Abstract
The perception of space across different sensory modalities is one of a seamless whole, despite the fact that the inputs to these modalities are processed in their own specific reference frames (e.g. retinotopic, tonotopic or somatopic). Visual orienting has been shown to influence localizing of sources of other modalities [Pavani, Hussain & Driver, 2008; Pritchett, Carnevale & Harris, 2012]. Here we ask the question whether localizing auditory stimuli is influenced by saccades in a similar manner as localizing visual stimuli. The direction of apparent motion across eye movements is systematically misperceived to occur further in direction to the eye movement [Szinte & Cavanagh, 2011]. This effect has been related to the structure of an attention map that dynamically updates visual space across eye movements based on predictions about where visual stimuli appear on the retina after a saccadic displacement. We asked subjects to indicate the tilt of an apparent vertical, auditory motion for four degrees of tilt (extreme left, medium left, medium right, extreme right). Participants had no bias in judging this tilt when instructed to maintain fixation at a peripheral location. When asked to judge the tilt across eye movements, the orientation of subjective vertical was rotated in direction of the intervening eye movement. This finding is in line with the illusory perception of a tilt of transsaccadic visual apparent motion [Szinte & Cavanagh, 2011] and as such supports the notion that orienting to and localizing of auditory sources is updated across eye movements similar to that seen for visual stimuli. As such the presented results point towards a common mechanism for the perception of space across modalities.
Meeting abstract presented at VSS 2014