The effects of acoustic variability on absolute pitch categorization: Evidence of contextual tuning.

Absolute pitch (AP) is defined as the ability to label a musical note without the aid of a reference note. Despite the large amounts of acoustic variability encountered in music, AP listeners generally experience perceptual constancy for different exemplars within note categories (e.g., recognizing that a C played on a tuba belongs to the same category as a C played on a piccolo). The present studies investigate whether AP possessors are sensitive to context variability along acoustic dimensions that are not inherently linked to the typical definition of a note category. In a speeded target recognition task, AP participants heard a sequence of notes and pressed a button whenever they heard a designated target note. Within a trial the sequence of notes was either blocked according to note-irrelevant variation or contained a mix of different instruments (Experiment 1), amplitude levels (Experiment 2), or octaves (Experiment 3). Compared to the blocked trials, participants were significantly slower to respond in the mixed-instrument and mixed-octave trials, but not the mixed-amplitude trials. Importantly, this performance difference could not be solely attributed to initial performance differences between instruments, amplitudes, or octaves. These results suggest that AP note identification is contextually sensitive.