HARMONIC-ANALYSIS OF A COMPLEX MOTOR BEHAVIOR

This study deals with the learning of a complex motor task, The exampl e used is rock climbing, where the subject's motricity is highly const rained by the natural environment. The working hypothesis is that the sensorimotor system searches for behavioral solutions characterized by minimal energy expenditure in the dissipation of forces, Harmonic sys tems - which satisfy this requirement - are used as models for testing the source signal defined by the acceleration curve at the learner's center of gravity, It is shown that only the dynamics of an expert's m otor behavior are harmonic, while those of a beginner are stochastic ( or chaotic). It is also shown that for experts, the process of adaptat ion to environmental constraints involves the relaxation of the dynami cs and the ensuing emergence of a stable state which corresponds to a quasi-periodic attractor. A harmonic analysis is used to distinguish t he environmental and intrinsic components of the behavioral dynamics, shown to result from the:coupling of these two components via resonanc e.