Visual and Tactile Contributions to Self-Motion Perception
Poster Presentation

Oliver Kannape
Psychology, University College Dublin

Diarmuid Whittle
Engineering, Universtity College Dublin

Michael Gilchrist
Engineering, Universtity College Dublin

Stuart Smith
Psychology, Universtiy College Dublin

     Abstract ID Number: 62
     Full text: Not available
     Last modified: March 5, 2007
     Presentation date: 07/07/2007 10:00 AM in Quad Maclauren Hall
     (View Schedule)

Abstract
The extent that visual information normally dominates in perception of self-motion through the environment is no better illustrated than by the illusion of self-motion that can be induced by visual field motion (vection). In cases of uncertain visual stimuli however, a multimodal percept can be shifted towards and even ‘captured’ by other senses. We investigated the effects of a foot proprioceptive motion stimulus on performance on a visual motion detection task. The tactile stimulus was created using two specially constructed motion platforms; visual motion was realized using random-dot kinematograms with varying percentages of coherent motion.
2IFC data for the visual motion stimulus were fit by a Bayesian routine for psychometric functions (Kuss, Jäkel, and Wichmann 2005). A significant effect on motion detection thresholds was observed for incongruent foot-visual motion stimuli (t(4)=3.27, p=0.015 < α=0.017) corresponding to the congruency effect. Motion detection thresholds did not profit from combining congruent multimodal stimuli (t(4) = 1.06, p = 0.17).
These results indicate that multisensory facilitation is not evident for spatially separated visual and tactile stimuli as predicted by the spatial rule. More importantly, and against this rule of integration, a significant effect for increasing threshold for incongruent stimuli was seen across all subjects.