Fishbone Tactile Illusionを利用した触対象の凹知覚の研究(「ハプティックインタラクション」特集)

抄録

Tactile sensation usually provides reliable perception of an object's presence and its surface geometric profile. We can easily conduct a part of daily behaviors without looking at. However, the human tactile sensation is not necessarily faithful reproduction of the physical property of an object in real world. Here we report a novel tactile illusion named as "Fishbone Tactile illusion": in which depth perception of the contact surface occurs through stroking by a fingertip even though the surface profile is physically flat. We investigated the effects of the touching modes (static and active) and that of the surface profile of stimuli (presence/non presence and width of smooth-flat contact surface) on the illusionary perception of stimulus geometry. The results from the two experiments suggest that this illusion is induced when the stimulus satisfies following at least two conditions: 1. a central smooth region is surrounded by rough adjacent regions; 2. a central smooth strip is required when the width of its region is below 1.5 mm. This phenomenon may reveal the basic of human tactile system to process the perception of depth in finger tip because of its robustness and simplicity.