Pinna, BaingioGrossberg, Stephen2011-11-142011-11-142005-01https://hdl.handle.net/2144/2372Coloration and figural properties of neon color spreading and the watercolor illusion are studied using phenomenal and psychophysical observations. Coloration properties of both effects can be reduced to a common limiting condition, a nearby color transition called the "two-dots limiting case", that clarifies their perceptual similarities and dissimilarities. The results are explained by the FACADE neural model of biological vision. The model proposes how local properties of color transitions activate spatial competition among nearby perceptual boundaries, with boundaries of lower contrast edges weakened by competition more than boundaries of higher contrast edges. This asymmetry induces spreading of more color across these boundaries than conversely. The model also predicts how depth and figure-ground effects are generated in these illusions.en-USCopyright 2005 Boston University. Permission to copy without fee all or part of this material is granted provided that: 1. The copies are not made or distributed for direct commercial advantage; 2. the report title, author, document number, and release date appear, and notice is given that copying is by permission of BOSTON UNIVERSITY TRUSTEES. To copy otherwise, or to republish, requires a fee and / or special permission.Neon color spreadingWatercolor illusionAssimilationSurface colorFilling-inFigure-ground separationVisual cortexFACADE modelTechnical ReportBoston University Trustees