Action toward sound sources enhances auditory spatial confidence: on the metacognitive consequences of reaching to sounds.

Each perceptual process is accompanied with an evaluation regarding the reliability of what we are perceiving. The close connection between confidence in perceptual judgments and planning of actions has been documented in studies investigating visual perception. Here, we extend this investigation to auditory perception by focusing on spatial hearing, in which the interpretation of auditory cues can often present uncertainties. We asked if confidence in perceived sound position changes when we interact with the sound source by planning a sound-directed motor action (reaching) vs. a verbal response (naming). We tested 30 participants in a sound localization task in which they were both asked to localize sound sources by reaching them or by naming the labels above them in a within-participants experimental design. Participants performed the task with binaural hearing and with one ear plugged to increase errors and reduce confidence. Results showed that sound localization performance did not differ between reaching and naming, and yet participants felt more confident and required less time to complete the trial when reaching to the sources compared to naming them, regardless of the listening condition. Moreover, we found that during monaural listening the coherence between performance and confidence was reduced in each trial, irrespective of response type, suggesting increased difficulties in metacognitive monitoring. These findings suggest that, even in the case of spatial hearing, motor action planning plays a role in the formulation of confidence judgments, alongside sensory inputs and decision-making processes and stress the importance of including metacognitive measurements into spatial hearing research.