Arousal

Arousal is a physiological and psychological state involving 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 alertness and readiness to respond.

It is a crucial process in motivating certain behaviours, such as 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 thought to be crucial in emotion, and has been an important aspect of theories of emotion since early models such as the James-Lange theory of emotion.

The Yerkes-Dodson law is an empirical law which states 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. An oposing Approach to the Yerkes-Dodson law is the Easterbrook Cue-Utilisation hypotheses. Easterbrook states that an increase of arousal leads to a decrease in number of cues that can be utalised. (Easterbrooke, J.A. (1959). The effect of emotion on cue utilization and the organization of behavior. Psychological Review, 66, 183-201)