Detection of interaural phase shifts and level differences in portions of broadband noise

Abstract

Versions of Cramer‐Huggins pitch stimuli were generated such that a narrow band (bandwidths ranged from 1–100 Hz) of a wideband, diotic noise (low‐passed filtered at 8000 Hz) was presented dichotically with an interaural phase shift or an interaural level difference. The threshold value for detecting a phase shift or a level difference in the dichotic, narrowband portion of the broadband noise was determined as a function of the center frequency of the dichotic, narrow band of noise and as a function of the bandwidth of the dichotic, narrow band of noise. A single‐interval procedure without feedback was used to estimate three point psychometric functions relating d′ to interaural phase or d′ to interauralevel difference. A random variation in the interaural level difference of the entire noise waveform was also used to force the listeners to use pitch as the cue for detection rather than some aspect of lateral position. The data will be discussed in terms of models of binaural processing and binaural pitch. [Work supported by NINCDS.]