Gv. Paramei, COLOR SPACE OF NORMALLY SIGHTED AND COLOR-DEFICIENT OBSERVERS RECONSTRUCTED FROM COLOR NAMING, Psychological science, 7(5), 1996, pp. 311-317
An experimental procedure based on the color-naming method introduced
by Boynton, Schafer, and Neun (1964) was used to study the color appea
rance of equiluminant spectral stimuli in observers with congenital re
d-green color deficiencies, as well as in normal trichromats. subjects
' responses (choice of one or more labels from the set red, yellow, gr
een, blue, and white) were converted to numeric scores, which were use
d to estimate subjective differences between pairs of colors. Individu
al subjects' matrices were processed by means of multidimensional scal
ing. As in the direct rating of color dissimilarities in normal trichr
omats (Sokolov & Izmailov, 1983) and color-deficient observers (Parame
i, Izmailov, & Sokolov, 1991), these indirectly obtained measures yiel
ded a color space in which three dimensions appear to be necessary and
sufficient. The dimensions are interpreted as evidence for red-green,
blue-yellow, and achromatic (saturation) subsystems. Based on the col
or-naming technique, three-dimensional spaces were reconstructed for t
he color-deficient observers. These results were compared with those o
btained by Helm (1964). It is argued that retaining more than one (blu
e-yellow) dimension in the color spaces of such observers provides add
itional information indicating preservation of residual red-green disc
rimination accompanied by finer discrimination of chroma than in norma
l trichromats. The spherical model of color discrimination developed f
or normal trichromats (Izmailov & Sokolov, 1991) is shown to be valid
for color-deficient subjects as well and may be useful as a framework
for differentiating protan and deutan types of color deficiency. color
-naming functions, which seem not to reveal a differentiation between
protans and deutans, provide results from which this differentiation c
an be extracted in reconstructed color spaces.