Another proposed explanation as to the cause of ADHD is that the brains is unable to filter or compartmentalise the masses of information it receives from all the different senses at any one time. In everyday life, the human brain is subjected to information and stimulation from a vast array of sources; from a teacher talking, to the smell from the kitchen, to the view outside the window.
A person suffering from ADHD has great difficulty attending only the relevant information it is receiving and blocking irrelevant stimulation from all other sources. It has been argued that rather than a person who is suffering from Attention Deficit Hyperactivity Disorder not paying enough attention, they instead try to devote too much attention to too many sources and subsequently appear to wander on different thought planes. Subsequently, they are unable to sustain focus for extended periods of time.