On the binding of successive sounds: Perceiving shifts in nonperceived pitches

Laurent Demany, Christophe Ramos
2005 Journal of the Acoustical Society of America  
It is difficult to hear out individually the components of a "chord" of equal-amplitude pure tones with synchronous onsets and offsets. In the present study, this was confirmed using 300-ms random ͑inharmonic͒ chords with components at least 1/2 octave apart. Following each chord, after a variable silent delay, listeners were presented with a single pure tone which was either identical to one component of the chord or halfway in frequency between two components. These two types of sequence
more » ... es of sequence could not be reliably discriminated from each other. However, it was also found that if the single tone following the chord was instead slightly ͑e.g., 1/12 octave͒ lower or higher in frequency than one of its components, the same listeners were sensitive to this relation. They could perceive a pitch shift in the corresponding direction. Thus, it is possible to perceive a shift in a nonperceived frequency/pitch. This paradoxical phenomenon provides psychophysical evidence for the existence of automatic "frequency-shift detectors" in the human auditory system. The data reported here suggest that such detectors operate at an early stage of auditory scene analysis but can be activated by a pair of sounds separated by a few seconds.
doi:10.1121/1.1850209 pmid:15759703 fatcat:mjni3xy2afb5xc5bo5d75ryeru