Related Experiment Video
Updated: May 25, 2026

Visualizing Visual Adaptation
Published on: April 24, 2017
The relationship between peripherally matched invariant hues and unique hues: a cone-contrast approach
Athanasios Panorgias1, Janus J Kulikowski, Neil R A Parry
1Faculty of Life Sciences, Carys Bannister Building, The University of Manchester, Manchester M13 9PT, UK. apanorgias@ucdavis.edu
Abstract:
A characteristic shift in hue and saturation occurs when colored targets are viewed peripherally compared with centrally. Four hues, one in each of the red, blue, green, and yellow regions of color space, remain unchanged when presented in the peripheral field. Apart from green, these peripherally invariant hues correspond almost exactly in color space with the unique hues. We explore this puzzling observation using asymmetric color-matching and color-naming experiments and computing cone contrasts for peripheral and central stimuli. We find that the difference between cone contrasts for the peripheral and central stimuli reaches a maximum at the chromatic axis corresponding to peripherally invariant green. We speculate that the effect is linked to a weakened signal from M-cones and probably associated with a reduced number of M-cones in peripheral retina.
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