Abstract des Autors

If you look back at your footprints on a snowy road, you will notice that you never move in the same way. Learning theory (Hebb, 1949) can explain the decrease of variability in human movement, but cannot explain the nature of the variability. Feedfoward motor control by the cerebellum (Shidara et al., 1993) can explain the precise movement of the limbs to objects, but cannot explain error in movement from objects. In past studies (e.g., Schoener et al., 1986; Kelso et al., 1987; Kay, 1988), the cause of errors was assumed to be noise originating in the movement system. In other words, human movement has been considered to be the result of a combination of deterministic and stochastic mechanisms. Hurst (1965) proposed an empirical law of variability for natural phenomena from observation of the rise and fall of water in rivers. Variability in stereotyped movements such as walking and running, that have been considered as repetition of the same movement, was analyzed using Hurst's empirical law. The result suggests that variation in stereotyped human movement cannot be modeled as Brownian motion or noise separated from a deterministic movement system. Verf.-Referat