Signs of directed attention fatigue include temporarily feeling unusually distractible, impatient, forgetful, or cranky when there is no associated illness. In more severe forms, it can lead to bad judgment, apathy, or accidents, and can contribute to increased stress levels. DAF is caused by concentrating too much in the midst of external or internal distractions. Inhibitory attention chemicals are replenished during sleep, so lack of sleep can increase the likelihood of directed attention fatigue.
Researchers studying directed attention fatigue: