title: Characterizing perceptual performance at multiple discrimination precisions in external noise.
abstract: Existing observer models developed for studies with the external noise paradigm are strictly applicable only to target detection or identification/discrimination of orthogonal target(s). We elaborated the perceptual template model (PTM) to account for contrast thresholds in identifying nonorthogonal targets. Full contrast psychometric functions were measured in an orientation identification task with four orientation differences across a wide range of external noise levels. We showed that observer performance can be modeled by the elaborated PTM with two templates that correspond to the two stimulus categories. Sampling efficiencies of the human observers were also estimated. The elaborated PTM provides a theoretical framework for characterizing joint feature and contrast sensitivity of human observers.
authors.affiliation: Laboratory of Brain Processes (LOBES), Department of Psychology, and Neuroscience Graduate Program, University of Southern California, Los Angeles, California 90089, USA.
authors.forename: Seong-Taek
authors.initials: ST
authors.lastname: Jeon
authors.forename: Zhong-Lin
authors.initials: ZL
authors.lastname: Lu
authors.forename: Barbara Anne
authors.initials: BA
authors.lastname: Dosher
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D003201:Computers; D006801:Humans; D015233:Models, Statistical; D016011:Normal Distribution; D055095:Optics and Photonics; D010465:Perception; D011601:Psychophysics; D013269:Stochastic Processes; D014785:Vision, Ocular; D014796:Visual Perception / Q000502:physiology*