Abstract
The characteristics of human voluntary movements with and without visual input were examined. A man was instructed to write a circle of arbitrary size, and subsequently to write the circle of the same size with eye closed condition. As a result, the size of the she second circle written with eye closed was always smaller than that of the first circle with eye open. This phenomenon was generally seen not only in the handwriting but also in other voluntary movements using hand or foot.
We can summarize the present results on the properties of human voluntary movements as follows: The magnitude of human voluntary movements depends on the velocity of the motion at that time. A periodic time of a motion is kept constant and is not a function of the velocity or amplitude of the motion. From the above view, we assume the existence of the internal “clock” which acts to regulate his own motion.
