Friday, February 10, 2012

Tetrachromacy

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As many as half of all women are retinal tetrachromats.[8]:p.256 The phenomenon arises when an individual receives two slightly different copies of the gene for either the medium- or long-wavelength cones, which are carried on the x-chromosome. To have two different genes, a person must have two x-chromosomes, which is why the phenomenon only occurs in women.[8] For some of these retinal tetrachromats, color discriminations are enhanced, making them functional tetrachromats.[8]
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Because perception of color stems from the varying spectral sensitivity of different types of cone cells in the retina to different parts of the spectrum, colors may be defined and quantified by the degree to which they stimulate these cells. These physical or physiologicalquantifications of color, however, do not fully explain the psychophysical perception of color appearance.


text from:
Wikipedia

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