Visual Processing of Depth and Color Using the McCollough Paradigm

This thesis is being archived as a Digitized Shelf Copy for campus access to current students and staff only. We currently cannot provide this open access without the author's permission. If you are the author of this work and desire to provide it open access or wish access removed please contact the Wahlstrom Library to discuss permission.Color aftereffects which depend upon the grid orientation of three dimensional colored inspection figures and of the conflicting grid orientations of a three dimensional black and white test figure may be obtained as long as the grid orientation on the test figure is not congruent. This is typical of the McCollough Effect (1965) and is seen in spite of the fact that the conflicting depths on the test figure are observed at all times. An aftereffect of color which depends solely upon the depth of three dimensional test fields may be obtained by presenting the same inspection figures, a concave vertical grating of one color in alternating sequence with a convex horizontal grating of a complementary color. This aftereffect is visible on a vertical black and white grating that is twisted to be both convex and concave. These color aftereffects follow each depth of the test figure and not the constant vertical orientation of the test grid as would be expected if color were processed by edge perceptors alone. That is, the red aftereffect of the green horizontally stripped convex figure appears on the convex section of the test figure in spite of the vertical test grid, This would suggest that color is processed both by orientation (or edge perceptors) and by depth, but not by both at the same time