Related Experiment Video
Updated: Jun 16, 2026
04:43
Visualizing Visual Adaptation
Published on: April 24, 2017
Colour appearance and compensation in the near periphery
Michael A Webster1, Kimberley Halen, Andrew J Meyers
1Department of Psychology, University of Nevada, Reno, NV, USA. mwebster@unr.edu
Proceedings. Biological Sciences
|February 12, 2010
Summary
Color perception remains remarkably consistent between the fovea and near periphery, despite differences in visual system spectral sensitivity. This suggests underlying compensatory mechanisms maintain visual constancy.
Area of Science:
- Visual neuroscience
- Color perception
- Human visual system
Background:
- Spectral sensitivity of the visual system differs between the fovea and periphery.
- Macular pigment density decreases with eccentricity, impacting color vision.
Purpose of the Study:
- To investigate how color appearance changes between the fovea and the near periphery (8 degrees).
- To determine if visual system adjustments compensate for changes in spectral sensitivity.
Main Methods:
- Measurement of achromatic loci and unique/binary hue loci in the fovea and periphery.
- Modeling of previous studies on age-related lens pigment changes and peripheral color appearance.
Main Results:
- Color appearance was more similar between the fovea and periphery than predicted by spectral sensitivity changes.
- Observed similarities suggest compensatory processes beyond simple gain adjustments in cones.
- Adjustments to average stimulus alone do not fully explain the observed color constancy.
Conclusions:
- Additional neural processes likely compensate for spectral sensitivity variations to maintain color constancy in the near periphery.
- These compensatory adjustments are consistent with age-related changes in lens pigment and previous hue cancellation measurements.
Related Concept Videos
01:20Anatomy of the Eyeball
The eye is a spherical, hollow structure composed of three tissue layers. The outer layer — the fibrous tunic, comprises the sclera — a white structure — and the cornea, which is transparent. The sclera encompasses some of the ocular surface, most of which is not visible. However, the 'white of the eye' is distinctively visible in humans compared to other species. The cornea, a clear covering at the front of the eye, enables light penetration. The eye's middle layer, the vascular tunic,...
01:12Perceptual Constancy
Perceptual constancy is the ability to recognize that objects remain consistent and unchanged even when their appearance varies due to changes in sensory input. There are four main types of perceptual constancy: size constancy, shape constancy, color constancy, and brightness constancy.
Size constancy is the recognition that an object remains the same size, even when its image on the retina changes. For instance, a bus is perceived to be large enough to carry people, even if it looks tiny from...
Size constancy is the recognition that an object remains the same size, even when its image on the retina changes. For instance, a bus is perceived to be large enough to carry people, even if it looks tiny from...
01:24Color Vision
Color perception begins in the retina, the light-sensitive layer at the back of the eye. Two main theories explain how colors are seen: the trichromatic theory and the opponent-process theory. The trichromatic theory, proposed by Thomas Young in 1802 and extended by Hermann von Helmholtz in 1852, suggests that color vision is based on three types of cone receptors in the retina. These cones are sensitive to different but overlapping ranges of wavelengths corresponding to red, blue, and green.
01:16Focusing of Light in the Eye
Light rays enter the eye through the cornea, a transparent dome-shaped tissue that is the eye's outermost layer. The cornea bends or refracts, light rays traveling to the pupil. The shape of the cornea determines how much of the light is bent and whether the image will be focused correctly on the retina at the back of the eye. Once the light has passed through both refraction layers, it converges into a single focal point onto a small area. This is where photoreceptors start transforming...
01:24Vision
Vision is the result of light being detected and transduced into neural signals by the retina of the eye. This information is then further analyzed and interpreted by the brain. First, light enters the front of the eye and is focused by the cornea and lens onto the retina—a thin sheet of neural tissue lining the back of the eye. Because of refraction through the convex lens of the eye, images are projected onto the retina upside-down and reversed.
01:22Photoreceptors and Visual Pathways
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category, whereas...