NOTE ON COLOR PREFERENCE AND COLOR VISION TEST PERFORMANCE

Summary.-The incidence of color deficient vision was investigated using the Pseudo-Isochromatic Plates on a relatively large and representative group. In the sample of 112 adults aged 20 to 80 yr. and comprised of 53% women and 12% minorities, 8% of men and 3% of women were color deficient. Over-all performance indicated no effects for sex or race. Nearly half of the plates were nondiscriminating among sex, minority/majodty, and "normal" and "defective" color vision groups. Named color preferences within the "normal" group strongly favored blues and reflected no sex differences. The major theories of color vision, Young-Helmholtz trichromatic and Hering opponent-process, could be said to be chemically- or neurally-based, respectively. Biochemical assay evidence such as Wald's (1964) isolation of three pigments and MacNichol's (1964) application tends to support the trichromatic perspective, while microelectrode evidence such as DeValois's (1966) finding of four-color coding based on opponent processes supports that theory. Carlson (1980) suggested that evidence supports both a twocolor (lateral geniculate nucleus) and a three-color (cortex) coding, and Kalat (1984) surmized that there are three lunds of cones, as proposed by Young and Helmholtz, although for all other cells in the visual system, color coding resembles Hering's opponent process. Regardless of theoretical position, color deficiencies exist in 8% of men and 1% of women (Levinthal, 1983), or a population-wide incidence of 5% (McConnell, 1986). Red (protonopia) and green (deuteranopia) appear as the most common types of color deficiencies (Bennet, 1982; Levitt, 1981; Schneider & Tarshis, 1986), with evidence (Wald, 1967) for a blue deficiency (tritanopia). Schneider and Tarshis (1986) noted that red and green stimulations may be differentially sensitive to cone composition of iodopsin, and the Pseudo-Isochromatic Plates, which present 15 stimuli in the primary red-green spectrum, are commonly used to test for color vision deficiency. This study was done to assess the incidence of color vision deficiencies in a relatively large and representative sample, the discriminability of the instrument, and named color preferences for persons of "normal" color vision.