Top-down influences on the rubber hand illusion
Poster Presentation

Knut Drewing
Institute for Psychology, Giessen University

Philip Albus
Institute for Psychology, Giessen University

Anne Kunkel
Institute for Psychology, Giessen University

     Abstract ID Number: 48
     Full text: Not available
     Last modified: March 5, 2007
     Presentation date: 07/05/2007 10:00 AM in Quad Maclauren Hall
     (View Schedule)

Abstract
When a participant’s unseen real hand and an artificial seen hand are stroked in synchrony, the participant reports a vivid illusion of feeling the tactile sensations as originating from the stroking of the artificial hand. Additionally, the felt position of the real hand is shifted towards the seen artificial hand (Botvinick, & Cohen, 1998). In two experiments we investigated top-down influences on the illusion as indicated by position shift and subjective onset time and duration of the illusion. Experiment 1 demonstrated for all three measures that the extent of the illusion systematically depends on the plausibility of the seen artificial limb (hand, distorted hand, cell phone). In experiment 2, we projected changing patterns of dots onto the artificial hand. Participants had to count backwards (stepsize 1 or 3), whenever a dot was stroked, or they just looked at the dots. Cognitive control dedicated to this secondary task systematically affected subjective measures of the illusion – but not the positional shift. Our findings emphasize the importance of top-down variables for the illusion, corroborating earlier suggestions on the relevance of the body scheme (Tsakiris & Haggard, 2005) and revealing a role for cognitive control in experiencing the illusion.

Acknowledgments: DeutscheForschungsgemeinschaft (DR730/1 1, FOR 560)