Journal of Vision - Perceptual learning of bisection stimuli under roving: Slow and largely specific, by Parkosadze, Otto, Malania, Kezeli, & Herzog

Khatuna Parkosadze	Laboratory of Vision Physiology, I. Beritashvili Institute of Physiology, Tbilisi, Georgia
Thomas U. Otto	Laboratory of Psychophysics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland
Maka Malania	Laboratory of Vision Physiology, I. Beritashvili Institute of Physiology, Tbilisi, Georgia
Archil Kezeli	Laboratory of Vision Physiology, I. Beritashvili Institute of Physiology, Tbilisi, Georgia
Michael H. Herzog	Laboratory of Psychophysics, Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Switzerland

In perceptual learning, performance often improves within a short time if only one stimulus variant is presented, such as a line bisection stimulus with one outer-line-distance. However, performance stagnates if two bisection stimuli with two outer-line-distances are presented randomly interleaved. Recently, S. G. Kuai, J. Y. Zhang, S. A. Klein, D. M. Levi, and C. Yu, (2005) proposed that learning under roving conditions is impossible in general. Contrary to this proposition, we show here that perceptual learning with bisection stimuli under roving is possible with extensive training of 18000 trials. Despite this extensive training, the improvement of performance is still largely specific. Furthermore, this improvement of performance cannot be explained by an accommodation to stimulus uncertainty caused by roving.