Perceptual Science Series
Beyond phenomenological connectedness: Functional consequences of filling-in during contour interpolation
Dr. Brian Keane
Monday, April 12, 2010, 12:00pm - 07:00pm
University of Medicine and Dentistry of New Jersey and Rutgers University
Contour interpolation is a perceptual process that builds phenomenologically salient contour representations from spatially segregated edges. Interpolation not only groups visible fragments together, it also fills-in or represents boundaries that fail to project to the eye. A recently-discovered consequence is that seemingly irrelevant information appearing near an interpolated path will affect the path interpolated. In this talk, I characterize interpolation by exploring how, why, and under what circumstances filling-in regions become influential. In the first part of the talk, I use a classification image (CI) technique to show that filling-in proceeds between fragments separated in space and time, and that filling-in itself might best be considered a spatiotemporal process. Next, I offer a novel interpretation of CIs deriving from shape discrimination paradigms, and suggest that prominent CI features correspond to previously undocumented interactions between contour forming and lightness induction mechanisms. I conclude by presenting data that show that, in at least some cases, filling-in cannot be easily altered via top-down strategy. This last finding bears on neural models of object perception, and also the debate as to whether perception is encapsulated from the effects of cognitive expectation.