Perceptual distortion contributes to the curvature of human reaching movements

Unconstrained point-to-point human arm movements are generally gently curved, a fact which has been used to assess the validity of models of trajectory formation. In this study we examined the relationship between curvature perception and movement curvature for planar sagittal and transverse arm movements. We found a significant correlation (P<0.0001, n=16) between the curvature perceived as straight and the curvature of actual arm movements. We suggest that subjects try to make straight-line movements, but that actual movements are curved because visual perceptual distortion makes the movements appear to be straighter than they really are. We conclude that perceptual distortion of curvature contributes to the curvature seen in human point-to-point arm movements and that this must be taken into account in the assessment of models of trajectory formation.

[1]  N. A. Bernshteĭn The co-ordination and regulation of movements , 1967 .

[2]  Arthur E. Bryson,et al.  Applied Optimal Control , 1969 .

[3]  J. M. Foley Binocular distance perception. , 1980, Psychological review.

[4]  E. Bizzi,et al.  Human arm trajectory formation. , 1982, Brain : a journal of neurology.

[5]  N. Hogan An organizing principle for a class of voluntary movements , 1984, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[6]  T. Flash,et al.  The coordination of arm movements: an experimentally confirmed mathematical model , 1985, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[7]  C. Atkeson,et al.  Kinematic features of unrestrained vertical arm movements , 1985, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[8]  Daniel Bullock,et al.  Neural dynamics of planned arm movements: emergent invariants and speed-accuracy properties during trajectory formation , 1988 .

[9]  Stephen Grossberg,et al.  Neuromuscular realization of planned arm movement trajectories , 1988, Neural Networks.

[10]  宇野 洋二,et al.  Formation and control of optimal trajectory in human multijoint arm movement : minimum torque-change model , 1988 .

[11]  S. Grossberg,et al.  Neural dynamics of planned arm movements: emergent invariants and speed-accuracy properties during trajectory formation. , 1988, Psychological review.

[12]  Eric R. Ziegel,et al.  An Introduction to Generalized Linear Models , 2002, Technometrics.

[13]  P. Morasso Spatial control of arm movements , 2004, Experimental Brain Research.

[14]  T. Flash,et al.  The control of hand equilibrium trajectories in multi-joint arm movements , 1987, Biological Cybernetics.

[15]  Michael I. Jordan,et al.  Are arm trajectories planned in kinematic or dynamic coordinates? An adaptation study , 1995, Experimental Brain Research.