Range Effects in Psychophysical Scaling and a Revision of Stevens' Law

When the range of stimulus intensities varies among perceptual continua, the judgmental range tends to be invariant whether the response continuum is number, force of handgrip, or sound-pressure level. These findings are related to the view that widely varying dynamic ranges are subjectively equal. Variation in stimulus range within a continuum is also inversely related to size of exponent, but does not reflect judgmental invariance. The intramodel effect is described by a revision of Stevens' law that specifies stimulus and response ratios as the key variables.