Arousal is the amount of energy we invest in the attention process and hence perception.
Our focus in life can be seriously blunted if we lack the motivation to set our goals in action, whether it is to build a skyscraper, or select all the odd numbers from a numerical array.
Since perception is a process that often requires "work" on the part of the individual, a lack of motivation could seriously diminish the effectiveness of the perceptual process. This also relates to our level of arousal.
Arousal has to do with the amount of ãenergyä we have available, or choose to put into the process of perceiving. Involved here, in addition to motivation, is the integrity of the Reticular-Activation System.
This controls our state of wakefulness, and can range from a coma to a state of hyper-excitability (epileptic seizure).
The degree of arousal is related also to he degree of perceptual organization achieved.