Understanding Why Humans Experience Fear
There are several different behavioral markers for fear, and the study of these markers is necessary for understanding why humans experience this emotional state. Although the most common eliciting stimulus is a scary sight, scientists have also quantified many of these responses. In laboratory studies, we can observe certain physiological responses, such as freezing, as well as increases in heart rate and startle. We can also measure alarm calls, which are species-specific and can help determine the level of apprehension in animals. Observers of human emotion can use these measures to further understand the origins of this complex experience.
When we experience fear, the brain sends signals to various parts of the body. This results in increased blood pressure, an increased heart rate, and a dilated pupil. We also experience sensations in the hands, legs, and stomach. These reactions are the result of an underlying memory-based expectation of a physical response. However, the exact nature of how these physiological signals are generated and why humans experience fear is still unknown.
When we experience fear, our brains respond by activating various nervous system modules. These mechanisms produce behavioral responses that are correlated with the intensity of the physical stimulus. As a result, we experience a range of behaviors. These responses are often the result of the primitive fear mechanism, which evolved to protect us from death. In spite of this, humans exhibit a wide variety of physical reactions to different types of threatening stimuli. Moreover, the different types of fear trigger different neural structures in our brains.