Beep, be-, or -ep: The impact of auditory transients on perceived bouncing/streaming

Establishing object correspondence over time ("Which object went where?") is important for productively interacting with the surrounding environment. Here, we study auditory contributions to this process using the ambiguous bouncing/streaming display. Typically, a brief coinciding tone alters this dynamic event toward the perception of 2 disks bouncing off each other rather than streaming past each other. In 4 experiments, we tested the hypothesis that this crossmodal interaction is primarily driven by additive contributions of sensory transients rather than by the high-level processing of sound category. We orthogonally manipulated the number and semantic category of auditory transients. Specifically, different combinations of auditory transients generate qualitatively different events with distinct meanings; a single auditory transient can be a tone onset or offset, and a pair of transients can be a brief tone (onset + offset) or a brief gap (offset + onset). The proportion of seeing bouncing was larger for 2 transients than 1 transient and larger for 1 transient than no transients regardless of the sound's semantic category. A tone onset and a tone offset were equally effective (relative to no transients), and a brief tone (onset + offset) and a brief gap (offset + onset) were equivalently more effective. We identified a critical window of ±200 ms around the visual overlap; a longer tone whose offset occurred outside the window was only as effective as a single onset. These results suggest that a simple addition of auditory transients within the critical time window primarily contributes to the auditory biasing of visual bouncing percepts. (PsycINFO Database Record (c) 2018 APA, all rights reserved).