Modulation of haptic length representation by means of a visual illusion and optokinetic stimulation
Poster Presentation

Alberto Gallace
Department of Experimental Psychology, Oxford University, Oxford, UK

Charles Spence
Department of Experimental Psychology, Oxford University, Oxford, UK

     Abstract ID Number: 67
     Full text: Not available
     Last modified: March 16, 2006
     Presentation date: 06/20/2006 10:00 AM in Hamilton Building, Foyer
     (View Schedule)

Abstract
Research shows that a variety of different sensory manipulations, including visual illusions, transcutaneous nerve stimulation, vestibular caloric stimulation, optokinetic stimulation, and prism adaptation can all influence people’s performance on spatial tasks such as line bisection. It has been suggested that these manipulations may act upon the “higher-order” levels of representation used to code spatial information. In the present study, we investigated whether we could crossmodally influence haptic line bisection in neurologically-normal participants by varying the visual background that participants viewed. In Experiment 1, participants haptically bisected wooden rods while looking at a variant of the Oppel-Kunt visual illusion. Haptic bisection judgments were influenced by the orientation of the visual illusion (in line with previous unimodal visual findings). In Experiment 2, haptic bisection judgments were also influenced by the presence of a leftward or rightward moving visual background. These data provide the first empirical evidence to demonstrate the crossmodal effect of the Oppel-Kundt illusion and optokinetic stimulation on haptic line bisection performance. Taken together, our results suggest that the “higher-order” levels of spatial representation upon which such perceptual judgments are made have multisensory or amodal characteristics.