The Primal Fear: Is It Our First Emotion?

Fear is an innate emotion that is one of the last to emerge in humans, usually at around 6-7 months old. It is a protective and primal emotion that prepares the body for action, whether that be to confront the danger or run away.

The physical response to fear is universal, with the body undergoing specific changes such as sweating, increased heart rate, and high adrenaline levels. This is known as the 'fight or flight' response, which is thought to be an evolutionary development.

The emotional response to fear, however, is highly individualised. Some people are adrenaline seekers, thriving in situations that induce fear, whereas others will avoid fear-inducing situations at all costs.

Fear can also be a symptom of some mental health conditions, including panic disorder, social anxiety disorder, phobias, and post-traumatic stress disorder.

The evolutionary function of fear

Fear is both a natural emotion and a survival mechanism. When confronted with a perceived threat, the body responds in specific ways, including sweating, increased heart rate, and high adrenaline levels that cause extreme alertness. This physical response is also known as the fight-or-flight response.

Fear is also modulated by the process of cognition and learning. It can be judged as rational and appropriate, or irrational and inappropriate (or unconscious). An irrational fear is called a phobia.

Fear is closely related to the emotion anxiety, which occurs as the result of often future threats that are perceived to be uncontrollable or unavoidable.

Fear is an innate response for coping with danger, and it works by accelerating the breathing rate (hyperventilation), heart rate, vasoconstriction of the peripheral blood vessels leading to blood pooling, dilating the pupils, increasing muscle tension, sweating, increased blood glucose (hyperglycemia), increased serum calcium, and increasing white blood cells called neutrophilic leukocytes. This primitive mechanism may help an organism survive by either running away or fighting the danger.

Fear is also implicated in a number of mental disorders, particularly anxiety disorders.

The physiological changes caused by fear

The following physiological changes occur when an individual experiences fear:

• Breathing rate increases (hyperventilation)
• Heart rate increases
• Vasoconstriction of the peripheral blood vessels, leading to blood pooling
• Pupils dilate
• Muscle tension increases, including the muscles attached to hair follicles, causing "goosebumps"
• Sweating increases
• Blood glucose levels increase (hyperglycaemia)
• Serum calcium levels increase
• White blood cell count increases, particularly of neutrophilic leukocytes
• Alertness increases, which can lead to sleep disturbance
• Stomach discomfort ("butterflies in the stomach" or dyspepsia)

The role of the amygdala in fear

The amygdala is a key component of the brain's fear circuitry, playing a central role in processing fear-related stimuli and coordinating fear responses. It is involved in both the recognition and experience of fear, with lesions in this area resulting in impaired fear responses.

The amygdala receives sensory inputs that specify fear associations, primarily through the basolateral amygdala. Selective activation of neurons within this nucleus is sufficient to associate incoming sensory information with unconditioned fear responses. The central nucleus of the amygdala is considered the main output regulator for mediating fear responses, with distinct subdivisions coordinating freezing, flight, and fight behaviours.

The amygdala is highly interconnected with other brain regions, including the prefrontal cortex, hypothalamus, periaqueductal grey, and brainstem nuclei. This network enables the integration of sensory information, cognitive processes, and fear responses, demonstrating the amygdala's crucial role in orchestrating an adaptive response to threatening stimuli.

Studies have shown that the amygdala is activated not only by fear and anxiety but also by a broad range of stimuli, including highly arousing appetitive stimuli. This has led to the proposal that the amygdala's role in fear may be one example of a broader function, such as processing arousal, value, relevance, or vigilance.

In summary, the amygdala is a critical component of the brain's fear circuitry, receiving sensory inputs, coordinating fear responses, and interacting with multiple brain regions to modulate emotional responses. Its function extends beyond fear processing, highlighting its role in various cognitive and behavioural processes.

The facial expression of fear

The evolutionary preset actions of fear include fight, flight, and freezing. While traditionally considered a "negative" emotion, fear serves an important role in keeping us safe by forcing us to react without thinking.

The vocal expression of fear

The experience of fear is universal, but the emotional response is highly individualised. While fear typically arises from the perception of physical or psychological danger, it can also be triggered by imaginary or anticipated threats. This emotional response is influenced by factors such as cultural and historical context, as well as individual experiences and associations.

Fear is a protective emotion that serves a crucial role in survival. The vocal expression of fear is an integral part of this survival mechanism, allowing individuals to alert others to potential threats and mobilise collective action. This aspect of fear highlights the social nature of the emotion, which extends beyond individual experiences.

Frequently asked questions