Test of the Validity of the Judged Sensory Ratio of 1:2

Abstract

Garner found that observers judged the sensory ratio of 1:2 invalidly; however, it is possible that in Garner's experiment judgments were influenced by the different sets of variable stimuli used for the test. This paper reports an experiment designed to test the validity of the judged sensory ratio of 1:2 without using different sets of variable stimuli. Bipolar continua of brightness and darkness were used. Participants first adjusted a brightness so that it was the double of a standard brightness located between the middle and the black end of the brightness continuum and subsequently adjusted a brightness so that it was the double of this double (the quadruple of the original standard brightness), or adjusted a darkness so that it was the double of a standard darkness located between the middle and the white end of the darkness continuum and subsequently adjusted a darkness so that it was the double of this double (the quadruple of the original standard darkness). Participants reported quadruples of each standard even if such quadruples could not exist on the bipolar continuum. This confirms that participants judged the sensory ratio of 1:2 invalidly.

Illumination, Background Luminance, and Perceptual Learning in Perception of Achromatic Colors

“…4, most variation is eliminated when participants are not restricted to using the bisection method. This was probably so because bisection is not a natural procedure for visual perception, as Gage's (1934) and Masin and Tommasi's (2000) results also suggest. Either way, invariance in the perception of achromatic colors under different levels and types of illumination is supported by our results, which coincides with the results obtained by Wallach (1948).…”