Absolute Judgments Are Relative: A Reinterpretation of Some Psychophysical Ideas

A central theoretical assumption in classical psychophysics is that people judge the intensities of stimulus elements; for example, observers directly report the loudness of a tone or the intensity of a shock. A methodological assumption in classical psychophysics is that averaged data demonstrate this theoretical view. It is shown in this article that both assumptions are wrong and that the psychophysical laws of Weber, Fechner, and Stevens are not general. Rather, psychophysical judgments are made in relation to contexts and memories, measures of which provide new information about psychophysical judgments and new understandings of channel capacity, the local–global distinction, and the source of noise in signal detection theory.