On the generalization of accommodation to head-related transfer functions

To date, there is strong evidence indicating that humans with normal hearing can adapt to non-individual head-related transfer functions (HRTFs). However, less attention has been given to studying the generalization of this adaptation to untrained conditions. This study investigated how adaptation to one set of HRTFs can generalize to another set of HRTFs. Participants were divided into two groups and trained to localize a speech stimulus reproduced binaurally using either individual or non-individual HRTFs. Training led to an improved localization performance with the trained HRTFs for both groups of participants. Results also showed that there was no difference in the localization performance improvement between the trained and untrained HRTFs for both groups, indicating a generalization of adaptation to HRTFs. The findings did not allow to precisely determine which type of learning (procedural or perceptual) primarily contributed to the generalization, thus highlighting the potential need to expose participants to longer training protocols.