Effect of compliance on haptic perception of curvature.
The haptic sense of geometric properties such as the curvature of a contour is derived from somatosensory cues about the motions and forces experienced during exploratory actions. This study addressed the question of whether compliance, the relationship between force and displacement, influences haptic perception of curvature. Subjects traced a curved 30 cm long compliant contour by grasping the handle of a manipulandum and reported whether the contour curved towards or away from them. The contour at which there was equal probability of responding either way was taken to represent one that was sensed as being straight. The compliance of the contour was varied, being constant, greatest in the middle or greatest at the ends. Subjects exhibited a bias in what they sensed to be a straight edge. However, the actual handpath that was judged to be straight did not vary across the three compliance profiles. Our results rule out a hypothetical strategy in which an intended motion is planned and the actual trajectory is then inferred by sensing force feedback. Another strategy in which the force against the contour is controlled and the handpath is inferred from proprioceptive feedback is more consistent with the observations.
Song
Weilai
W
Department of Neuroscience, University of Minnesota, 6-145 Jackson Hall, 321 Church St. SE, Minneapolis, MN 55455, USA.
Flanders
Martha
M
Soechting
John F
JF
D000328:Adult; D001676:Biofeedback, Psychology; D003463:Cues; D005260:Female; D006225:Hand; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D009949:Orientation / Q000502:physiology*; D011597:Psychomotor Performance; D013028:Space Perception / Q000502:physiology*