Binaural Discrimination Spaces

Abstract

Discrimination performance was obtained using 500-Hz sinusoids containing various combinations of interaural amplitude and interaural-time cues. In one condition, the observer was required to discriminate between a 500-Hz binaural stimulus with an amplitude imbalance favoring the right ear and another stimulus with a time difference favoring the right ear. Other conditions required a discrimination between stimuli differing on both interaural-amplitude and interaural-time cue dimensions simultaneously. Observers were instructed to maximize the number of correct responses, and visual feedback was provided after each observer response. Performance was evaluated in terms of a distance measure analogous to d′. Lateralization performance when interaural time and intensity cues are consonant can be predicted by simple addition of the distances obtained in the corresponding single cue conditions. However, performance when the same interaural time and intensity cues are dissonant is a more complex function of single cue conditions. The results from the various conditions are discussed in terms of binaural discrimination spaces, time-intensity trading ratios, and recent MLD results using sinusoidal maskers. [Research supported in part by the National Science Foundation and in part by the Public Health Service.]