RUI: Stimulus Characteristics Influencing Non-Cardinal Color Mechanisms

Wabash College, Crawfordsville IN

Investigators

Abstract

For over 200 years it has been known that color vision begins with the three cone types in the retina. More recently, vision scientists have determined that the retina routes the cone signals into three "cardinal color" pathways: red vs. green (RG), bluish vs. yellowish (BY), and black vs. white (BW). However, the manner in which light is turned into colored perceptions is not fully understood - in particular, how do people perceive colors beyond the six cardinal colors, the "non-cardinal" colors? To investigate this, the researchers will test how different spatial characteristics of the stimuli (e.g., size, striping, contrast) affects the ability to perceive non-cardinal colors. The results may allow vision scientists to understand more about the neural mechanisms behind color perception. In addition, this project will provide research internships for undergraduate college students, the next generation of scientists, as part of NSF's mission to promote the progress of science. This project will use visual psychophysics to test the neural mechanisms underlying our ability to perceive non-cardinal colors. Although there is ample evidence that such mechanisms exist in the isoluminant plane of color space, there is less strong evidence for the two planes with luminance input (red-green/luminance and tritan/luminance). Thus, these latter two planes are a focus of the proposed studies. Non-cardinal mechanisms will be measured by the ratio of the contrast thresholds to detect the stimuli when embedded in aligned noise (same color) versus when embedded in orthogonal noise (e.g., red/green stimuli embedded in tritan noise). Stimulus attributes such as size, contrast, and gratings vs. full-field will be manipulated. In addition, the effects of perceptual learning on these non-cardinal mechanisms will be examined. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.