Equal-onset contours of vibrotactile stimuli

Characteristic sensations of “surge” occur at onset of vibratory stimulation, analogous to the experience of musical “attack” in the auditory modality. Such a cutaneous sensation may have a phenomenal reality that is discriminable from the sensitivity to either of its physical determinants of time and intensity. Contours of equal-onset sensation obtained by the method of adjustment permitted the assessment of the relative contributions of these two parameters. Both rise time and intensity were found to be significant factors in the determination of contours of equal-onset sensation obtained by either time adjustment or adjustment of vibratory intensity. Equating onset by intensity adjustment was found to be more difficult than equating onset by time adjustment.