Reaction time to kinesthetic stimulation resulting from sudden arm displacement.

Abstract

To evaluate the role of kinesthesis in the control of precise hand and arm movements, it was necessary to know how rapidly a human could respond to a kinesthetic stimulus. This was determined by suddenly dropping the subject''s splinted arm with attached accelerometer which was held horizontally by an electromagnet and measuring the time from the drop to the onset of a stopping movement. Although kinesthetic reaction time found using this technique was shorter than kinesthetic, auditory, or tactual reaction time using a key release technique, it was still within the range for the other conditions. It is concluded that kinesthetic reaction time is too long to permit continuous voluntary control of short duration hand and arm movements by information furnished through feedback. A dual mechanism of control is suggested, wherein the volitional processes serve the function of intermittently issuing "orders" and the nonvoluntary, lower centers execute these orders without additional voluntary guidance.