Title | ||
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A Feedback Information-Theoretic Transmission Scheme (Fitts) For Modeling Trajectory Variability In Aimed Movements |
Abstract | ||
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Trajectories in human aimed movements are inherently variable. Using the concept of positional variance profiles, such trajectories are shown to be decomposable into two phases: In a first phase, the variance of the limb position over many trajectories increases rapidly; in a second phase, it then decreases steadily. A new theoretical model, where the aiming task is seen as a Shannon-like communication problem, is developed to describe the second phase: Information is transmitted from a "source" (determined by the position at the end of the first phase) to a "destination" (the movement's end-point) over a "channel" perturbed by Gaussian noise, with the presence of a noiseless feedback link. Information-theoretic considerations show that the positional variance decreases exponentially with a rate equal to the channel capacity C. Two existing datasets for simple pointing tasks are re-analyzed and observations on real data confirm our model. The first phase has constant duration, and C is found constant across instructions and task parameters, which thus characterizes the participant's performance. Our model provides a clear understanding of the speed-accuracy tradeoff in aimed movements: Since the participant's capacity is fixed, a higher prescribed accuracy necessarily requires a longer second phase resulting in an increased overall movement time. The well-known Fitts' law is also recovered using this approach. |
Year | DOI | Venue |
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2020 | 10.1007/s00422-020-00853-7 | BIOLOGICAL CYBERNETICS |
Keywords | DocType | Volume |
Fitts’, law, Speed-accuracy tradeoff, Information theory, Feedback, Variance, Movement, Motor control | Journal | 114 |
Issue | ISSN | Citations |
6 | 0340-1200 | 2 |
PageRank | References | Authors |
0.36 | 0 | 2 |
Name | Order | Citations | PageRank |
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Julien Gori | 1 | 9 | 3.16 |
Olivier Rioul | 2 | 92 | 23.54 |