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 trichromat
A 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.