Change detection in complex acoustic scenes

Abstract

The notion that sensitivity to temporal regularity (TR) plays a pivotal role in auditory scene analysis (ASA) has recently garnered considerable attention. Nevertheless, evidence supporting a primary role for TR is based on experiments employing simple stimuli consisting of one, or two, concurrent sound sequences. Whether the role of TR in mediating ASA is robust to more complex listening environments is unknown. The present study investigates sensitivity to TR in the context of a change detection task, employing complex acoustic scenes comprised of up to 14 concurrent auditory objects. Sequences of sounds produced by each object were either temporally regular (REG) or irregular (RAND). Listeners had to detect occasional changes (appearances or disappearances of an object) within these “soundscapes.” Listeners' performance depended on the TR of both the changing object and the scene context (TR of other objects in the scene) such that RAND contexts were associated with slower response times and substantially reduced detection performance. Therefore, even in complex scenes, sensitivity to TR is critical to our ability to analyze and detect changes in a dynamic soundscape. Importantly, the data reveal that listeners are able to acquire the temporal patterning associated with at least 14 concurrently presented objects.