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).