As mentioned, earlier, one of the main functions of emotions is to motivate new behaviours. The arousal that accompanies emotions has a significant impact on things such as anxiety, performance stress and ultimately performance.

According to the Yerkes Dodson law, performance on a task depends on the amount of physiological arousal that we experience at any point together with the perceived difficulty of the task. This suggests that there is an ideal level of arousal for maximum performance in various situations. In order to perform well in an exam, a student needs to ensure firstly that they do not fall asleep. On the other hand, if the student is too nervous, they will be unable to focus on the set task and will also perform poorly.

Further studies have shown that there are a number of factors that influence the optimum level of arousal for an individual on any particular task.

Task Difficulty: For easy or simple tasks, a high level of arousal seems to be the best. In approaching simple math tasks such as simple addition, high arousal is best. More difficult tasks such as complex geometry are best performed with lower levels of arousal. This can also be applied to sports. Where a basketball player needs to run fast and bounce a ball in an automatic fashion, a good "psych up session" before the game can help. This can work in an adverse way when the same basketball player needs to stop and focus on a throw from the free throw line. In this instance, the player needs to be more in control. Being familiar with a task can help change what might be difficult into something that is perceived to be a little easier.

Task familiarity: If a task is familiar, a higher level of arousal will allow you to achieve optimum performance. The implication of this is that if you are the sort of person who gets really nervous before exams, you will cope much better if you know the material really well. This can also explain the amount of hype that goes on before a professional sports person hits the field. The basketball player who performs poorly at the free throw line would do well to have a lot of practice throwing from that spot so that they are familiar with the task.

Individual differences: Some individuals seem to work better under stress and will often seek out activities that create maximum levels of arousal. These are the sort of people who thrive on things such as sky diving and mountain climbing. Others prefer a more sedate way of approaching life. You need to work out where you think you fit.

Whether heading in to a sports event or an exam, it is important that you identify the best level of arousal to suit yourself. This will reduce anxiety and allow you to focus on the task as well as developing a sense that you are in control of what is going on at the time.