Effect of informational load on human performance in a combined manual and decision task

With the increased automation, the worker's role in the industry is changing. He is required to make use of his decision making as well as motor capabilities (Type II tasks). Production system designers and managers are required to predict and evaluate human performance. The techniques available are suitable for tasks involving manual motions. To obtain an insight of the human performance characteristics for Type II tasks, experimental investigations in which the informational load could be varied and the magnitude of manual motions could also be altered were undertaken. Five subjects were tested in a 3 x 2 completely randomized and full factorial experiment. The three levels of informational load were 1, 2 and 3 bits and two distances of manual motions were 7 inches and 14 inches. In addition to measuring performance times, heart rate and breathing rate of the subjects were also monitored. Performance time and heart rate difference were observed to increase as the informational load increased, while the distance was kept invariant. Breathing rate was not found to be a significant variable.