Temporal binding of auditory spatial information across dynamic binaural events

Simultaneity judgments were used to measure temporal binding windows (TBW) for brief binaural events (changes in interaural time and/or level differences ITD and ILD]) and test the hypothesis that ITD and ILD contribute to perception via separate sensory dimensions subject to binding via slow (100+ ms)—presumably cortical—mechanisms as in multisensory TBW. Stimuli were continuous low-frequency noises that included two brief shifts of either type (ITD or ILD), both of which are heard as lateral position changes. TBW for judgments within a single cue dimension were narrower for ITD (mean = 444 ms) than ILD (807 ms). TBW for judgments across cue dimensions (i.e., one ITD shift and one ILD shift) were similar to within-cue ILD (778 ms). The results contradict the original hypothesis, in that cross-cue comparisons were no slower than within-cue ILD comparisons. Rather, the wide TBW values—consistent with previous estimates of multisensory TBW—suggest slow integrative processing for both types of judgments. Narrower TBW for ITD than ILD judgments suggests important cue-specific differences in the neural mechanisms or the perceptual correlates of integration across binaural-cue dimensions.