title: The cost of accumulating evidence in perceptual decision making.
abstract: Decision making often involves the accumulation of information over time, but acquiring information typically comes at a cost. Little is known about the cost incurred by animals and humans for acquiring additional information from sensory variables due, for instance, to attentional efforts. Through a novel integration of diffusion models and dynamic programming, we were able to estimate the cost of making additional observations per unit of time from two monkeys and six humans in a reaction time (RT) random-dot motion discrimination task. Surprisingly, we find that the cost is neither zero nor constant over time, but for the animals and humans features a brief period in which it is constant but increases thereafter. In addition, we show that our theory accurately matches the observed reaction time distributions for each stimulus condition, the time-dependent choice accuracy both conditional on stimulus strength and independent of it, and choice accuracy and mean reaction times as a function of stimulus strength. The theory also correctly predicts that urgency signals in the brain should be independent of the difficulty, or stimulus strength, at each trial.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, École Normale Supérieure, 75005 Paris, France. jdrugo@gmail.com
authors.forename: Jan
authors.initials: J
authors.lastname: Drugowitsch
authors.forename: Rubén
authors.initials: R
authors.lastname: Moreno-Bote
authors.forename: Anne K
authors.initials: AK
authors.lastname: Churchland
authors.forename: Michael N
authors.initials: MN
authors.lastname: Shadlen
authors.forename: Alexandre
authors.initials: A
authors.lastname: Pouget
mesh_terms: D000818:Animals; D002755:Choice Behavior / Q000502:physiology; D003365:Costs and Cost Analysis / Q000639:trends; D003657:Decision Making / Q000502:physiology*; D005260:Female; D000882:Haplorhini; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology*; D011897:Random Allocation; D011930:Reaction Time / Q000502:physiology*