Haptic Illusion: Apparent Elongation of a Disk Rotated between the Fingers

Science  09 Feb 1973:
Vol. 179, Issue 4073, pp. 590-592
DOI: 10.1126/science.179.4073.590


A disk (coin) turned end over end between thumb and forefinger feels longer to the turning hand. The illusion grows rapidly for 30 seconds but does not become asymptotic within 60 seconds. The illusion increases with coin size and turning rate, and is independent of holding pressure. It appears to involve illusory mechanisms in both hands.