[1][page needed] 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.
Studies that require participants to carry out attention-demanding tasks under conditions of high distraction reveal how unpleasant a mentally fatigued person can be.
Signs of Directed Attention Fatigue include temporarily feeling unusually distractible, impatient, forgetful, or cranky when there is no associated illness.
[citation needed] There are 6 major areas of mental processing that are affected during onset of DAF, which are as follows:[4] Overlap of symptoms from the six above categories is highly indicative of Directed Attention Fatigue.
Experimentation has shown that the severity of ADHD symptoms can be correlated to the degree of asymmetry between blood flow in the left and right prefrontal cortex.
[citation needed] The onset of directed attention fatigue can be triggered by a number of activities involving the use of the brain's inhibitory system.
Activities that engage this system include multitasking,[7] working in an environment with disruptive background noise,[citation needed] a lack of sleep,[8] and rapidly changing focus during a prolonged period of attention.
This type of attention employs the inhibitory mechanisms of the brain, which help block incoming stimuli that are unrelated to the task at hand.
For a mentally fatigued person, paying attention to something uninteresting is burdensome, even though focusing on something of great interest poses no particular challenge.
Research has shown that restorative experiences, such as clearing one's head and reflecting on one's life and priorities, may help combat Directed Attention Fatigue.
Similarly, it has been discovered that even brief amounts of time spent on a busy metropolitan street can affect one's ability to maintain focus on a given task.
Results also demonstrate that communities with several trees and other natural areas tend to be stronger, safer and house residents with a higher attention level.
Such studies suggests that the DAF experienced by cancer patients following surgery improves significantly through outdoor restorative activities for 20 minutes per day.