Psychophysical research on velvet hand illusion

• Main Author: Chai, Cindy Jia Yin
• Other Authors: Kitada Ryo
• Format: Final Year Project
• Language: English
• Published: 2018
• Subjects: DRNTU::Social sciences::Psychology::Experimental psychology
• Online Access: http://hdl.handle.net/10356/73915
• Institution: Nanyang Technological University

Humans can feel a velvet-like smooth texture when a grid of tout wires moves between their hands. This texture illusion, known as the velvet hand illusion, may be useful for realizing tactile virtual reality, whereas the nature of this illusion is scarcely known. Here, we investigated the two constraints of the illusion: (1) if two own hands are necessary to induce the illusion and (2) whether the softness of the illusion changes depending on the texture of one hand. The participants put their left hand with their own right hand or their partner’s right hand. Their right hands were covered with soft material, hard material or nothing (bare hand). The strength of the illusion was slightly stronger when their own bare left hand was used to contact their own right hand than their partner’s right hand. The perceived softness and the strength of the illusion decreased as the harder material covered the right hand. These results indicate that (1) the factor of body ownership contribute to the velvet hand illusion and (2) the softness of the illusion can be affected by the contacted material, though the strength of the illusion can decrease by using the harder material. Thus, it is possible to apply the illusion to develop a tactile virtual reality that can change the perceived softness on one hand although the range of the material may be limited to relatively soft ones to maintain the strength of the illusion. The possible mechanisms underlying the illusion are discussed.