Abstract
Although variability is a fundamental and ubiquitous feature of movement in all biological systems, skilled performance is typically associated with a low level of variability and, implicitly, random noise. Hence, during practice performance variability undergoes changes leading to an overall reduction. However, learning manifests itself through more than just a reduction of random noise. To better understand the processes underlying acquisition and control of movements we show how the examination of variability and its changes with practice provides a suitable window to shed light on this phenomenon. We present one route into this problem that is particularly suited for tasks with redundant degrees of freedom: task performance is parsed into execution and result variables that are related by some function which provides a set of equivalent executions for a given result. Variability over repeated performances is analyzed with a view to this solution manifold. We present a method that parses the structure of variability into four conceptually motivated components and review three methods that are currently used in motor control research. Their advantages and limitations are discussed.
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Notes
- 1.
Note that other researchers have referred to these two types of variables as action or performance variables on the one level versus error or task variables on the other level.
References
Arutyunyan, G. H., Gurfinkel, V. S., & Mirskii, M. L. (1968). Investigation of aiming at a target. Biophysics, 13, 536–538.
Arutyunyan, G. H., Gurfinkel, V. S., & Mirskii, M. L. (1969). Organization of movements on execution by man of an exact postural task. Biophysics, 14, 1162–1167.
∗Bernstein, N. (1967). The coordination and regulation of movement. London: Pergamon Press.
Cohen, R., & Sternad, D. (2008). Variability in matorlearning: Relocating, channeling and Reducing Noise. Experimental Brain Research.
Craig, J. J. (1986). Introduction to robotics. Reading, MA: Addison-Wesley.
∗Cusumano, J. P., & Cesari, P. (2006). Body-goal variability mapping in an aiming task. Biological Cybernetics, 94(5), 367–379.
Davids, K., Bennett, S., & Newell, K. M. (2006). Movement system variability. Champaign, IL: Human Kinetics.
Harris, C. M., & Wolpert, D. M. (1998). Signal-dependent noise determines motor planning. Nature, 394, 780–784.
Kudo, K., Tsutsui, S., Ishikura, T., Ito, T., & Yamamoto, Y. (2000). Compensatory correlation of release parameters in a throwing task. Journal of Motor Behavior, 32(4), 337–345.
∗Latash, M. L., Scholz, J. P., Danion, F., & Schöner, G. (2002). Motor control strategies revealed in the structure of variability. Exercise and Sport Sciences Reviews, 30, 26–31.
Li´egeois, A. (1977). Automatic supervisory control of the configuration and behavior of multibody mechanisms. IEEE Transactions on Systems, Man, and Cybernetics, SMC-7(12), 868–871.
Martin, T. A., Gregor, B. E., Norris, N. A., & Thatch, W. T. (2001). Throwing accuracy in the vertical direction during prism adaptation: not simply timing of ball release. Journal of Neurophysiology, 85, 2298–2302.
∗Müller, H., Frank, T., & Sternad, D. (2007). Variability, covariation and invariance with respect to coordinate systems in motor control. Journal of Experimental Psychology: Human Perception and Performance, 33(1), 250–255.
Müller, H., & Sternad, D. (2003). A randomization method for the calculation of covariation in multiple nonlinear relations: Illustrated at the example of goal-directed movements. Biological Cybernetics, 39, 22–33.
Müller, H., & Sternad, D. (2004a). Accuracy and variability in goal-oriented movements: decomposition of gender differences in children. Journal of Human Kinetics, 12, 31–50.
∗Müller, H., & Sternad, D. (2004b). Decomposition of variability in the execution of goal-oriented tasks – Three components of skill improvement. Journal of Experimental Psychology: Human Perception and Performance, 30(1), 212–233.
Mussa-Ivaldi, F. A., & Hogan, N. (1991). Integrable solutions of kinematic redundancy via impedance control. International Journal of Robotics Research, 10(5), 481–491.
Newell, K. M., & Corcos, D. M. (1993). Variability and motor control. Champaign, IL: Human Kinetics.
Newell, K. M., Deutsch, K. M., Sosnoff, J. J., & Mayer-Kress, G. (2006). Variability in motor output as noise: A default and erroneous proposition? In K. D. Davis, S. Bennett & K. M. Newell (Eds.), Movement system variability (pp. 3–22). Champaign, IL: Human Kinetics.
Scholz, J. P., & Schöner, G. (1999). The uncontrolled manifold concept: identifying control variables for a functional task. Experimental Brain Research, 126, 289–306.
Scholz, J. P., Schöner, G., & Latash, M. L. (2000). Identifying the control structure of multijoint coordination during pistol shooting. Experimental Brain Research, 135, 382–404.
Smeets, J. B. J. (2000). The relation between movement parameters and learning. Experimental Brain Research, 132(4), 550–552.
Smeets, J. B. J., & Louw, S. (2007). The contribution of covariation to skill improvement is an ambiguous measure. Journal of Experimental Psychology: Human Perception and Performance, 33(1), 246–249.
Stimpel, E. (1933). Der Wurf. In F. Krüger & O. Klemm (Eds.), Motorik (Vol. 9, pp. 109–138). München: Beck.
Vaillancourt, D. E., & Newell, K. M. (2001). Woodworth (1899): Movement variability and theories of motor control. In M. L. Latash & V. M. Zatsiorsky (Eds.), Classics in Movement Science (pp. 409–435). Champaign, IL: Human Kinetics.
Woodworth, R. S. (1899). The accuracy of voluntary movement. Psychological Review Monograph Supplements, 3(3), 1–119.
The references marked with an asterisk (*) are specifically recommended for further introduction or background to the topic.
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Müller, H., Sternad, D. (2009). Motor Learning: Changes in the Structure of Variability in a Redundant Task. In: Sternad, D. (eds) Progress in Motor Control. Advances in Experimental Medicine and Biology, vol 629. Springer, Boston, MA. https://doi.org/10.1007/978-0-387-77064-2_23
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DOI: https://doi.org/10.1007/978-0-387-77064-2_23
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