Updating spatial hearing abilities through multisensory and motor cues

Spatial hearing relies on a series of mechanisms for associating auditory cues with positions in space. When auditory cues are altered, humans, as well as other animals, can update the way they exploit auditory cues and partially compensate for their spatial hearing difficulties. In two experiments, we simulated monaural listening in hearing adults by temporarily plugging and muffing one ear, to assess the effects of active or passive training conditions. During active training, participants moved an audio-bracelet attached to their wrist, while continuously attending to the position of the sounds it produced. During passive training, participants received identical acoustic stimulation and performed exactly the same task, but the audio-bracelet was moved by the experimenter. Before and after training, we measured adaptation to monaural listening in three auditory tasks: single sound localization, minimum audible angle (MAA), spatial and temporal bisection. We also performed the tests twice in an untrained group, which completed the same auditory tasks but received no training. Results showed that participants significantly improved in single sound localization, across 3 consecutive days, but more in the active compared to the passive training group. This reveals that benefits of kinesthetic cues are additive with respect to those of paying attention to the position of sounds and/or seeing their positions when updating spatial hearing. The observed adaptation did not generalize to other auditory spatial tasks (space bisection and MAA), suggesting that partial updating of sound-space correspondences does not extend to all aspects of spatial hearing.