Adaptation to Non-Individualized Spatial Sound Through Audiovisual Experience

1 Department of Signal Processing and Acoustics, School of Engineering, Aalto University, Finland catarina.hiipakka@aalto.fi 2 Cluster of Excellence Hearing4All, Carl von Ossietzky University, Germany Recent Brief audiovisual experience affects subsequent auditory localization. In this study we were interested in the localization of non-individualized auralised sounds before and after exposure to audiovisual stimulation. First there was a pre-test in auditory localization. Then we presented listeners with alternating auditory and audiovisual stimuli which either: were constantly mismatched (Experiment 1); had a varying mismatch with average around a mode value (Experiment 2); or had a varying mismatch with average not around a mode value (Experiment 3). In the end of each experiment, there was a post-test in auditory localization. Results showed that the perceived auditory source position was shifted in the post-test in the direction of where the visual source was in the audiovisual trials. This shift was greater when the audiovisual mismatch was constant than when it varied. There was an improvement in localization accuracy when the mismatch was constant, but not when it varied. These results reveal that audiovisual stimulation leads to an improvement of localization accuracy with non-individualized auralisations, even when light and sound are not matching in space. However, this mismatch should be predictable, otherwise worsening of localization accuracy might occur.