Happy new ears: Rapid adaptation to novel spectral cues in vertical sound localization

Summary: Humans can adapt to changes in the acoustic properties of the head and exploit the resulting novel spectral cues for sound source localization. However, the adaptation rate varies across studies and is not associated with the aftereffects commonly found after adaptation in other sensory domains. To investigate the adaptation’ rate and measure potential aftereffects, our participants wore new-ears to alter the spectral cues for sound localization and underwent sensorimotor training to induce rapid adaptation. Within 20 min, our sensorimotor-training induced full adaptation to the new-ears, as demonstrated by changes in various performance indexes, including the localization gain, bias, and precision. Once the new ears were removed, participants displayed systematic aftereffects, evident as drop in the precision of localization lasting only a few trials. These results highlight the short-term plasticity of human spatial hearing, which is capable to quickly adapt to spectral perturbations and inducing large, yet short lived, aftereffects.