Fear is a psychological concept that is used to describe the cluster of behaviours that are observed and experienced when a human being faces a threatening situation. If suddenly confronted by a stranger holding a gun to your face, you will realize instantly that you are in danger, that you could be beaten or even killed. Your hands will sweat, your heart will pound and your mouth will feel very dry. You will begin to tremble and feel as if you can’t catch your breath. You may feel the hair standing out on the back of your neck and your mind will race, trying to decide whether to hold still, to run, or to try to take the gun out of the assailant’s hand. Your sense of smell, sight and hearing will increase and your pupils dilate. Later you will remember this terrible incident over and over again, seeing your assailant’s face or the gun in vivid detail. Returning to the location where the incident occurred will revive those awful memories often to the point where you will want to avoid that place forever (see PLACE CONDITIONING).
Thus fear is a complex set of reactions which include both the expression and the experience of the emotional event (see EMOTION). Sweaty palms, increased heart rate, altered respiration, hair standing on end, and dilated pupils are part of the expression of fear. The feelings of dread, of potentially being killed, of your heart pounding or the hair standing upright on the back of your neck, are part of the EXPERIENCE of fear. Such reactions depend on the activation of the SYMPATHETIC NERVOUS SYSTEM. Very similar reactions can be seen in animals. If a cat confronts a vicious dog, the cat will assume the familiar ‘Halloween posture’ with its back arched, hair standing on end, and teeth bared. These expressions of fear can be seen easily and measured objectively. One can presume, based on our own experience, that the cat is experiencing a feeling of fear and a threat to its survival. However, unlike humans, where it is possible to discuss the experience of fear and how it feels, we can only infer that the cat is feeling fearful from looking at the situation and the set of behaviours it displays.
