Fear is a feeling induced by perceived danger or threat that occurs in certain types of organisms, which causes a change in metabolic and organ functions and ultimately a change in behavior, such as fleeing, hiding, or freezing from perceived traumatic events. An irrational fear is called a phobia. Fear can be uncomfortable and crippling. But eliminating it would be the equivalent of taking down your home alarm system because it sometimes makes loud and irritating sounds.
Fear is hardwired in your brain, and for good reason: Neuroscientists have identified distinct networks that run from the depths of the limbic system all the way to the prefrontal cortex and back. When these networks are electrically or chemically stimulated, they produce fear, even in the absence of a fearful stimulus. Feeling fear is neither abnormal nor a sign of weakness: The capacity to be afraid is part of normal brain function. In fact, a lack of fear may be a sign of serious brain damage.
Fear is part instinct, part learned, part taught. Some fears are instinctive: Pain, for example, causes fear because of its implications for survival. Other fears are learned: We learn to be afraid of certain people, places, or situations because of negative associations and past experiences.