Abstract
As Gibson (1966) observed, vision is a component of a perceptual system whose function is to provide information in support of purposeful behavior. In this project we studied the perceptual system that supports the visual perception of surface properties through manipulation. In a series of trials, we gave observers the task of inspecting computer-graphics renderings of flat glossy surfaces and determining if there are any dents in the surfaces. The surfaces were displayed on a tangible display system (Ferwerda14), consisting of an Apple iPad running custom software that rendered the surface in the plane of the screen, and allowed observers to directly interact with the surface by tilting and rotating the device. On each trial we recorded how the observer manipulated the device/surface by storing the angular readings of the device’s accelerometer. Like studies showing purposeful patterns of eye movements (Yarbus67, Ballard95), the results of our studies show purposeful patterns of manipulation that are diagnostic with respect to the task by producing images that reveal the locations of the surface dents. These studies suggest the presence of an active sensori-motor perceptual system involved in the perception of surface properties, and provide a novel method for its study using tangible display systems. We are currently developing a series of psychophysical experiments to determine the limits of the system in terms of shape and material discrimination, and to analyze how the dynamic visual patterns produced by the system are coded to provide information that supports the task (Dörscher13, Phillips15).