Colour and musical pitch

Individual reactions to musical stimuli imply the extraction of more information regarding pitch than a uni-dimensional pitch theory can accommodate} the phenomenology of Absolute Pitch (AP) suggests a rare sensitivity to qualities varying on separate dimensions of 'tone-height* and 'tone-chroma'. Introspective reports by synaesthetes indicate the coding of both pitch dimensions in terms parallel to those of simple visual sensation. In EXP/A, normal discrimination of tone-height qualities is reflected in the forced-choice equation of low notes and dark colours, high notes and bright; while in EXP/B a quality consistent with the definition of tone-chroma is evident in the systematic association by chronaesthetes of colour-brightness and the cyclic sequence of fifths that underlies musical tonality relationships. By an objective decision-time technique (EXPS/C and P), the speed of visual judgments is seen to be influenced by auditory pre-stimulation, and vice versa. Individual differences in the intersensory effects observed are dichotomised by reference to measures of neuroticism and Extraversion. A battery of tests for the identification of 'genuine AI” is presented, and further differences noted in the decision-time responses to tone-height and tone-chroma by groups of AP, non-AP, and non-musical subjects. The systematic fluctuation of colour-tore integration measures across the tonality dimension provides objective support for the tone-chroma effect isolated in EXP’/B. Further confirmation of the chroma effect is noted in a questionnaire study of 'key-brightness' ratings, and each of the pitch quality is considered in relation to the discrimination of beats arising from mistimed consonances. The possible coding of chroma in AP is discussed, and implications suggested in areas of imagery and aesthetics, intersensory integration, education, musical psychology and musicology.