Adaptation to transformed auditory localization cues in a hybrid real/virtual environment.

Abstract

The ability of humans to adapt to intermodal discrepancies is an important factor in the design of virtual environments. In the present study, azimuthal localization cues were altered (to magnify azimuthal differences near zero degrees) relative to real proprioceptive, visual, and vestibular cues. Subjects were alternately tested and trained in hybrid real/virtual environments where auditory stimuli were synthesized (using a PC, Convolvotron, and electromagnetic head tracker) to be at one of 13 discrete positions marked by real lights. Testing consisted of identifying the azimuth of virtual sound sources without relevant visual feedback or significant head motion. During training, a virtual sound from one of the positions was gated on with the light at that position, and subjects turned their heads to face the composite stimulus. Further identification experiments involving modified experimental procedures, as well as minimum-audible-angle discrimination experiments, were performed to help clarify the results. Preliminary findings on resolution, bias, and identification will be briefly overviewed. [Work supported by AFOSR, Grant 90-200.]