Alan Gilchrist

Alan Gilchrist

Email

alan [at] psychology.rutgers.edu

Phone

973-353-3951

Office Location

Rutgers University, Psychology Department101 Warren Street, Newark, NJ 07102Smith Hall Room 342

Research Initiatives

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.


Publications

Gilchrist, A. (2017). On the Ecological Validity of Computer Displays.

Perception

, 46, 7, 1-5.


Gilchrist, A. (2016). The Staircase Gelb Illusion. In A. Shapiro & D. Todorovic (Eds.),

The Oxford Compendium of Visual Illusions

. Oxford, United Kingdom: Oxford University Press.


Gilchrist, A. (2016). The anchoring theory of lightness. In R. Luo (Ed)

Encyclopedia of Color Science and Technology

. New York: Springer.


Gilchrist, A. (2015). A Commentary on: What visual illusions tell us about underlying neural mechanisms and observer strategies for tackling the inverse problem of achromatic perception.

Frontiers in Human Neuroscience

, 9, Article 445, August, 2015.


Gilchrist, A. (2015). Perception and the social psychology of ‘The Dress’.

Perception

, 44, 1283-1285.


Economou, E., Zdravkovic, S., & Gilchrist, A. (2015). Grouping factors and the reverse contrast illusion.

Perception

, 44, 1383-1399.


Ekroll, V, Gilchrist, A, Koenderink, J, Van Doorn, A, & Wagemans, J, (2015). Poggendorff rides again. I-

Perception

, 6, 1, 15-18.


Gilchrist, A. (2014) Response to Maniatis critique of anchoring theory.

Vision Research

, 102, 93-96.


Radonjić, A. & Gilchrist, A. (2014). Lightness perception in simple images: Testing the anchoring rules.

Journal of Vision

, 14(13)


Gilchrist, A. (2014). Theoretical approaches to lightness and perception.

Perception

, 44, 339-358.


Gilchrist, A. (2014). Johannes Kepler: the sky as a retinal image.

Perception

, 43, 1283-1285.


Gilchrist, A. (2014). A gestalt account of lightness illusions.

Perception

, 43, 881-895.


Gilchrist, A. (2014) White in shadow, black in sunlight: Gray level in pigment and perception. In B. Salvesen,

See The Light, Los Angeles: Los Angeles County Museum of Art

, 208-209.


Gilchrist, A. (2014). Perceptual organization in lightness. In J. Wagemans (Ed.),

Handbook of Perceptual Organization

, 391-412.


Radonjić, A. & Gilchrist, A. (2013). Depth effect on lightness revisited: The role of articulation, proximity and fields of illumination.

iPerception

, 4, 437-455.


Gilchrist, A. (2013). Mapping luminance onto lightness in vision and art. Proc. SPIE 8651,

Human Vision and Electronic Imaging XVIII

, 865105 (March 14, 2013).


Gilchrist, A. (2012). Grayscale Range in Pigment, Paintings and Perception. In M. DeMey (Ed.),

Vision and Material

(pp. 281-297).