Visual Perception of Shape

9 September 2021 (16:00 BST) – note unusual time

Philip J. Kellman
University of California, Los Angeles, USA

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How we perceive and represent shape involves many of the deepest issues in understanding visual perception. In this talk, I consider recent progress related to 3 of these issues. 1) Abstraction in perception and representation: I describe experiments that show the abstract nature of human shape representations and the time course of their formation. 2) The relation of human perception and deep learning: I contrast abstract shape in human perception with the most successful AI approaches through experiments suggesting that deep convolutional neural networks (DCNNs), although successful in object classification, have no access to global object shape. 3) The transition from subsymbolic to symbolic encoding in vision: I will argue that understanding abstraction in human visual shape perception, and its absence in deep learning systems, require some account of a poorly understood transition: How, in visual processing, might symbolic representations be obtained from initially subsymbolic encodings? I will present experimental and modeling results that suggest an answer in perception and representation of contour shape. Evidence suggests that we encode contour shape in terms of segments of approximately constant curvature and that these initial symbolic descriptions may be based on the outputs of neural mechanisms that extract constant curvature via sets of linked orientation-sensitive units at different turning angles and scales

About Philip J. Kellman

Philip J. Kellman is Distinguished Professor and Chair of the Cognitive Area in the Department of Psychology at UCLA and Adjunct Professor of Surgery in the UCLA David Geffen UCLA School of Medicine. Kellman is known for research in perceptual organization in vision, perceptual development, perceptual learning, adaptive learning, and applications of cognitive science to learning technology. He is the author of more than 130 research papers and two books, as well as patents in computer-based learning and air traffic control display technology. Kellman’s research has been recognized by the William Chase Memorial Award from Carnegie-Mellon University, the Boyd R. McCandless Award from the American Psychological Association, a James McKeen Cattell Award, and the Wolf Aviation Prize. He has been elected to the Society of Experimental Psychologists, and he is a Fellow of the Association for Psychological Science and The Psychonomic Society.