AUDITORY AFTER-EFFECT: STATIONARY ADAPTER CHANGES THE PERCEIVED TRAJECTORIES OF MOVING SOUNDS

Abstract

Perceived trajectories of dichotically presented sound stimuli with different spatial patterns were investigated in silence and after listening to stationary adapters. The spatial position of all stimuli was determined by the interaural level differences. The subjects indicated the perceived position of the beginning and end of the stimulus trajectory. Lateralized stationary adapters had no effect on the perceived position of the neighboring (ipsilateral) stimuli, but “pushed away” the stimuli located on the opposite side of the acoustic space. After exposure to the central adapter, the lateral points of the perceived trajectories were pushed away from the adapter, regardless of the motion direction. The motion starting points located near the central adapter shifted in the direction of the stimulus motion, but the perceived position of the central endpoints was not affected by the central adapter. The effect of stationary adapters on the perceived trajectories of moving sounds can be best explained by a three-channel model of the neural coding of auditory space.