Acceptance of these criteria particularly favours minimal/slight deuteranomalous trichromats
that would have failed the lantern test and been rejected.
For example, if a "stringent" anomalous trichromat
apprentices under a normal-sighted stain examiner, he will learn from him to permit stains that to his stringent vision seem to incline towards red.
The metameric equivalent classes of a trichromat
require three degrees of freedom - of a tetrachromat, four degrees.
These people are dichromats as opposed to normal trichromats
All people with colour deficiencies see fewer separate hues in the environment and confuse colours that are easily distinguished by normal trichromats
(see Table 2).
Filters that change a daltonian's performance on a particular test or task, from that typical without a filter to that of a normal trichromat
, have been determined theoretically and some have been tested.
Birch (17) reported that when classification was made only when the anomalous trichromat
reported seeing a single digit, 47% of protanomalous trichromats
and 57% of deuteranomalous trichromats
were classified correctly.
A deuteranomalous trichromat
has two cone types with a photopigment spectral sensitivity peak around 560 nm (Figure 11a).
R] values over one indicate that the dichromat (real or simulated) sees the stimulus lighter than do normal trichromats
The researchers found that the more social trichromats
are, the more red coloring they show.
Coren:105) When confronted with a visible color spectrum, trichromats
can typically identify 7 or 8 distinct color bands, while dichromats will identify only 5 or 6, but tetrachromats will identify around 10.
For the response times, assumption of normality was assessed by the Shapiro-Wilk test for each of the nine participant subgroups (four additional subgroups were created by placing anomalous trichromats
in severity categories) and found to hold for all signals.
Pietroski could, of course, switch to saying that kimus have an entire system of colour vision, similar to that of normal human trichromats
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.