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Experiments were conducted to determine the extent to which listeners can discriminate between different combinations of interaural time and intensity for binaural stimulus configurations which eliminate loudness, lateralization, and image-diffuseness cues. A two-interval forced choice paradigm was used, and the task of the subject was to determine the order of two stimuli, each of which was a slowly gated 500-Hz tone with a combination of interaural time and intensity differences that resulted in a centered primary spatial image. The two stimuli to be discriminated were symmetric in that they differed only in the polarity of their interaural differences. Also, in order to reduce artifacts introduced by variations in the coupling of the earphones to the head, acoustic monitoring and compensation was performed both before and after each experimental run. The performance of the two most highly trained subjects is consistent with previous experimental results that indicate an incomplete trading of interaural time and intensity information. The subjective perceptions of these observers are not consistent with previous studies that describe a ''time image'' and a ''time-intensity traded'' spatial image. [ABSTRACT FROM AUTHOR]

New experiments have been conducted to determine the extent to which listeners can discriminate between different combinations of interaural time and interaural amplitude for stimulus configurations which eliminate loudness, lateralization, and image-diffuseness cues. A 21, 2AFC paradigm was used and the task of the subject was to determine the order of two stimuli, each of which was a slowly gated 500-Hz tone with an interaural time and amplitude combination that resulted in a centered image. The two stimuli to be discriminated were symmetric in that they differed only in the polarity of the interaural differences. Also, in order to reduce artifacts introduced by variations in the coupling of the earphones to the head, acoustic monitoring was performed both before and after each experimental run. For three of the four subjects tested, discrimination performance was at the chance level. However, the fourth subject (the experimenter) was able to perform well above chance after extensive practice utilizing a special listening technique. His perceptions were not consistent with models predicting a 'time' image and a 'time-intensity traded' image. [Work supported by NIH.] [ABSTRACT FROM AUTHOR]