INFLUENCE OF TASK DEMAND CHARACTERISTICS ON WORKLOAD AND PERFORMANCE

Two experiments are reported that examined the influence of variation in task demand on performance and workload. The first experiment consi dered how the manipulation of prior level of task demand affected subs equent workload and performance. The second experiment examined the ef fects on performance and workload of increments in the level of task d emand. Results from the first study indicated that prior level of impo sed task difficulty did affect response in a manner consistent with a scaling of workload in relation to previous task conditions. The secon d study demonstrated the primacy of absolute demand level over increme nts in that demand as influencing operator response. Overall, our resu lts indicate that workload and performance are sensitive to multiple c haracteristics of the task and not instantaneous demand level alone. T hese findings are important in explaining why association and dissocia tion occur between task demand, operator efficiency, and perceived wor kload in differing performance contexts. The importance of these findi ngs for the aviation psychologist in assessing pilot and operator work load is articulated.