Fear is an emotional response to threats and danger. It is a basic survival mechanism occurring in response to a specific stimulus, such as pain or the threat of pain. Psychologists John B. Watson and Paul Ekman have suggested that fear is one of a small set of innate emotions. This set also includes joy, sadness, and anger.
Fear should be distinguished from 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.