Alan Gilchrist

Associate Professor
Rutgers University, Psychology Department
101 Warren Street, Newark, NJ 07102
Smith Hall Room 342
Office: (973) 353-5440 x3951
Fax: (973)353-1171
Research Interests
I study visual perception, especially the perception of surface color, and especially the black-white dimension. Vision is known to be based on the image projected onto the retina, but the problem of how to assign black, white and gray values to surfaces represented in that image remains unsolved, in human vision as in computer vision. Because of variations in many factors such as the background of a surface and the lighting conditions, the perception of any one specific surface color can be associated with many patterns of local stimulation at the retina. The goal of the work is to describe the software (not the hardware, or wetware) used by the visual system to decode the retinal image. The primary method is psychophysics. Naive observers are exposed to displays specially constructed so that competing theories make opposing predictions of what observers will see. The observer reports, typically involving matches made using a color chart, are then used to evaluate theories. In my lab we have approached this problem in two ways. In earlier work, an inverse-optics approach was taken in which we attempted to determine the computations necessary to recover objective properties like surface color. More recent work has focused on the pattern of errors shown by human observers when judging surface colors. These errors are systematic, not random, and the work is based on the assumption that the pattern of errors is the signature of the software used to decode the retinal image.
Selected Publications
Gilchrist, A. (2012). Objective and Subjective Sides of Perception. In Visual Experience: Sensation, Cognition, and Constancy (S. Allred and G. Hatfield, Eds). Oxford Univerisity Press.
Allred, S. R., Radonjić, A., Gilchrist, A. L., & Brainard, D. H. (2012). Lightness perception in high dynamic range images: Local and and remote luminance effects. Journal of Vision, 12(2):7.
Zdravković S, Economou E, Gilchrist A.(2012). Grouping illumination frameworks. Journal of Experimental. Psychology: Human Perception and Performance. 38(3): 776-784.
Radonjić, A., Allred, S. R., Gilchrist, A. L., & Brainard, D. H. (2011). The dynamic range of human lightness perception. Current Biology, 21(22), 1931-1936
Radonjić A, Todorović D, Gilchrist A. (2010). Adjacency and surroundedness in the depth effect on lightness. Journal of Vision. 10(9):12.