Fear: Definition, Symptoms, Traits, Causes, Treatment

Fear is a natural and primitive emotion that can be experienced by everyone to some degree.

Fear alerts us to the presence of dangers, whether they be real dangers or perceived.

People may experience fear when in situations such as walking home alone at night, facing animals they perceive as dangerous, or when about to skydive out of a plane.

Fear can also be attributed to feelings of stress and anxiety. It may also contribute to some feelings of disgust, as according to a study investigating those who feared or did not fear snakes, those who experienced this fear reported high feelings of disgust and fear (Rádlová et al., 2020).

Biochemical Reaction

Fear is a normal response to many situations and is composed of two primary reactions: biochemical and emotional reactions.

The biochemical reaction to fear causes our bodies to respond to perceived threats in the environment.

This produces automatic physical reactions such as sweating, increased heart rate, breathlessness, and dilated pupils. The purpose of these bodily reactions is to prepare the body to either combat the threat or to run away from it – this is called the ‘ fight or flight ’ response.

In response to a threat, the sympathetic nervous system, part of the autonomic nervous system, is activated by the sudden release of hormones.

The sympathetic nervous system then stimulates the adrenal glands to trigger the release of hormones, resulting in physical reactions. These hormones are:

• Epinephrine (adrenaline) – Provides energy to the major muscles of the body so they can respond to a perceived threat.
• Norepinephrine (noradrenaline) – increases alertness, arousal, and attention. Connstricts blood vessels that help maintain blood pressure during times of stress.

Emotional Response

The emotional response to fear, however, is personalized to the individual. Since the biology of fear involves some of the same chemical responses to positive emotions, such as excitement and happiness, people can experience either positive or negative emotions to fear.

For instance, some people may find enjoyment in riding extreme roller coasters, whilst others may have a negative reaction and will avoid these at all costs.

Although the biochemical reaction for fear may be the same, some people will experience the intensity of fearful situations differently than others.

Is fear useful?

In many situations, fear is normal and healthy in that it can keep us from entering harmful situations and help us decide when to get out of these situations.

The immediate threat of danger and the physical responses that come with it can help focus our attention and mobilize us to cope with the danger but either fighting against it (fight) or running away from it (flight).

Fear may also help us to react to danger without having to think about it consciously.

For example, if a car is coming towards us, fear can make us jump out of the way and thus save our lives. Also, if humans have the capacity to notice fear in others since we recognize it in ourselves, we can offer compassion and reassurance to others to help them cope.

In contrast, extreme levels of fear could result in the development of mental health conditions such as phobias or other anxiety conditions. A phobia is an intense, persistent, and out of proportional fear of something, an event, or a situation.

Phobias twist the normal fear response into something difficult or impossible to control and can be detrimental to people’s lives. Likewise, other anxiety conditions, such as generalized anxiety disorder and social anxiety disorder, involve intense worry or fear of many things and social situations respectively.

The biochemical and emotional response to fear can be so extreme that it can negatively affect people’s lives. If fear gets too extreme, such as in those experiencing anxiety disorders, it can keep us trapped, preventing us from doing things we want.

Types of Fear

Causes of fear

Specific phobias, usually develop in childhood and, in some cases, can be pinpointed to an exact moment.

In some cases, specific phobias can result from an early traumatic experience with the feared object, event, or situation, such as a phobia of bicycles caused by a traumatic incident of falling off a bike as a child.

Phobias that start in childhood could also be caused by witnessing the phobia of a family member and developing the same phobia. For instance, if a parent has a phobia of spiders, the child may also learn to have a phobia of spiders.

Evolutionary theory of fear

Seligman (1971) applied his preparedness hypothesis theory to explain why humans fear. The preparedness hypothesis is the belief that humans have a tendency to fear things that were a source of danger to our ancestors.

Seligman proposed that the fears of individuals who are diagnosed with phobias reflect the evolutionary prepared learning to fear events and situations that have provided survival threats.

He argued these threats would be from an evolutionary rather than a contemporary perspective.

This can be used to explain why phobias such as threatening animals, heights, closed spaces, and social evaluations are very common and appear to be innate fears.

Whilst contemporary fears such as bicycles, broken electrical equipment, and guns as less common as these would not have been survival threats to our ancestors.

The preparedness hypothesis suggests that humans can have innate responses to specific stimuli without any previous environment input.

This has been tested by scientists who found it was easier to train humans to fear snakes and spiders than friendly dogs of pillows, for instance.

This was found to be especially true for very young children who appeared to fear snakes and spiders before encountering or hearing about them.

Fear conditioning

Pavlovian fear conditioning is a state of fear or anxiety that has been demonstrated in animals after repeated pairings of a threatening stimulus with a previously neutral stimulus using classical conditioning.

In experiments, the researchers would pair a neutral stimulus with an unpleasant stimulus – such as a loud noise or shock. After repeated pairing of these two stimuli, the neutral stimulus on its own would eventually elicit a state of fear.

This is another way in which intense fear could be caused. The fear expressed by the animals would be seen as essential for their survival in this instance.

This fear conditioning could be learned in humans who suffer from posttraumatic stress disorder (PTSD).

Post-traumatic stress disorder (PTSD) is an anxiety disorder caused by very distressing, frightening, or traumatic events, causing individuals to relive them through symptoms of intense or prolonged psychological distress when triggered. This includes marked physiological reactions such as exaggerated and unrelenting unconditioned responses to stimuli (e.g., crowds, flashes of light, or sounds) that are associated with trauma (e.g., death or injury).

PTSD can bring about feelings of intense fear when something specifically triggers it. Most of the time, the trigger will not be an actual threat to survival but is a conditioned stimulus for the individual.

This means they can experience intense feelings of fear at times when it is not appropriate.

The brain’s fear response

The primary brain region that is responsible for fear is the amygdala. The amygdala is a collection of nuclei in the limbic system.

Some of the main nuclei in the amygdala are the lateral, basal, central lateral, and central medical nuclei. The lateral nucleus is the primary input that receives input from the thalamus and the brain’s cortex, providing it with information about the sensory stimuli being experienced.

The primary output nucleus of the amygdala is the central medial nucleus which projects to different structures, such as the paraventricular nucleus of the hypothalamus, which triggers the release of the stress hormone cortisol.

It also projects to the lateral hypothalamus to stimulate the autonomic nervous system, which results in the physiological symptoms associated with the fight or flight, or fear, response.

The amygdala is also thought to be the area of the brain responsible for fear conditioning. In rats, it was found that an unconditioned stimulus, such as a shock, is picked up by the spinal cord, which sends this signal to the thalamus and the cortex, which then both project to the lateral nucleus of the amygdala.

The synaptic inputs from the unconditioned stimulus are strong enough to excite the lateral amygdala neurons, which results in the activation of the neurons in the central medial nucleus and thus produces a fear response.

Sensory information from a neutral stimulus (e.g., music) also reaches the thalamus and cortex. Still, the inputs from this stimulus are not strong enough on their own to excite the lateral amygdala neurons, so the central amygdala neurons remain unstimulated, and there is no fear response.

However, if the neutral stimulus (music) is paired with the unconditioned stimulus (shock), both can be encoded by neurons simultaneously. This can strengthen the synapse between incoming neurons carrying information about the neutral stimulus and the lateral amygdala neurons.

Eventually, this synapse is strengthened enough to allow them to stimulate the lateral amygdala neurons on their own without the unconditioned stimulus. The lateral nucleus will then excite the central medial nucleus to produce the fear response.

The hippocampus, which plays a role in storing episodic memories, can also interact with the amygdala and be involved in fear. The neurons from the hippocampus can project to the basal nucleus of the amygdala, which can then stimulate the central medial nucleus.

Because it can do this, the hippocampus allows contextual-related memories to respond to fear. This could be why we can have fearful memories and why they are so strong.

There are suggested to be sex differences in amygdala activation.

A study that used the brain imaging technique of functional magnetic resonance imaging (fMRI) found that when presented with happy facial expressions, there was greater activation in the right amygdala for males but not for females.

Both males and females showed greater left amygdala activation for fearful faces, which supports that the left may be more involved in negative affect (Killgore & Yurgelun-Todd, 2001).

Other researchers have found that the volumes of brain regions involved in fear may differ for those who have experienced more trauma.

Using MRI on children who experienced trauma, research found reduced hippocampal and increased amygdala volume with increasing levels of trauma exposure. Higher exposure to violence was also found to be associated with increased amygdala activation.

Finally, increased functional connectivity between the amygdala and the brain stem was associated with higher levels of exposure to violence (Van Rooij, et al., 2020).

Treatment and management

Treatments for phobias can often be used for conditions associated with extreme fear and cause significant impairment in daily functioning. These usually involve graded exposure therapy, which involves repeated exposure to the feared situation gradually to slowly minimize and adapt to the fear response.

This was demonstrated in studies with rats who had been trained to have a conditioned fear response to a stimulus. The researchers would eventually stop pairing the unconditioned stimulus (such as a shock) with the now conditioned stimulus (such as music); they would only present the conditioned stimulus.

After repeated exposure to the conditioned stimulus, the rats eventually had neutral feelings toward it once realizing that nothing bad was going to happen, so it became a neutral stimulus again.

References

Killgore, W. D., & Yurgelun-Todd, D. A. (2001). Sex differences in amygdala activation during the perception of facial affect. Neuroreport, 12(11), 2543-2547.

Öhman, A. (2009). Of snakes and faces: An evolutionary perspective on the psychology of fear. Scandinavian journal of psychology, 50(6), 543-552.

Rádlová, S., Polák, J., Janovcová, M., Sedláčková, K., Peléšková, Š., Landová, E., & Frynta, D. (2020). Emotional reaction to fear-and disgust-evoking snakes: sensitivity and propensity in snake-fearful respondents. Frontiers in psychology, 11, 31.

Seligman, M. E. (1971). Phobias and preparedness. Behavior therapy, 2(3), 307-320.

Steimer, T. (2002). The biology of fear-and anxiety-related behaviors. Dialogues in clinical neuroscience, 4(3), 231.

van Rooij, S. J., Smith, R. D., Stenson, A. F., Ely, T. D., Yang, X., Tottenham, N., Stevens, J. S. & Jovanovic, T. (2020). Increased activation of the fear neurocircuitry in children exposed to violence. Depression and anxiety, 37(4), 303-312.