Congratulations to Professor Rhea Eskew, who recently received a three-year grant from the National Science Foundation’s Perception, Action and Cognition Program. This grant will support a project entitled “Understanding Higher Order Color: Beyond the Cardinal Mechanisms.”

Prof. Eskew describes the project as follows:

Color offers a unique opportunity for understanding the brain mechanisms of perception, because the very first step in color processing, the absorption of light by the cone photoreceptors in the retina,  is fully understood.  This knowledge allows the color scientist to manipulate early signals in the nervous system and measure the perceptual result, precisely and quantitatively.   Perceptual and neurophysiological experiments have conclusively shown that signals from the different light-sensitive cells (photoreceptors) in the eye are combined, approximately by addition and subtraction.  Our ability to see colors and to discriminate one color from another are the result of these sums and differences, which happen in neural processes called color mechanisms.  For about the past half-century, perceptual scientists have tried to understand the number and nature of these mechanisms: Are there few color mechanisms or many?  Do they really just add and subtract photoreceptor signals, or do they perform more complex calculations?  The current research will use computational modeling, and new experimental techniques and strategies, to answer these questions.  Several of these novel methods use noise masking: random visual flickering elements will appear over a test stimulus that is to be detected.  If the noise and test are processed through the same color mechanism(s), the noise will hinder the ability of a person to see the test color (by a process like camouflage).  If the noise and test are processed in separate mechanisms, the noise will have no effect on the ability to see the test at all.  By varying the color of the noise relative to the test, the properties of the color mechanisms can be quantitatively studied.

Humans use color vision to help recognize the objects around us, and to judge what materials objects are made of.  We may also use skin color to help identify the gender and judge the health of people we encounter.  Understanding how the brain processes color information is an important part of the more general understanding of how we perceive the world around us.  There are practical applications of this research as well: color is an important part of signaling systems and information displays, and having a quantitative model of color vision will help the designer of cockpit and automotive displays, medical information and imaging displays, and even digital television systems, to more efficiently and accurately convey information to users.