Frequency discrimination duration effects for Huggins pitch and narrowband noise (L).

Frequency difference limens (FDLs) were measured for Huggins pitch (HP) stimuli, consisting of a 30-Hz wide band of interaurally decorrelated noise in a diotic low-pass noise and for 30-Hz wide bands of diotic narrowband noise presented in a diotic low-pass noise background. FDLs at a 400-ms duration for the two stimulus types were equated by adjusting the level of the narrowband noise relative to the background. The effects of duration on the FDLs were then measured for center frequencies of 300, 600, and 900 Hz. Although the results were compromised by floor effects at 900 Hz, at 300 and 600 Hz, the duration effects were very similar for the HP and narrowband noise stimuli, with a large improvement in performance between 100 and 400 ms. In contrast to previous results for pure tones, the effect of duration was independent of frequency. The results suggest that: (1) Binaural and monaural pitches may be processed using a common mechanism; (2) discrimination performance for HP and low-sensation-level narrowband noise stimuli is not determined by the number of waveform periods.