Audio-Visual Integration in 3D Space Near the Body

Previous research has investigated variations in the effectiveness of audio-visual (AV) integration dependent on location relative to the observer, with inconsistent results. Here, we examine AV interactions in the 3D space around an observer and address six factors that may contribute to these inconsistencies. Using a redundant-targets-effect paradigm in virtual reality, we conducted speeded detection and localization tasks to randomly intermixed auditory, visual and audio-visual stimuli presented in near or far, left or right regions of space around an observer. We varied stimulus characteristics to control for distance-related magnitude variations, examined static and looming stimuli, and analysed response times, multisensory benefits, and race model violations across conditions. Our findings reveal location-related effects on AV integration for looming but not stationary stimuli. Specifically, we observed near-space enhancement for AV looming stimuli for participants' sensory-motor responses and a left/near space enhancement for the multisensory benefit. Our method of intermixing stimulus locations and magnitude adjustments to control for inverse effectiveness was critical for demonstrating these effects. Task goals modified outcomes in complex ways. These results provide new insights into AV integration in 3D space, extend previous findings and highlight the importance and limitations of methodological factors.