Spatially dynamic binaural cues have a larger influence on auditory stream segregation than static cues

Auditory scene analysis is the process used to separate and integrate acoustic information into representations of auditory objects. Spatial cues play a critical role in this process, but questions remain regarding how these cues influence auditory stream segregation. The ABA stream segregation paradigm capitalizes on a bistable stimulus capable of eliciting perception of a single (integrated) auditory stream, or two separate (segregated) auditory streams with equal probability. Here, perceptual bistability was used to assess the effectiveness of interaural level (ILD), time (ITD), and correlation (IAC) values in promoting stream segregation when kept static versus dynamically modulated, across extended ABA sequences (100 + sec). Results showed that intermediately lateralized static binaural cues (7 dB, ILD; 225 µs, ITD) minimally affected stream segregation; in contrast, systematically modulated cues did, with perceptual hysteresis-like effects. These results show that perception of movement increases the influence of binaural cues as a stimulus feature for separating sound sources more than static cues. Comparison of binaural cue segregation boundaries and traditional discrimination thresholds showed that individuals with high sensitivity to a cue (i.e., low thresholds) were more likely to have narrower segregation boundaries, indicating common cognitive processes that support spatial stream segregation and sound localization.