Effect of an auditory static distractor on the perception of an auditory moving target
Abstract
It is known that listeners lose the ability to discriminate the direction of motion of a revolving sound (clockwise vs. counterclockwise) beyond a critical velocity ("the upper limit"), primarily due to degraded front-back discrimination. Little is known about how this ability is affected by simultaneously present distractor sounds, despite the real-life importance of tracking moving sounds in the presence of distractors. We hypothesized that the presence of a static distractor sound would impair the perception of moving target sounds and reduce the upper limit, and show that this is indeed the case. A distractor on the right was as effective as a distractor at the front in reducing the upper limit despite the importance of resolving front-back confusions. By manipulating the spectral content of both the target and distractor, we found that the upper limit was reduced if and only if the distractor spectrally overlaps with the target in the frequency range relevant for front/back discrimination; energetic masking thus explains the upper limit reduction by the distractor. We did not find any evidence for informational masking by the distractor. Our findings form the first steps towards a better understanding of the tracking of multiple sounds in the presence of distractors.