A relation between Pseudo-Haptic perception and preceding / delayed visual image

Tomoko Yonemura, Hiroki Kawasaki, Shin Okamoto, Hideyuki Ando, Taro Maeda
Poster
Time: 2009-06-30  09:00 AM – 10:30 AM
Last modified: 2009-06-04

Abstract


Previous studies have shown that modifying visual information contributes to on-line manipulations of hand movements and that pseudo-force sensations can be induced by modifying speeds of the visual hand image (Le´cuyer, Coquillart, Kheddar, Richard & Coiffet, 2000; Puscha, Martinb & Coquillart, 2009). The Pseudo-Haptic is illusion in which participants perceive force by modifying (acceleration / deceleration) the visual feedback of their ongoing motions without any real physical haptic stimulation. This phenomenon occurs when the speed of their own hand image has been modified while they move hands. However it is not known whether the speed change of peripheral visual image can cause Pseudo-Haptic perception. Therefore, we investigate Pseudo-Haptic perception when two images of their own and a peripheral hand are shown simultaneously and either of the two hand images is preceding or delayed. The peripheral hand image moves keeping a constant distance to own hand image. In our experiments, the participants are asked to move own hand from a starting point to a goal, and to report the occurrence of Pseudo-Haptic under following 5 kinds of visual feedback with/without modifications, i.e., no change, accelerated / decelerated own/peripheral hand image. For the distance between their images, 7.7 (near condition) and 13.5 (far condition) degrees of the visual angle are used, which is decided from the range of the central visual field. As a result, we found that the peripheral hand image, which is not their hand image, can also induce the Pseudo-Haptic. Regarding to the occurrence rate, Pseudo-Haptic appeared more often in the near condition when modifying the peripheral hand image. Especially the deceleration of preceding and the acceleration of the delayed image more induced the illusion in the near condition. In the far condition, this phenomenon occurred only when a peripheral hand move closer to own one. Our findings suggest that the occurrence of Pseudo-Haptic is influenced by an object nearing own hand in the range of the central visual field. We also show that adjusting the position of the peripheral hand image can control the places where pseudo-force occurs in their arm. At the end, the integrated mechanism of visual and proprioceptive information will be discussed.

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