Musical scales and brightness evaluations: Effects of pitch, direction, and scale mode

A common form of synesthesia and nonsynesthetic cross-modal matching involves an association of visual brightness and auditory frequency, and the form of this association was studied in nonsynesthetic observers who rated the perceived brightness of ascending and descending musical scales drawn from four modes (natural, melodic, and harmonic minor modes, and major modes [including both relative and parallel major scales]). The descending harmonic minor mode was rated as darker than the descending natural/melodic minor mode. Ascending minor and major modes were rated as brighter than descending minor and major modes. In addition, musical keys that started on a higher pitch were rated as brighter than musical keys that started on a lower pitch. No consistent differences in ratings of brightness were found between musically experienced and musically inexperienced participants. The data are consistent with previous findings and suggest that more global aspects of pitch height, pitch distance between subsequent notes, and pitch contour (i.e., the direction of pitch movement), rather than mode or key per se, influence ratings of the brightness of musical stimuli, and suggest recent use of brightness as a descriptor of or synonym solely for timbre may not be appropriate.