Tanner L. Lumpkin¹, Hannah V. Hyman², Ralph G. Hale³; ¹University of North Georgia

The watercolor illusion (WCI) is a color spreading illusion induced by contrasting outer and inner boarders, resulting in the dissemination of a hue similar in appearance to the lighter border. The illusion has been shown to be a strong Gestalt cue for figure-ground (F/G) organization. The color spreading area tends to be perceived as figure. In our present study, we examined the effects of the WCI on F/G assessment for regions with non-matched luminance contrast. Participants were exposed to two matched luminance conditions with gray and white ambiguous F/G regions. Each image was divided into two parts by a vertical wavy contour. Each had no WCI, WCI left, and WCI right versions. A probe was present in either the left or right region, and participants were instructed to report whether the probed region appeared as figure. Results showed a significant interaction between the probe and WCI for both matched conditions, indicating an effect of WCI on F/G assignment. The non-matched condition consisted of contrasting luminance regions. The conditions and reporting method was the same as the other two experiments. There was a significant interaction between the probe and grey region, indicating the gray region was seen as figure more often. However, the WCI failed to bias F/G in this experiment. This study furthers our understanding of the WCI interaction with contrasting luminance regions. These results enhance our understanding of color spreading mechanisms and how they interact with luminance, contrast, and perceptual organization.