Landmark-induced positional shifts point to a shared map for auditory and visual targets
36.3027, Sunday, 17-May, 2:45 pm - 6:45 pm, Banyan Breezeway
David Aagten-Murphy1, Martin Szinte1, Heiner Deubel1; 1Allgemeine und Experimentelle Psychologie, Ludwig-Maximilians-Universität München, Munich, Germany.
Visual objects that are present both before and after saccadic eye movements have been shown to act as landmarks for the localization of other visual stimuli across saccades. We investigated whether auditory localization would also be affected by visual landmark displacement during an eye-movement. Subjects fixated in the centre of the screen while a visual landmark, consisting of two LED lights above and below the midline, appeared in the periphery. They were then required to saccade to the center of this visual landmark, which either remained stationary or was displaced during the eye-movement. On each trial two brief visual or auditory test stimuli were presented sequentially before and after the execution of the saccade, at various locations. Subjects were instructed to compare the position of the second test stimulus relatively to the position of the first one. This allowed the localization abilities of the test stimuli to be computed for different sized landmark displacements (-3°, -1.5°, 0°, 1.5° or 3°). We found that the landmark displacement induced a proportionate shift in subject’s localization of visual test stimuli, which is consistent with previous findings. Critically however, despite the head and ears remaining stationary, also the localization of the auditory test stimuli was found to be shifted, proportionate to half the landmark displacement. This indicates that the visual landmarks used to align pre-and post-saccadic visual representations also serve to calibrate auditory events localisation across saccades. Overall, these results suggest that a common, supra-modal spatial map is utilised to maintain a stable representation of objects of both modalities.