title: Level and mechanisms of perceptual learning: learning first-order luminance and second-order texture objects.
abstract: Perceptual learning is an improvement in perceptual task performance reflecting plasticity in the perceptual system. Practice effects were studied in two object orientation tasks: a first order, luminance object task and a second-order, texture object task. Perceptual learning was small or absent in the first-order task, but consistently occurred for the second-order (texture) task, where it was limited to improvements in low external noise conditions, or stimulus enhancement [Dosher, B., & Lu, Z. -L. (1998). Perceptual learning reflects external noise filtering and internal noise reduction through channel reweighting. Proceedings of the National Academy of Sciences of the United States of America, 95 (23) 13988-13993; Dosher, B., & Lu, Z. -L. (1999). Mechanisms of perceptual learning. Vision Research, 39 (19) 3197-3221], analogous to attention effects in first- and second-order motion processing [Lu, Z. -L., Liu, C. Q., & Dosher, B. (2000). Attention mechanisms for multi-location first- and second-order motion perception. Vision Research, 40 (2) 173-186]. Perceptual learning affected the later, post-rectification, stages of perceptual analysis, possibly localized at V2 or above. It serves to amplify the stimulus relative to limiting internal noise for intrinsically noisy representations of second-order stimuli.
authors.affiliation: Memory, Attention, and Perception (MAP) Laboratory, Department of Cognitive Sciences, Institute of Mathematical Behavioral Sciences, University of California, Irvine, 92697-5100, USA. bdosher@uci.edu
authors.forename: Barbara Anne
authors.initials: BA
authors.lastname: Dosher
authors.forename: Zhong-Lin
authors.initials: ZL
authors.lastname: Lu
mesh_terms: D001288:Attention / Q000502:physiology; D015350:Contrast Sensitivity / Q000502:physiology; D004192:Discrimination, Psychological; D006801:Humans; D007858:Learning / Q000502:physiology*; D008960:Models, Psychological; D009473:Neuronal Plasticity / Q000502:physiology; D009949:Orientation / Q000502:physiology; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics; D012684:Sensory Thresholds / Q000502:physiology