Editing Color constancy (section)

== Metamerism ==
Metamerism, the perceiving of colors within two separate scenes, can help to inform research regarding color constancy.<ref>{{cite journal |last=Kalderon |first=Mark Eli |title=Metamerism, Constancy, and Knowing Which |journal=Mind |volume=117 |issue=468 |year=2008 |pages=935–971 |jstor=20532701 |doi=10.1093/mind/fzn043|url=http://sas-space.sas.ac.uk/616/1/M_Kalderon_Metamerism.pdf }}</ref><ref>{{Cite journal|last=Gupte|first=Vilas|date=2009-12-01|title=Color Constancy, by Marc Ebner (Wiley; 2007) pp 394 {{Text|ISBN}} 978-0-470-05829-9 (HB)|journal=Coloration Technology|language=en|volume=125|issue=6|pages=366–367|doi=10.1111/j.1478-4408.2009.00219.x|issn=1478-4408}}</ref> Research suggests that when competing chromatic stimuli are presented, spatial comparisons must be completed early in the visual system.   For example, when subjects are presented stimuli in a [[Dichoptic presentation|dichoptic]] fashion, an array of colors and a void color, such as grey, and are told to focus on a specific color of the array, the void color appears different than when perceived in a binocular fashion.<ref name="ReferenceB">{{cite journal | last1 = Moutoussis | first1 = K. | last2 = Zeki | first2 = S. | year = 2000 | title = A psychophysical dissection of the brain sites involved in color-generating comparisons | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 97 | issue = 14| pages = 8069–8074 | doi=10.1073/pnas.110570897| pmid = 10859348 | pmc = 16671 | bibcode = 2000PNAS...97.8069M | doi-access = free }}</ref> This means that color judgements, as they relate to spatial comparisons, must be completed at or prior to the [[Visual cortex|V1]] monocular neurons.<ref name="ReferenceB"/><ref>{{cite journal | last1 = Hurlbert | first1 = A. C. | last2 = Bramwell | first2 = D. I. | last3 = Heywood | first3 = C. | last4 = Cowey | first4 = A. | year = 1998 | title = Discrimination of cone contrast changes as evidence for colour constancy in cerebral achromatopsia | journal = Experimental Brain Research | volume = 123 | issue = 1–2| pages = 136–144 | doi=10.1007/s002210050554| pmid = 9835402 | s2cid = 1645601 }}</ref><ref>{{cite journal | last1 = Kentridge | first1 = R. W. | last2 = Heywood | first2 = C. A. | last3 = Cowey | first3 = A. | year = 2004 | title = Chromatic edges, surfaces and constancies in cerebral achromatopsia | journal = Neuropsychologia | volume = 42 | issue = 6| pages = 821–830 | doi=10.1016/j.neuropsychologia.2003.11.002| pmid = 15037060 | s2cid = 16183218 }}</ref> If spatial comparisons occur later in the visual system such as in cortical area V4, the brain would be able to perceive both the color and void color as though they were seen in a binocular fashion.