As a sidenote, I'd dispute that the eye is only a "sensor" for tristimulus information, if only because some women are quadrichromats (and there are rods, and there is a substantial amount of compression and therefore processing going on, and and ...)
Edmund
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Quick reference to the [a href=\"http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=303800]OMIM[/url] web site will show that human color vision is quite complex. A pertinent quote is, "...distinguished 2 types of normal color vision according to 'greenpoint,' i.e., the point at which the subject sees pure green, and 2 types according to 'bluepoint.' He presented the following genetic hypothesis: males can be of either G1/B1, G1/B2, or G2/B2; females can be of 6 genotypes."
From a brief reading of the description of the female tetrachromats, it would appear that rather than having an entirely new photo pigment, they merely may have two slightly different copies of the gene for the green pigment. One could debate is this is true tetrachromaticity.
Since the green gene is on the X-chromosome, us males can have only one copy of each gene, but there are differences among "normal" males in their green photo pigments, and all men may not see this color in quite the same way. Of course, color blind males see color quite differently. Some women could have more than 4 and up to 6 different photo pigments.
Any generalization concerning human psychology and physiology is likely to be a simplification, but many times a useful simplification for our comprehension of the processes. This leads to a veritable goldmine for nit-pickers . However, current color theory is based on the tri-stimulus theory and the camera makers have not yet accommodated these female tetrachromats, and I do not think that these advances have been incorporated into the standard CIE observer database.
Hopefully, the authority of this reference will satisfy even Papa V2.0.