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Fear is a distressing emotion aroused by a perceived threat. It is a basic survival mechanism occurring in response to a specific stimulus, such as pain or the threat of danger. Some psychologists such as John B. Watson, Robert Plutchik, and Paul Ekman have suggested that fear belongs to a small set of basic or innate emotions. This set also includes such emotions as joy, sadness, and anger. Fear should be distinguished from the related emotional state of anxiety, which typically occurs without any external threat. Additionally, fear is related to the specific behaviors of escape and avoidance, whereas anxiety is the result of threats which are perceived to be uncontrollable or unavoidable.[1] Worth noting is that fear almost always relates to future events, such as worsening of a situation, or continuation of a situation that is unacceptable. Fear could also be an instant reaction to something presently happening.



A vivid description of fear was provided by Charles Darwin in his book, The Expression of the Emotions in Man and Animals:

The most common physical reactions of fear include:

  • Rapid heart rate
  • Increased blood pressure
  • Tightening of muscles
  • Sharpened or redirected senses
  • Dilation of the pupils (to let in more light)
  • Increased sweating[citation needed]

The facial expression of fear includes the widening of the eyes (out of anticipation for what will happen next); the pupils dilate (to take in more light); the upper lip rises, the brows draw together, and the lips stretch horizontally. The physiological effects of fear can be better understood from the perspective of the sympathetic nervous responses (fight-or-flight), as compared to the parasympathetic response, which is a more relaxed state. Muscles used for physical movement are tightened and primed with oxygen, in preparation for a physical fight-or-flight response. Perspiration occurs due to blood being shunted from body's viscera to the peripheral parts of the body. Blood that is shunted from the viscera to the rest of the body will transfer, along with oxygen and nutrients, heat, prompting perspiration to cool the body. When the stimulus is shocking or abrupt, a common reaction is to cover (or otherwise protect) vulnerable parts of the anatomy, particularly the face and head. When a fear stimulus occurs unexpectedly, the victim of the fear response could possibly jump or give a small start. The person's heart-rate and heartbeat may quicken.

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