This is a difficult test for normal
trichromats and up to five errors must be allowed as a pass.
* Anomalous
trichromats show capacity to differentiate between red hues, in parallel to normal trichromats--in parallel, but not in complete congruence.
In contrast, between two kinds of
trichromats, say human and honey bee, the number of primary colours will be the same, although their respective ranges of wavelength sensitivities usually differ (p.
Similarly, the anomalous
trichromats mentioned in footnote 8 seem to make the colour discriminations we make; but, again, it is doubtful that they have the same phenomena we have.
Only 27% of anomalous
trichromats learned about their defect as a result of their difficulties.
The patient is malingering and is actually a normal
trichromatA spectral sensitive function that peaks at a longer wavelength than that of a normal
trichromat[L.sub.R] values over one indicate that the dichromat (real or simulated) sees the stimulus lighter than do normal
trichromats. The opposite is true for [L.sub.R] values under one.
TABLE 1: Color Vision Deficient Groups Extent Selection Criteria Deutan Protan Mild anomalous Pass Farnsworth lantern, pass 5 5
trichromats Farnsworth-Munsell Panel D-15 Moderate anomalous Fail Farnsworth lantern, pass 5 5
trichromats Farnsworth-Munsell Panel D-15 Strong anomalous Fail Farnsworth-Munsell Panel 5 5
trichromats D-15 (but not dichromats or extreme anomalous
trichromats (a)) Dichromats Match whole red-green range on 10 9 Nagel anomaloscope even after adaptation on Trendelenberg plate Note.
Pietroski could, of course, switch to saying that kimus have an entire system of colour vision, similar to that of normal human
trichromats. But the switch would threaten the plausibility of the claim that the proper function of R, and of the mechanism that generates it -- all that the kimus' system of colour vision has ever done for them, on the historical occasions that have led to its proliferation -- has been activation of their snorf-evading locomotory routines.(15)
Since the colour vision systems of birds and fish are in fact more evolutionarily advanced than those of mammals (and thus human beings), we may be said to stand to them as colour-deficient human beings stand to normal
trichromats.
A large number of normal
trichromats and colour deficient people must be examined to obtain accurate figures.
