1Measures and Models for Estimating and Predicting Cognitive Fatigue

Aerospace jobs require sustained mental work for periods of up to several hours, often without intermittent rest periods. NASA astronauts perform mentally demanding intra- and extravehicular activities, which may last for several hours. Airline and military pilots fly continuously for hours at a time. Laboratory experiments and operational reports from situations like these show that performance and associated cognitive functions decline with time on task. The affected cognitive functions include alertness, attention, working memory, long-term memory recall, situation awareness, judgment, and executive control. In this study we were concerned with decrements in cognitive function arising during sustained mental work in a controlled laboratory experiment. We refer to these decrements as cognitive fatigue, to distinguish them from effects of sleepiness, motivation, learning, and physical fatigue. We define cognitive fatigue as the unwillingness to continue performance of mental work i