A novel method for the construction of verbal rating scales at the ratio scale level of measurement precision: the multidimensional-psychophysical scaling procedure (M-PSP).

The multidimensional-psychophysical scaling procedure was employed to construct verbal rating scales at the ratio scale level of measurement precision. The multidimensional individual differences scaling model (INDSCAL) demonstrated a one-dimensional solution in the group stimulus space, with the eight verbal descriptors and the eight electrical stimulus intensities interdigitated with respect to their perceived strength. A plot of these stimulus coordinates against a scale of electrical intensities in milliwatts yielded an exponential function. To construct the rating scales, the four attributes that could be discerned within the dimension-namely, perceived intensities of the electrical stimuli and the attributes of the subjective experiences evoked by the electrical stimuli: pain qualities, somatosensory qualities, and emotional qualities-were plotted as separate scales against a subjective intensity scale. Although not presented here, INDSCAL also yields a subject coordinate space that quantifies the importance or saliency to each subject of each pole, stoical or complainer, of the dimension.