Proceedings of the Annual Meeting of the Cognitive Science Society

How does the visual system generate percepts of moving forms? H ow does this happen when the forms are emergent percepts (such as illusory contours or segregated textures) and the motion percept is apparent motion between the emergent forms? A neural model of form-motion interactions is developed to explain parametric properties of psychophysical motion data and to make predictions about the parallel cortical processing streams VI -> M X and VI ->^ V 2 -> MT. The model simulates many parametric psychophysical data arising from form-motion interactions. A key linkage between form and motion data is articulated in terms of properties of visual persistence and properties of apparent motion. The model explains how an illusory contour can move in apparent motion to another illusory contour or to a luminance-derived contour; how illusory contour persistence relates to the upper ISl threshold for apparent motion; and how upper and lower ISI thresholds for seeing apparent motion between two flashes decrease with stimulus duration and narrow with spatial separation (Korte's laws). Psychophysical data are derived from an analysis of how orientationally tuned form perception mechanisms and directionally tuned motion perception mechanisms interact to generate consistent percepts of moving forms.