Arousal, or an individual’s general level of central nervous system excitement and activation, plays a noteworthy role in the ability to achieve tasks both rapidly and precisely. The inverted U value further clarifies the relationship between arousal and performance. The inverted U hypothesis postulates that arousal assists performance to a certain degree. If the arousal level is too low or too high, the individual fails to yield high-level performance. The zone of optimal functioning, or simply ‘the zone’, is the level of arousal for the best mixing of both the physical and mental practices linked with maximal performance. It is represented by a number of factors, counting improved automaticity (autopilot) and the augmented ability to pinpoint task-relevant cues and to pay no attention to environmental cues that are irrelevant to performance. Normally, if a person’s arousal levels are too low, they may focus too much on inappropriate environmental prompts. Since their environmental effort may be too broad, these perceptual interferences may not allow them to pick up on pertinent environmental stimuli. Perceptual narrowing, or tunnel vision, may also happen as arousal levels carry on rising. This may hamper the individual’s ability to detect task-relevant cues, thus protracting reaction time. In an ideal world, the individual can ascertain the optimal level of arousal necessary to switch focus from broad to narrow. For instance, when a tennis player serves a ball, he or she, to begin with, has a broad focus as he or she scans the court to decide where he or she would like to serve the ball. Then a shift to a tapered focus would occur during the serve. Once the serve is done, another shift to a broader focus transpires in order to track their adversary and to anticipate where the challenger will return the ball.