Spatial integration of audio-visual infromation in the peripheral visual field.
DaeGee KANG, Ryota MIYAUCHI, Yukio IWAYA, Yo-iti SUZUKI
Poster
Time: 2009-06-30 09:00 AM – 10:30 AM
Last modified: 2009-06-04
Abstract
Audio-visual integration has been investigated by many researchers, primarily limited to the central visual field. However, humans have a peripheral visual field in addition to the central visual field. In auditory perception, humans can localize sound sources within the full three-dimensional space. As such, we have conducted a study on audio-visual integration which extends from the central visual field to include the peripheral visual field.
The experimental task was for participants to judge the spatial coherence of auditory and visual stimuli presented simultaneously. The experiment was conducted in a dark anechoic room. The visual stimulus consisted 7 white light-emitting diodes (LED's) positioned at 7 different angles (-70°, -40°, -20°, 0°, 20°, 40°, 70°) relative to the fixed head position. The auditory stimuli were presented using an array of 37 small loudspeakers on an arc from -90° to 90° with 5° spacing. For any given test, the auditory range centered around the visual stimulus location. Judgments were made using an integer scale from 1 to 5. The lower end of the scale (1) indicated 'coincidence' of the presented auditory and visual stimulus, with the upper end of the scale (5) indicated that the spatial disparity between auditory and visual stimulus was the largest. Participants consisted of 9 males and 1 female. For visual stimulus presented at 0°, within the central visual field, results show left-right symmetry in spatial disparity between the auditory and visual stimuli, centered at 0°. Namely, the rating scale value increases symmetrically as the auditory stimulus moves further away from visual stimulus. In contrast, for visual stimulus within peripheral visual field, spatial left-right disparities between both stimuli were found to be asymmetrical. Not only was the perceived disparity on the farther side less accurate, the point of coincidence (lowest rating value) was shifted in the direction opposite from the 0° fixation point by 5°. These results suggest two types of distortion in the perception of audio-visual spatial integration in the peripheral visual field as compared to the central visual field.
The experimental task was for participants to judge the spatial coherence of auditory and visual stimuli presented simultaneously. The experiment was conducted in a dark anechoic room. The visual stimulus consisted 7 white light-emitting diodes (LED's) positioned at 7 different angles (-70°, -40°, -20°, 0°, 20°, 40°, 70°) relative to the fixed head position. The auditory stimuli were presented using an array of 37 small loudspeakers on an arc from -90° to 90° with 5° spacing. For any given test, the auditory range centered around the visual stimulus location. Judgments were made using an integer scale from 1 to 5. The lower end of the scale (1) indicated 'coincidence' of the presented auditory and visual stimulus, with the upper end of the scale (5) indicated that the spatial disparity between auditory and visual stimulus was the largest. Participants consisted of 9 males and 1 female. For visual stimulus presented at 0°, within the central visual field, results show left-right symmetry in spatial disparity between the auditory and visual stimuli, centered at 0°. Namely, the rating scale value increases symmetrically as the auditory stimulus moves further away from visual stimulus. In contrast, for visual stimulus within peripheral visual field, spatial left-right disparities between both stimuli were found to be asymmetrical. Not only was the perceived disparity on the farther side less accurate, the point of coincidence (lowest rating value) was shifted in the direction opposite from the 0° fixation point by 5°. These results suggest two types of distortion in the perception of audio-visual spatial integration in the peripheral visual field as compared to the central visual field.