'Arousal' is a
physiological and
psychological state of being awake. It involves the activation of the
reticular activating system in the
brain stem, the
autonomic nervous system and the
endocrine system, leading to increased heart rate and blood pressure and a condition of sensory alertness, mobility and readiness to respond.
There are many different neural systems involved in what is collectively known as the arousal system. Four major systems originating in the brainstem, with connections extending throughout the cortex, are based on the brain's neurotransmitters,
acetylcholine,
norepinephrine,
dopamine, and
serotonin. When these systems are in action, the receiving neural areas become sensitive and responsive to incoming signals.
Importance
Arousal is important in regulating
consciousness, attention, and information processing. It is crucial for
motivating certain behaviours, such as mobility, the pursuit of nutrition, the
fight or flight response and
sexual activity (see
Masters and Johnson's human sexual response cycle, where it is known as the ''arousal phase''). It is also very important in
emotion, and has been included as a part of many influential theories such as the
James-Lange theory of emotion. According to
Hans Eysenck, differences in baseline arousal level lead people to be either
extraverts or
introverts.
The
Yerkes-Dodson Law states that there is a relationship between arousal and task performance, essentially arguing that there is an optimal level of arousal for performance, and too little or too much arousal can adversely affect task performance. One interpretation of the Yerkes-Dodson Law is the Easterbrook Cue-Utilisation hypothesis. Easterbrook states that an increase of arousal leads to a decrease in number of cues that can be utilised. (Easterbrooke, 1959).