title: The timescale of perceptual evidence integration can be adapted to the environment.
abstract: A key computation underlying perceptual decisions is the temporal integration of "evidence" in favor of different states of the world. Studies from psychology and neuroscience have shown that observers integrate multiple samples of noisy perceptual evidence over time toward a decision. An influential model posits perfect evidence integration (i.e., without forgetting), enabling optimal decisions based on stationary evidence. However, in real-life environments, the perceptual evidence typically changes continuously. We used a computational model to show that, under such conditions, performance can be improved by means of leaky (forgetful) integration, if the integration timescale is adapted toward the predominant signal duration. We then tested whether human observers employ such an adaptive integration process. Observers had to detect visual luminance "signals" of variable strength, duration, and onset latency, embedded within longer streams of noise. Different sessions entailed predominantly short or long signals. The rate of performance improvement as a function of signal duration indicated that observers indeed changed their integration timescale with the predominant signal duration, in accordance with the adaptive integration account. Our findings establish that leaky integration of perceptual evidence is flexible and that cognitive control mechanisms can exploit this flexibility for optimizing the decision process.
authors.affiliation: School of Psychology, Tel-Aviv University, 69978 Ramat-Aviv, Israel.
authors.forename: Ori
authors.initials: O
authors.lastname: Ossmy
authors.forename: Rani
authors.initials: R
authors.lastname: Moran
authors.forename: Thomas
authors.initials: T
authors.lastname: Pfeffer
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Tsetsos
authors.forename: Marius
authors.initials: M
authors.lastname: Usher
authors.forename: Tobias H
authors.initials: TH
authors.lastname: Donner
mesh_terms: D000328:Adult; D003657:Decision Making; D004192:Discrimination, Psychological; D005260:Female; D006801:Humans; D008297:Male; D008959:Models, Neurological; D010775:Photic Stimulation; D011930:Reaction Time; D014796:Visual Perception; D055815:Young Adult