Categorical perception and absolute pitch

Abstract

Musicians with absolute pitch made magnitude estimates of 20 tone frequencies spaced over five semitones. When averaged over several blocks of trials, the resulting psychophysical functions increased smoothly as a function of tone frequency. However, for absolute pitch subjects the individual block data revealed functions with five discrete steps, such that physically different stimuli were judged by the observers to have the same subjective magnitude. These steps had variable boundaries, so that the discrete character of the functions was obscured when averaging techniques were used. The results suggest that musicians with absolute pitch have categorical perception for tone frequency, based on their knowledge of the notes of the musical scale.