The ability of subjects to discriminate between directions of a point contact moving across the fingerpad was examined. Subjects were required to report, using an adaptive two-interval, two-alternative forced-choice procedure, whether in two sequential stimuli, the apparent direction of motion changed in a clockwise or counter-clockwise direction. The overall mean discrimination threshold across eight stimulus orientations was approximately 14°, with the lowest threshold for the point motion towards the wrist. The results indicate that the lower threshold in the distal-to-proximal direction was most likely due to increased skin tension at the tip of the nail, whereby the skin in front of a moving contact point is subjected to compression and the skin behind the point (including where it is anchored to the fingernail) is subjected to tension. Thresholds across orientations were in general more uniform and higher for horizontal and vertical orientations than those reported for vibro-tactile linear contactor arrays.
|Number of pages||7|
|Journal||IPO Annual Progress Report|
|Publication status||Published - 1993|