The effect of sustained acceleration and noise on workload in human operators.

Biodynamic stressors such as acceleration, vibration, heat, and cold can affect pilot performance. The objective of this research was to determine the individual effect of two of these stressors, sustained acceleration or high intensity pink noise, on workload in human operators. Combined stressors were not investigated. A total of 13 workload measures, including 1 subjective, 4 performance, and 8 physiological, were recorded on subjects (N = 9) performing a dual psychomotor task in the human centrifuge. Increasing noise stress (max 100 dB-A weighted) had a significant effect on the Subjective Workload Assessment Technique or SWAT scores (p = 0.0001) and reaction times (p = 0.0189); acceleration stress (average peak, 3.75 Gz) had a significant effect on SWAT (p = 0.0001), heart rate (p = 0.0001), total eye blinks (p = 0.0184), blink duration (p = 0.0017), and the standard deviation of the EMG on the tracking forearm (p = 0.0452). Although many of the workload measures were affected by the noise or acceleration, subjects were able to maintain their performance on the primary tracking task. It is concluded that biodynamic stressors, such as noise and acceleration can adversely affect subjective operator workload without affecting objective task performance.