Evolution of Motor Control: From Reflexes and Motor Programs to the Equilibrium-Point Hypothesis

This brief review analyzes the evolution of motor control theories along two lines that emphasize active (motor programs) and reactive (reflexes) features of voluntary movements. It suggests that the only contemporary hypothesis that integrates both approaches in a fruitful way is the equilib-rium-point hypothesis. Physical, physiological, and behavioral founda-tions of the EP-hypothesis are considered as well as relations between the EP-hypothesis and the recent developments of the notion of motor syner-gies. The paper ends with a brief review of the criticisms of the EP-hy-pothesis and challenges that the hypothesis faces at this time.