Fear is an emotion that all human beings possess, which at times we see as a feeling and we don't even know why we feel it. However, we do not know that it is a state of the brain or neuroendocrine system, which arises under certain conditions and manifests by certain forms of behavior. Fear can be seen from different points of view. From the biological point of view, fear is an adaptive scheme, and constitutes a mechanism of survival and defense, arisen to allow the individual to respond to adverse situations with speed and efficiency.