by task-related fluctuations in pupil diameter, is a plausible biophysical mechanism for the generation of this urgency. These findings establish context-sensitive time-dependency as a critical feature of human decision-making.
authors.affiliation: Institute of Psychology and Leiden Institute for Brain and Cognition, Leiden University, 2333 AK Leiden, The Netherlands.|Department of Neurophysiology and Pathophysiology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
authors.forename: Peter R
authors.identifier: 0000-0003-1963-185X
authors.initials: PR
authors.lastname: Murphy
authors.affiliation: Institute of Psychology and Leiden Institute for Brain and Cognition, Leiden University, 2333 AK Leiden, The Netherlands.
authors.forename: Evert
authors.initials: E
authors.lastname: Boonstra
authors.affiliation: Institute of Psychology and Leiden Institute for Brain and Cognition, Leiden University, 2333 AK Leiden, The Netherlands.
authors.forename: Sander
authors.initials: S
authors.lastname: Nieuwenhuis
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D002755:Choice Behavior / Q000502:physiology*; D003657:Decision Making / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D010465:Perception; D012201:Reward; D013997:Time Factors; D055815:Young Adult