Not only humans but many other organisms have fear responses when perceiving threat or danger, causing a metabolic reaction in organ function which in turn changes the behavior such as fleeing or freezing. A fear can be rational or irrational (phobia). According to psychologists John B. Watson and Paul Ekman there are only a few innate emotions of which fear is one. The fear response, because it serves survival, has been very useful throughout evolution.
“Fear Appeal” is used in sociology, psychology and especially marketing. The strategy used is to motivate people to take part in an action, to join a movement, accept a particular policy, or buy a product, by exploiting fear. Fear Appeal is the use of a message arousing fear to influence behavior. Fear is an unpleasant emotion that motivates behavior to reduce anxiety, alleviate the threat and reduce the fear. This ‘’fear appeal’ is widely used, not only in religion but also in political campaigns, and can be positive, such as in public health and safe driving campaigns. In other cases such as politics, religion and conspiracy theories, fears are used to control a great number of people, undermining logic, facts and critical thinking.
FUD, Fear, Uncertainty and Doubt, is a disinformation strategy to influence perception through dubious or false information used in sales, marketing, public relation, talk radio, religious organizations and political propaganda and has become broadly used in the internet (see Wikipedia). A great example of that is the anti-vaccination movement encouraged by the publication of Andrew Wakefield’s discredited claims of vaccine causing autism. Although all political parties use FUD to attract votes, the Current POTUS and the GOP have been spectacularly successful using this strategy during the last election.
Religion arose because of the innate desire to have an answer to the unexplained to alleviate the fear of the unknown. It has used fear very effectively to control the “tribe” to the benefit of the leaders. Many believers, concerned about others, fear that some of their loved ones and friends are doomed after death, and therefore try to convince others to join them in their belief system. Although well meant, it often has the opposite effect by ruining friendships and tearing families apart. It is therefore very important that “critical thinking” is promoted at an early age, so that the menace of unwarranted fear, such as the fear of God and Hell, is eliminated.