Related Experiment Video
Updated: Sep 11, 2025

Visualizing Visual Adaptation
Published on: April 24, 2017
Two contrast phenomena inconsistent with illumination assumptions
None:
Two new visual phenomena were developed to examine the assumption that observers infer illuminance in two-dimensional images. In one, the color of an object (the gestalt "figure") alters the appearance of the surrounding field ("ground"); in the other, two modulating chessboards appear similar, even though one board modulates all squares and the other modulates half the squares. Only the half-modulating board induces a perceptual change on a test patch. The phenomena cannot be explained by the assumption that observers infer illuminance but seem consistent with a network approach in which color is mediated by a task-dependent selection of spatial scale.
Related Concept Videos
Phase Contrast and Differential Interference Contrast Microscopy
In-phase-contrast microscopes, interference between light directly passing through a cell and light refracted by cellular components is used to create high-contrast, high-resolution images without staining. It is the oldest and simplest type of microscope that creates an image by altering the wavelengths of light rays passing through the specimen. Altered wavelength paths are created using an annular stop in the condenser. The annular stop produces a hollow cone of...
Perceptual 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...
Photoreceptors and Visual Pathways
Difference from Background: Limit of Detection
The LOD indicates the presence or absence...
Color Vision
Light Acquisition

