Auditory-visual fusion space in darkness
Poster Presentation

David HARTNAGEL
Sciences Cognitives - IMASSA - Université Paris 8

Alain BICHOT
Sciences Cognitives - IMASSA

Martine GODFROY
NASA-Ames Research Center

Corinne ROUMES
Sciences Cognitives - IMASSA

     Abstract ID Number: 118
     Full text: Not available
     Last modified: March 21, 2005

Abstract
As space perception implies egocentred, allocentred or even geocentred cues (Paillard, 1987), multisensory space perception requires these cues from each sensory modality. Effect of dissociation between auditory and visual egocentred reference frames on auditory-visual fusion has been investigated recently (Hartnagel et al., 2004). Datas supported that reference frame for visual-auditory space is neither visual, nor auditory, but results from cross-modal dynamic interaction. Experiments on Induced Roelofs Effect (Bridgeman et al., 1997) showed that visual localization depends on surrounding visual frame. Question arises about the relative effect of visual contextual cues (allocentred cues) on fusion perception in space. The current experiment investigates the effect of shift between egocentred auditory and visual reference frame on auditory-visual fusion in darkness. In an obscured room a broadband noise burst and a 1° spot of light, 500 ms duration, were simultaneously presented with a random spatial disparity. Participants had to judge about their unity. To ensure a spatial dissociation between the visual and the auditory referentials, subject’s head was maintained, and the gaze, under eye-tracker control, oriented either straight ahead or 20° laterally shifted. Fusion limits varied according to the position of the gaze. Even in darkness auditory-visual fusion space results from cross-modal interaction.