Directed attention fatigue (DAF) is a neuro-psychological phenomenon that results from overuse of the brain's inhibitory attention mechanisms, which handle incoming distractions while maintaining focus on a specific task. The greatest threat to a given focus of attention is competition from other stimuli that can cause a shift in focus. This is because one maintains focus on a particular thought by inhibiting all potential distractions and not by strengthening that central mental activity. Directed attention fatigue occurs when a particular part of the brain's global inhibitory system is overworked due to the suppression of increasing numbers of stimuli. This temporary condition is not a clinical illness or a personality disorder. It is rather a temporary fatigue of the inhibitory mechanisms in the brain. According to inhibition theory, it is natural for one to alternate between periods of attention and distraction. Although one's efforts may involve very different tasks, each incoming stimulus calls upon the same directed attention mechanism. Symptoms Extreme levels of mental fatigue lead to an inability to perform regular tasks and irritability. Studies that require participants to carry out attention-demanding tasks under conditions of high distraction reveal how unpleasant a mentally fatigued person can be. After exposure to such an experience, individuals are less likely to help someone in need. They are also more aggressive, less tolerant, and less sensitive to socially important cues. Fatigue that is experienced by participants of these kinds of studies is induced by attention-intensive tasks, and the observed effects of such fatigue are correlated with decline in inhibitory control. 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. There are 6 major areas of mental processing that are affected during onset of DAF, which are as follows: Input — One may experience misperception and miss social cues. Thinking — One may experience feelings of restlessness, confusion, forgetfulness and/or decreased metacognition. Behavior — One may experience feelings of impulsiveness and recklessness, and may find that they have a diminished level of threshold between thoughts and actions. One may also act out-of-character. Executive Functioning — One may experience an inability to plan and make appropriate decisions and may experience impaired judgment ability. Emotions — One may experience being short-tempered and feelings of unpleasantness. Social