define psychophysical
Psychophysics is the scientific study of the relationship between stimuli (specified in physical terms) and the sensations and perceptions evoked by these stimuli. The term psychophysics is used to denote both the substantive study of stimulus-response relationships and the methodologies used for this study. This is but one example of what psychophysics can provide. In the Munsell Lab we use psychophysics for a variety of different purposes. We have subjects judge the magnitude of color differences against a standard color difference in order to derive color tolerances for industrial purposes.