Fear is the emotion people experience when danger is perceived. It’s the oldest and most unreasonable of all emotions, yet its aim is always to prevent harm.

The first time people become conscious of a fear, it’s reached through astonishment of a negative thing. When a person is astonished, the instinctual reactions are a preparation for another emotion. Astonishment is the standard instinctive reaction to suddenly perceived events, which usually last milliseconds, that morphs into fear when the sudden event is perceived as negative.1
Negative emotions in general narrow attention, but fear redirects and constrains attention to serve fast defensive needs more than any other emotion.2 Fear has immediate and virtually direct control over many neuro-biological systems. Heart rate and blood flow can significantly speed up or slow down depending on perception alone.3
Freezing is an automatic response that takes over psychological processes and redirects attention to scan for a perceived object of fear. Physiological function is instinctively commanded by skeletal muscles to freeze in an appropriate position. A person could crouch or cower while the back moderately hunches into a strangely shaped shrug-like posture. Animals, including humans, often freeze in positions that offer the most camouflage. Immobility is likely to prevent detection from animals whose sight mostly depends on movement. Running increases risk in some situations by releasing a predator’s attack response. Different perceptions will bring about different responses instinctively. Freezing is not a mere absence of movement; it’s an instinctive, evolutionary, rehearsed act.4

If escape is the best option, the heart rapidly palpitates. Pressure increases in the circulation system for pumping oxygenated blood around the body fast. As blood flow is decreased by closing capillaries, areas such as the hands and face become cold while their skin becomes pale, and blood pressure increases in the main vascular system. The legs then become warm from an increased blood flow as they’re prepared for running. Typically, the neck and torso muscles move the head away from the perceived threat. Hormones and neurotransmitters prepare the body for action. Hands may shake as the muscles are primed with twitchiness.
These automatic expressions of fear become more uncontrollable, unpredictable and erratic as the emotion increases its intensity and reaches its extreme towards terror. This is partially because humans instinctively prepare for an event according to its perceived intensity more than its probability.5 Humans instinctively alter their physiological, neurological and psychological processes to best deal with their most intense perceptions. A change in disposition occurs whether the perceptions are an accurate account of reality or not. As long as people believe a perception is true, they instinctively prepare for it. The more intense their perceptions become, the less control people have over these automatic dispositional responses. Emotions progressively assume control of behaviour as they reach towards their limits of intensity.6

Fear has been a response to dangerous evolutionary contingencies for hundreds of millions of years.7 Fear responses were evolving throughout the dinosaur era. It is a primary emotion that is highly associated with the earliest of brain structures – such as the brainstem. At the same time, fear is also entwined in the newest of brain structures, the right prefrontal lobe, which initiates highly evolved social emotions that dominate human interpersonal decisions.8
Cognitive decisions will be biassed away from taking risks whilst fear is experienced. Psychological outlook is primed towards recognising ways out, escape routes, of the situation. Risk is the very thing that fear motivates people to avoid.
The newer brain structures are an extension of the older ones. The older structures are necessary for the newer more highly evolved structures to work. Core consciousness depends on the evolutionary older brain structures. Higher faculties and high-definition notions of self rely on the newer structures such as the neo-cortex. If humans lose higher brain structures, and their associated faculties – say through brain injury, core consciousness still remains, and functionality would only be reduced. On the other hand, if humans lose the evolutionary old structure called the brainstem, they have no sense of self and remain in a vegetative state or die.9
The brain is formed by many interactive systems that all work together. Systems are seamlessly creating connections between information from conscious and subconscious realms. The brain presents its finding to the imagination on request of a thought in milliseconds (here is a video, Reason vs Perception, which includes examples). Every memory recall, every word spoken, every solution found is made possible by this process. The entire seamless high-faculty processing, that makes intelligence so distinctive, depends critically on older brain structures. Old and new are ultimately one. They even work as one. Nonetheless, as one is built on the foundation of the other, one of them (social emotions/neo-cortex) cannot work without the other (primary fear/brainstem). Fear is such a foundation to consciousness.

Implicit-memory refers to perceptions that have been stored subconsciously. The amount of unconscious perceptual data is more than humans could imagine, and far beyond anything we could consciously control. As this unconscious data includes automatic lung activation for breathing, heart rate, blood pressure homeostasis, and many other biological processes that are necessarily kept out of conscious control, much of this procedural memory is wholly inappropriate for people to control consciously. Even if, by some miracle, they managed to attain the conscious processing power required to do so, a deadly risk would be taken.
Access to these memories is extremely restricted. The ones that are at the top (nearest conscious explicit-memory) of this overwhelming mass of perceptual data are on the tip of one’s tongue, or on the edge of awareness. Be that as it may, people can consciously select activities for unconscious automation. Without people realising it, perceptions build into a store of experiential data, until one day they can suddenly perform a complex task without having to think about it. Perceptions of the activities people do frequently amass to be used to re-enact complex activities without conscious attention. Whether it’s learning the piano or surfing a wave, people can programme their subconscious by habitually repeating an activity.
As people repeat behaviours over a few hundred thousand years, they develop very precise instinctual reactions to specific events. The reactions are based on a gigantic mass of implicitly stored perceptions. In essence, instinctive reactions are appropriate to the environment in which they developed. Fear has been an instinct for hundreds of millions of years. A mass of data is bundled into distinctive implicit-memories that initiate specific neuro-biological processes when perceptions of a pattern (emotionally competent stimulus) fit the memory’s profile.10 These are experienced as instincts. A cascade of specific psychological, neurological and biological reactions take place as the emotion of fear manifests in response to a perceived threat. This perceptual representation is pre-semantic: the profile of a threat can be recognised before people have any conscious awareness of it.11

Human integration of fear, throughout evolution, means that it has been hard-wired to the most dramatic biological responses. Fear is a highly evolved emotion associated with thought. To say that fear multi-tasks is a colossal understatement. Fear is felt when intellectually considering possible situations that are extremely complex and sensitive in nature. The range of fear’s intensity is tremendous. It’s an instinctual response that outranks other instincts whilst being an inherent aspect of many other emotions: anger, jealousy, contempt, disgust, terror and ferocity to mention a few. It has a massive amount of influence over reasoning and habits. It makes people sensitive and protective in nature. Fear, for millions of years, has related directly to mortality and the ability to avoid life-threatening scenarios. When intense fear is felt, similar implicit-memories of the same intensity will be recalled that refer to serious life-threatening situations. The fear is ranked so highly, in people’s way of relating to the world, that it will cut through anything else they’re engaged in. It has priority status.
This is why fear is so useful when faced with danger, yet it’s also the very reason why abusers use it as a form of control. If people think serious danger is associated with a particular path, they will not continue to do that thing unless it’s something so valuable that they are willing to face death. The majority of people, adults and children, would much rather avoid seriously dangerous situations for a danger- and stress-free life.
Fear is appropriate when the perceptions that create it are true. Accurate perceptions of threats in the environment create emotions that are appropriate to the reality of the situation. This is a healthy process that enables people to assess and react to real threats. It also enables people to develop an understanding of patterns that occur in life regarding ill-health and mortality, so fear is a healthy and necessary emotion that primarily helps people prosper.
Problems start when people are convinced that something is more, or less, dangerous than it really is. The inaccurate perception causes emotions that are out of proportion to the reality of the situation. This leads to over- or under-reactions. People will overestimate or underestimate the danger in a situation. This means that they will either be too willing to fight, too eager to run, or simply be caught out because they did not appreciate the seriousness of the threat. Phobias and anxiety disorders are examples of how inaccurate perceptions of danger can create too much fear for a given situation.

Fear is an exceptional motivator, and it’s incredibly volatile. It can lead to the most unreasonable and irrational actions being taken. This is commonly seen in everyday situations when people panic unnecessarily. Psychological panic can create havoc with thoughts, behaviours and biological processes. If inaccurate perceptions of danger are believed on a prolonged basis, it will create stress on neuro-biological and psychological systems. People’s instinctive reactions to fear include heart rate, blood pressure, hormone and neurotransmitter production changes that are meant to accommodate short periods of adaptive activity to shift attention to concentrate on a threat. If a maladaptive response is experienced continually, the organs and systems involved in processing a reaction to that state, and the ones that are neglected due to the preoccupation, will be impaired by accumulated stresses called allostatic-load (see Stress). Such allostatic-load from continued stress results in serious health conditions, and it’s been shown in longitudinal research to predict cardiovascular disease, later life decline in physical functioning and memory loss.12 Allostatic-load has been linked to high cortisol levels, high risk of cancer and speeding disease progression.13This is the striking truth of fear. It can motivate people in a split second to do incredibly desperate and violent things, yet it can paralyse people and cause disease if chronically experienced. When a threat is perceived to be immediate and real, the thoughts that surround the threat will be the thoughts that press themselves for recognition in mind. Until the threat has gone, fearful responses remain.
The effects of fear from traumatic experiences should not be underestimated. Memories last a lifetime, and this is a serious matter for people who suffer from post-traumatic stress disorder. Especially, when considering that the intensity of a perceived event outweighs the probability of it occurring, instinctive changes automatically manifest as people’s dispositions are transformed in preparation for an intense event; just in case it happens.
Natural dangers like mountains, extremely cold weather or wild animals are generally less frequent and less continuous than the numerous relationships most people hold. Most people can go without knowing the serious dangers of walking in the mountains because most people will never be in the situation where they need to know. Only, most people have relationships. To underestimate the dangerous characteristics that another has is to leave one’s self vulnerable to those people whenever they are around – vulnerable to potentially terrifying images embedding in memories which last a lifetime.

A healthy sense of fear is a good thing that has the potential to keep people out of harm’s way on a physical, emotional and psychological level. Although, as with most instincts, it pertains more to survival in a far more physical and violent evolutionary environment. People can more easily judge threats expressed through body language than gauge the threats of complex social behaviours. The time humans have spent, millions of years, focusing on these physical parameters of survival far outweighs two thousand years of civilised society. Nevertheless, the balance of people’s emotional state depends on the accuracy of their perceptions of dangers. Humans are learning to judge what threatening behaviours reside in a new, civilised, highly social and close-knit world.
As fear is the oldest of emotions, it has the deepest and broadest of influences over biological, physiological and psychological experience. Intense fear is capable of initiating the most primal of deadly feelings – such as terror and ferocity – while mild fear guides people with feelings of concern. Fear is intimately integrated into the highest faculties humans possess. Despite the traumatic side-effects fear can cause, its purpose is always to protect.


Latin. Periculum = trial, risk, danger.

1. A sudden and terrible event; peril.

2. The emotion of pain or uneasiness caused by the sense of impending danger. A state of alarm or dread.

3. Regarding an object or event; the state of fearing (something); apprehension or dread of something that will or may happen in the future.