EFFECT OF INFORMATIONAL LOAD, INDEX OF DIFFICULTY, DIRECTION AND PLANE ANGLES OF DISCRETE MOVES IN A COMBINED MANUAL AND DECISION TASK.

Engineers and researchers concerned with the predicton of human performance in man-machine sytems have been studying the effect of various factors like information processing, decision-making and discrete motor responses involved in a man-machine system. This paper presents the experimental study which investigated the effect of Information load (H), Index of Difficulty (ID), Direction of Movement (A) and the Plane Angle of Move (V) on performance time in a combined manual and decision task. A completely randomized 3 multiplied by 3 multiplied by 4 multiplied by 6 factorial design was used in studying the effect of H, ID, A and V on performance time for a task where subjects were subjected to informational load and were required to perform a simple psychomotor task. Ten subjects were used. H, ID and A were found to be significant variables affecting performance time whereas V was not a significant determinant. The performance time was longer for movements to the left than to the right hand side moves with best performance time being obtained from 120 degree to 140 degree range. A model to predict performance time for given levels of H, ID and A has been developed. The findings may be of great help to the task as well as machine designers involving execution of combined manual and decision tasks.