Terhardt, E. (1977). Pitch shift of monaural pure tones caused by contralateral sounds. Acustica 37, 56-57
Pitch shifts of monaural pure tones (i.e. changes in perceived pitch when a tone's frequency is constant) are described which are produced by simultaneous contralateral interfering sounds (wide-band noise, tones, and narrow-band noise). With wide band noise as interfering stimulus, pitch shifts occur only at frequencies beyond 700 Hz. With narrow-band stimuli, shifts are confined to test tones with frequencies near those of the interfering stimulus. The effect is typically produced with low SPLs of interfering stimuli. It cannot be ascribed to masking such as in the case of ipsilateral interfering stimuli. It is conluded that the observed pitch shifts are dependent on interaction of the two ears at a level of neural processing which is preceded by separate frequency selective mechanisms.