TIME ON TASK EFFECT ON TRACKING PERFORMANCE UNDER HEAT-STRESS

The time on task effect on human tracking performance under three levels of ambient temperature, namely; 20, 26 and 30 degree C wet-bulb globe temperature (WBGT) and under two different work/rest ratios (2/1 and 3/1) was investigated. Statistical analysis indicated that time on task had a significant detrimental effect (p less than 0 multiplied by (times) 01) on tracking performance. As the time on task increased, tracking performance decreased. The detrimental time on task effect on the tracking performance appeared to be greater in hot environments as demonstrated by the significant effect (p less than 0 multiplied by (times) 1) of the time on task/ambient temperature interaction on tracking performance. A significant deterioration in tracking performance occurred after 25 min on task. When performing the task under hot environments, this effect was more pronounced. Ambient temperature was found to deteriorate the tracking performance. A significant deterioration in tracking performance occurred after 25 min on task. When performing the task under hot environments, this effect was more pronounced. Ambient temperature was found to deteriorate the tracking performance significantly (p less than 0 multiplied by (times) 1). By raising the ambient temperature from 20 to 26 degree C WBGT, the tracking error score was approximately doubled.