Peter Ulric Tse
I received my PhD from the Vision Sciences Lab, Department of Psychology, Harvard University. My advisers were Patrick Cavanagh and Ken Nakayama. I am now doing a post-doc in Tuebingen Germany at the Max Planck Institute for Biological Cybernetics, working with Nikos Logothetis, under a grant from the McDonnell-Pew Program in Cognitive Neuroscience.
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I grew up in NYC and Long Island. In 1984 I graduated from Dartmouth College where I did a degree in physics, mathematics, and was a senior fellow n the philosophy of quantum mechanics. After graduating I worked as a math and science teacher for elementary school children in a village in Nepal as a Peace Corps volunteer. In 1987 I studied philosophy at the University of Konstanz, Germany, and then spent about five years working in Japan, mainly at Kobe Steel. I returned to the U.S. in early 1992 to begin my studies at Harvard in Psychology and formally enrolled in the Ph.D. program in the fall of 1993.
Visual illusions can teach us about the automatic and nonconscious inferences made by the visual system as it constructs a visual percept from inherently ambiguous image input. In this section I will show a few of the perceptual illusions that I have developed.
I. Transformational Apparent Motion: Above is an example of Transformational Apparent Motion. Note that this is apparent motion because there is no real animation here. There are only two frames, A and B, toggling back and forth with zero interstimulus interval. Traditional examples of apparent motion involved displacement of figures that did not change shape or overlap one another. In Transformational Apparent Motion figures overlap one another in both space and time and typically undergo a change in shape. The visual system is therefore posed with a parsing problem. Before a match can be made between figures in frames A and B, a parsing process must determine what counts as a figure. One part of my doctoral research has involved determining the geometrical constraints that govern this parsing process. The motion that you perceive here reflects your visual system's solution to the parsing problem. For more about the perception of motion, see George Mather's Motion Perception Page.
II. Wakes and Spokes: Here are motion-induced brightness illusions that I discovered called "wakes" and "spokes." Alex Holcombe has put up a nice demonstration of wakes on his website.
III. Illusory and reversible volumes: In the paper "Illusory volumes from conformation" (1998) I describe bottom-up and top-down cues and assumptions that the visual system uses to generate a volume percept from 2-D image cues. Volumes can be thought of as surfaces plus the space that they enclose. I argue that a volumetric representation is a fundamental format of mid-level vision attained before matches to memory (i.e. object recognition) or motor behaviors such as grasping. Below are some examples I have drawn of illusory and reversible volumes.
I will be adding more of my work on visual illusions in the future.
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