Contrast discrimination: second responses reveal the relationship between the mean and variance of visual signals.
To explain the relationship between first- and second-response accuracies in a detection experiment, Swets, Tanner, and Birdsall [Swets, J., Tanner, W. P., Jr., & Birdsall, T. G. (1961). Decision processes in perception. Psychological Review, 68, 301-340] proposed that the variance of visual signals increased with their means. However, both a low threshold and intrinsic uncertainty produce similar relationships. I measured the relationship between first- and second-response accuracies for suprathreshold contrast discrimination, which is thought to be unaffected by sensory thresholds and intrinsic uncertainty. The results are consistent with a slowly increasing variance.
Solomon
Joshua A
JA
Department of Optometry and Visual Science, City University, London EC1V 0HB, UK. J.A.Solomon@city.ac.uk
D015350:Contrast Sensitivity / Q000502:physiology*; D004192:Discrimination, Psychological / Q000502:physiology*; D006801:Humans; D010775:Photic Stimulation; D011594:Psychometrics; D011601:Psychophysics; D012684:Sensory Thresholds; D017603:Signal Detection, Psychological; D035501:Uncertainty