Evaluation by Mental Stress of Paced and Self-Paced Conditions on Simple Repetitive Tasks in Design of Optimum Working Speed
Eight working speeds, conveyor-paced and self-paced, were established for a repetitive task with considerable difficulty in eye-hand coordination. The procedure for calculating pace allowances in this type of repetitive task was experimentally studied from the two angles of physiological and psychological functions of the subjects and quantative and qualitative variations of the task. The results obtained are as follows: (1) The maximum output speed under the self-paced condition was 125% of that when the subjects performed the task at their free pace. The quantative and qualitative performance of the subjects under the self-paced condition was better than that attained under the other conditions, but the physiological and psychological functions of the subjects lowered greatly 90 minutes after the start of the task. (2) When establishing the working speed for conveyor-paced operations, the basic time value calculated by the MTM procedure was satisfactorily used to set the standard speed per cycle. The time value obtained by the WF procedure, on the other hand, was not preferred in terms of both the performance and the physiological and psychological functions of the subjects.