Minimum audible angle thresholds for broadband noise as a function of the delay between the onset of the lead and lag signals.
Minimum audible angle (MAA) thresholds were determined for six experienced subjects using a two-alternative, forced-choice adaptive paradigm. Broadband pink noise from a single generator was led to two identical speakers. The two sources were activated sequentially, each for a period of 10 ms. The subject's task was to indicate whether the second (lag) sound came from a source to the right or left of the first (lead) sound. The delay between the onset of the lead and the onset of the lag signal [interstimulus onset interval (ISOI)] was systematically varied from 1 ms (both 10-ms signals were concurrently active for 9 ms) to 200 ms. For a given ISOI, the spatial separation was varied adaptively to determine the MAA. A 450% improvement in auditory spatial resolution was evident as the ISOI increased from 1 to 150 ms. A further increase in the ISOI had no systematic effect on spatial resolution. These results indicate that there is a minimum integration period between 100-150 ms for the resolution of spatial information in the auditory modality.
Perrott
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Psychoacoustics Laboratory, California State University, Los Angeles 90032.
Pacheco
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D000161:Acoustic Stimulation; D000328:Adult; D001307:Auditory Perception; D001309:Auditory Threshold; D005260:Female; D006801:Humans; D008297:Male; D013017:Sound Localization