Dissociation of procedural and semantic memory in absolute-pitch processing.

We describe two memory-retrieval systems in absolute-pitch (AP) processing and propose existence of a universal internal pitch template to which subpopulations of musicians selectively gain access through the two systems. In Experiment I, AP and control musicians adjusted the frequency of a pure tone to match the pitch of a visually displayed randomly selected musical note. In Experiment II the same subjects vocally produced within 2s the pitch associated with a randomly selected musical note label. AP musicians, but not controls, were highly accurate in frequency matching. Surprisingly, both AP and non-AP groups were extremely accurate in voicing the target pitch as determined from an FFT of the recorded voiced notes (i.e., sigma=0.97, 0.90 semitones, respectively). Spectrogram analysis showed that notes voiced by non-AP musicians are accurate from onset of voicing suggesting that pitch accuracy does not result from an auditory-motor feedback loop. Findings support existence of two memory-retrieval systems for musical pitch: a semantic associative form of memory used by AP musicians, and a more widespread form of procedural memory which allows precise access to internal pitch representations through the vocal-motor system.