Fear Factory Members

Fear is an intensely unpleasant emotion in response to perceiving or recognizing a danger or threat. Fear causes physiological changes that may produce behavioral reactions such as mounting an aggressive response or fleeing the threat. Fear in human beings may occur in response to a certain stimulus occurring in the present, or in anticipation or expectation of a future threat perceived as a risk to oneself. The fear response arises from the perception of danger leading to confrontation with or escape from/avoiding the threat (also known as the fight-or-flight response), which in extreme cases of fear (horror and terror) can be a freeze response or paralysis.

In humans and other animals, fear is modulated by the process of cognition and learning. Thus, fear is judged as rational or appropriate and irrational or inappropriate. An irrational fear is called a phobia.

Fear is closely related to the emotion anxiety, which occurs as the result of threats that are perceived to be uncontrollable or unavoidable. The fear response serves survival by engendering appropriate behavioral responses, so it has been preserved throughout evolution. Sociological and organizational research also suggests that individuals' fears are not solely dependent on their nature but are also shaped by their social relations and culture, which guide their understanding of when and how much fear to feel.

Fear is sometimes incorrectly considered the opposite of courage. Because courage is a willingness to face adversity, fear is an example of a condition that makes the exercise of courage possible.

Physiological signs

Many physiological changes in the body are associated with fear, summarized as the fight-or-flight response. An innate response for coping with danger, it works by accelerating the breathing rate (hyperventilation), heart rate, vasoconstriction of the peripheral blood vessels leading to blood pooling, increasing muscle tension including the muscles attached to each hair follicle to contract and causing "goosebumps", or more clinically, piloerection (making a cold person warmer or a frightened animal look more impressive), sweating, increased blood glucose (hyperglycemia), increased serum calcium, increase in white blood cells called neutrophilic leukocytes, alertness leading to sleep disturbance and "butterflies in the stomach" (dyspepsia). This primitive mechanism may help an organism survive by either running away or fighting the danger. With the series of physiological changes, the consciousness realizes an emotion of fear.

Causes

An influential categorization of stimuli causing fear was proposed by Gray; namely, intensity, novelty, special evolutionary dangers, stimuli arising during social interaction, and conditioned stimuli. Another categorization was proposed by Archer, who, besides conditioned fear stimuli, categorized fear-evoking (as well as aggression-evoking) stimuli into three groups; namely, pain, novelty, and frustration, although he also described “looming,” which refers to an object rapidly moving towards the visual sensors of a subject, and can be categorized as “intensity.” Russell described a more functional categorization of fear-evoking stimuli, in which for instance novelty is a variable affecting more than one category: 1) Predator stimuli (including movement, suddenness, proximity, but also learned and innate predator stimuli); 2) Physical environmental dangers (including intensity and heights); 3) Stimuli associated with increased risk of predation and other dangers (including novelty, openness, illumination, and being alone); 4) Stimuli stemming from conspecifics (including novelty, movement, and spacing behavior); 5) Species-predictable fear stimuli and experience (special evolutionary dangers); and 6) Fear stimuli that are not species predictable (conditioned fear stimuli).

Nature

Although many fears are learned, the capacity to fear is part of human nature. Many studies have found that certain fears (e.g. animals, heights) are much more common than others (e.g. flowers, clouds). These fears are also easier to induce in the laboratory. This phenomenon is known as preparedness. Because early humans that were quick to fear dangerous situations were more likely to survive and reproduce; preparedness is theorized to be a genetic effect that is the result of natural selection.

From an evolutionary psychology perspective, different fears may be different adaptations that have been useful in our evolutionary past. They may have developed during different time periods. Some fears, such as fear of heights, may be common to all mammals and developed during the mesozoic period. Other fears, such as fear of snakes, may be common to all simians and developed during the cenozoic time period (the still-ongoing geological era encompassing the last 66 million of history). Still others, such as fear of mice and insects, may be unique to humans and developed during the paleolithic and neolithic time periods (when mice and insects become important carriers of infectious diseases and harmful for crops and stored foods).

Conditioning

Nonhuman animals and humans innovate specific fears as a result of learning. This has been studied in psychology as fear conditioning, beginning with John B. Watson's Little Albert experiment in 1920, which was inspired after observing a child with an irrational fear of dogs. In this study, an 11-month-old boy was conditioned to fear a white rat in the laboratory. The fear became generalized to include other white, furry objects, such as a rabbit, dog, and even a Santa Claus mask with white cotton balls in the beard.

Fear can be learned by experiencing or watching a frightening traumatic accident. For example, if a child falls into a well and struggles to get out, he or she may develop a fear of wells, heights (acrophobia), enclosed spaces (claustrophobia), or water (aquaphobia). There are studies looking at areas of the brain that are affected in relation to fear. When looking at these areas (such as the amygdala), it was proposed that a person learns to fear regardless of whether they themselves have experienced trauma, or if they have observed the fear in others. In a study completed by Andreas Olsson, Katherine I. Nearing and Elizabeth A. Phelps, the amygdala were affected both when subjects observed someone else being submitted to an aversive event, knowing that the same treatment awaited themselves, and when subjects were subsequently placed in a fear-provoking situation. This suggests that fear can develop in both conditions, not just simply from personal history.

Fear is affected by cultural and historical context. For example, in the early 20th century, many Americans feared polio, a disease that can lead to paralysis. There are consistent cross-cultural differences in how people respond to fear. Display rules affect how likely people are to express the facial expression of fear and other emotions.

Fear of victimization is a function of perceived risk and seriousness.

Common triggers

Phobias

According to surveys, some of the most common fears are of demons and ghosts, the existence of evil powers, cockroaches, spiders, snakes, heights, water, enclosed spaces, tunnels, bridges, needles, social rejection, failure, examinations, and public speaking.

Uncertainty

Fear of the unknown or irrational fear is caused by negative thinking (worry) which arises from anxiety accompanied by a subjective sense of apprehension or dread. Irrational fear shares a common neural pathway with other fears, a pathway that engages the nervous system to mobilize bodily resources in the face of danger or threat. Many people are scared of the "unknown". The irrational fear can branch out to many areas such as the hereafter, the next ten years or even tomorrow. Chronic irrational fear has deleterious effects since the elicitor stimulus is commonly absent or perceived from delusions. Such fear can create comorbidity with the anxiety disorder umbrella. Being scared may cause people to experience anticipatory fear of what may lie ahead rather than planning and evaluating for the same. For example, "continuation of scholarly education" is perceived by many educators as a risk that may cause them fear and stress, and they would rather teach things they've been taught than go and do research.

The ambiguity of situations that tend to be uncertain and unpredictable can cause anxiety in addition to other psychological and physical problems in some populations; especially those who engage it constantly, for example, in war-ridden places or in places of conflict, terrorism, abuse, etc. Poor parenting that instills fear can also debilitate a child's psyche development or personality. For example, parents tell their children not to talk to strangers in order to protect them. In school, they would be motivated to not show fear in talking with strangers, but to be assertive and also aware of the risks and the environment in which it takes place. Ambiguous and mixed messages like this can affect their self-esteem and self-confidence. Researchers say talking to strangers isn't something to be thwarted but allowed in a parent's presence if required. Developing a sense of equanimity to handle various situations is often advocated as an antidote to irrational fear and as an essential skill by a number of ancient philosophies.

Fear of the unknown (FOTU) "may be a, or possibly the, fundamental fear" from early times when there were many threats to life.

American top tens

In a 2005 Gallup Poll (U.S.), a national sample of about 1000 adolescents (aged 13 to 17) were asked what they feared the most as an open-ended question. The American adolescents reported perceiving their top ten fears as follows: terrorist attacks, spiders, death, failure, war, criminal or gang violence, being alone, the future, and nuclear war.

In an estimate of what Americans fear the most, book author Bill Tancer analyzed the most frequent online queries that involved the phrase, "fear of..." following the assumption that people tend to seek information on the issues that concern them the most. His top ten list of fears published 2008 consisted of flying, heights, clowns, intimacy, death, rejection, people, snakes, failure, and driving.

Behavior

Although fear behavior varies from species to species, it is often divided into two main categories; namely, avoidance/flight and immobility. To these, different researchers have added different categories, such as threat display and attack, protective responses (including startle and looming responses), defensive burying, and social responses (including alarm vocalizations and submission). Finally, immobility is often divided into freezing and tonic immobility.

The decision as to which particular fear behavior to perform is determined by the level of fear as well as the specific context, such as environmental characteristics (escape route present, distance to refuge), the presence of a discrete and localized threat, the distance between threat and subject, threat characteristics (speed, size, directness of approach), the characteristics of the subject under threat (size, physical condition, speed, degree of crypsis, protective morphological structures), social conditions (group size), and the amount of experience with the type of the threat.

Mechanism

Often laboratory studies with rats are conducted to examine the acquisition and extinction of conditioned fear responses. In 2004, researchers conditioned rats (''Rattus norvegicus'') to fear a certain stimulus, through electric shock. The researchers were able to then cause an extinction of this conditioned fear, to a point that no medications or drugs were able to further aid in the extinction process. The rats showed signs of avoidance learning, not fear, but simply avoiding the area that brought pain to the test rats. The avoidance learning of rats is seen as a conditioned response, and therefore the behavior can be unconditioned, as supported by the earlier research.

Species-specific defense reactions (SSDRs) or avoidance learning in nature is the specific tendency to avoid certain threats or stimuli, it is how animals survive in the wild. Humans and animals both share these species-specific defense reactions, such as the flight-or-fight, which also include pseudo-aggression, fake or intimidating aggression and freeze response to threats, which is controlled by the sympathetic nervous system. These SSDRs are learned very quickly through social interactions between others of the same species, other species, and interaction with the environment. These acquired sets of reactions or responses are not easily forgotten. The animal that survives is the animal that already knows what to fear and how to avoid this threat. An example in humans is the reaction to the sight of a snake, many jump backwards before cognitively realizing what they are jumping away from, and in some cases, it is a stick rather than a snake.

As with many functions of the brain, there are various regions of the brain involved in deciphering fear in humans and other nonhuman species. The amygdala communicates both directions between the prefrontal cortex, hypothalamus, the sensory cortex, the hippocampus, thalamus, septum, and the brainstem. The amygdala plays an important role in SSDR, such as the ventral amygdalofugal, which is essential for associative learning, and SSDRs are learned through interaction with the environment and others of the same species. An emotional response is created only after the signals have been relayed between the different regions of the brain, and activating the sympathetic nervous systems; which controls the flight, fight, freeze, fright, and faint response. Often a damaged amygdala can cause impairment in the recognition of fear (like the human case of patient S.M.). This impairment can cause different species to lack the sensation of fear, and often can become overly confident, confronting larger peers, or walking up to predatory creatures.

Robert C. Bolles (1970), a researcher at University of Washington, wanted to understand species-specific defense reactions and avoidance learning among animals, but found that the theories of avoidance learning and the tools that were used to measure this tendency were out of touch with the natural world. He theorized the species-specific defense reaction (SSDR). There are three forms of SSDRs: flight, fight (pseudo-aggression), or freeze. Even domesticated animals have SSDRs, and in those moments it is seen that animals revert to atavistic standards and become "wild" again. Dr. Bolles states that responses are often dependent on the reinforcement of a safety signal, and not the aversive conditioned stimuli. This safety signal can be a source of feedback or even stimulus change. Intrinsic feedback or information coming from within, muscle twitches, increased heart rate, are seen to be more important in SSDRs than extrinsic feedback, stimuli that comes from the external environment. Dr. Bolles found that most creatures have some intrinsic set of fears, to help assure survival of the species. Rats will run away from any shocking event, and pigeons will flap their wings harder when threatened. The wing flapping in pigeons and the scattered running of rats are considered species-specific defense reactions or behaviors. Bolles believed that SSDRs are conditioned through Pavlovian conditioning, and not operant conditioning; SSDRs arise from the association between the environmental stimuli and adverse events. Michael S. Fanselow conducted an experiment, to test some specific defense reactions, he observed that rats in two different shock situations responded differently, based on instinct or defensive topography, rather than contextual information.

Species-specific defense responses are created out of fear, and are essential for survival. Rats that lack the gene stathmin show no avoidance learning, or a lack of fear, and will often walk directly up to cats and be eaten. Animals use these SSDRs to continue living, to help increase their chance of fitness, by surviving long enough to procreate. Humans and animals alike have created fear to know what should be avoided, and this fear can be learned through association with others in the community, or learned through personal experience with a creature, species, or situations that should be avoided. SSDRs are an evolutionary adaptation that has been seen in many species throughout the world including rats, chimpanzees, prairie dogs, and even humans, an adaptation created to help individual creatures survive in a hostile world.

Fear learning changes across the lifetime due to natural developmental changes in the brain. This includes changes in the prefrontal cortex and the amygdala.

The visual exploration of an emotional face does not follow a fixed pattern but modulated by the emotional content of the face. Scheller et al. found that participants paid more attention to the eyes when recognising fearful or neutral faces, while the mouth was fixated on when happy faces are presented, irrespective of task demands and spatial locations of face stimuli. These findings were replicated when fearful eyes are presented and when canonical face configurations are distorted for fearful, neutral and happy expressions.

Neurocircuitry in mammals

* The thalamus collects sensory data from the senses
* Sensory cortex receives data from the thalamus and interprets it
* Sensory cortex organizes information for dissemination to the hypothalamus (fight or flight), amygdalae (fear), hippocampus (memory)

The brain structures that are the center of most neurobiological events associated with fear are the two amygdalae, located behind the pituitary gland. Each amygdala is part of a circuitry of fear learning. They are essential for proper adaptation to stress and specific modulation of emotional learning memory. In the presence of a threatening stimulus, the amygdalae generate the secretion of hormones that influence fear and aggression. Once a response to the stimulus in the form of fear or aggression commences, the amygdalae may elicit the release of hormones into the body to put the person into a state of alertness, in which they are ready to move, run, fight, etc. This defensive response is generally referred to in physiology as the fight-or-flight response regulated by the hypothalamus, part of the limbic system. Once the person is in safe mode, meaning that there are no longer any potential threats surrounding them, the amygdalae will send this information to the medial prefrontal cortex (mPFC) where it is stored for similar future situations, which is known as memory consolidation.

Some of the hormones involved during the state of fight-or-flight include epinephrine, which regulates heart rate and metabolism as well as dilating blood vessels and air passages, norepinephrine increasing heart rate, blood flow to skeletal muscles and the release of glucose from energy stores, and cortisol which increases blood sugar, increases circulating neutrophilic leukocytes, calcium amongst other things.

After a situation which incites fear occurs, the amygdalae and hippocampus record the event through synaptic plasticity. The stimulation to the hippocampus will cause the individual to remember many details surrounding the situation. Plasticity and memory formation in the amygdala are generated by activation of the neurons in the region. Experimental data supports the notion that synaptic plasticity of the neurons leading to the lateral amygdalae occurs with fear conditioning. In some cases, this forms permanent fear responses such as posttraumatic stress disorder (PTSD) or a phobia. MRI and fMRI scans have shown that the amygdalae in individuals diagnosed with such disorders including bipolar or panic disorder are larger and wired for a higher level of fear.

Pathogens can suppress amygdala activity. Rats infected with the toxoplasmosis parasite become less fearful of cats, sometimes even seeking out their urine-marked areas. This behavior often leads to them being eaten by cats. The parasite then reproduces within the body of the cat. There is evidence that the parasite concentrates itself in the amygdala of infected rats. In a separate experiment, rats with lesions in the amygdala did not express fear or anxiety towards unwanted stimuli. These rats pulled on levers supplying food that sometimes sent out electrical shocks. While they learned to avoid pressing on them, they did not distance themselves from these shock-inducing levers.

Several brain structures other than the amygdalae have also been observed to be activated when individuals are presented with fearful vs. neutral faces, namely the occipitocerebellar regions including the fusiform gyrus and the inferior parietal / superior temporal gyri. Fearful eyes, brows and mouth seem to separately reproduce these brain responses. Scientists from Zurich studies show that the hormone oxytocin related to stress and sex reduces activity in your brain fear center.

Pheromones and contagion

In threatening situations, insects, aquatic organisms, birds, reptiles, and mammals emit odorant substances, initially called alarm substances, which are chemical signals now called alarm pheromones. This is to defend themselves and at the same time to inform members of the same species of danger and leads to observable behavior change like freezing, defensive behavior, or dispersion depending on circumstances and species. For example, stressed rats release odorant cues that cause other rats to move away from the source of the signal.

After the discovery of pheromones in 1959, alarm pheromones were first described in 1968 in ants and earthworms, and four years later also found in mammals, both mice and rats. Over the next two decades, identification and characterization of these pheromones proceeded in all manner of insects and sea animals, including fish, but it was not until 1990 that more insight into mammalian alarm pheromones was gleaned.

In 1985, a link between odors released by stressed rats and pain perception was discovered: unstressed rats exposed to these odors developed opioid-mediated analgesia. In 1997, researchers found that bees became less responsive to pain after they had been stimulated with isoamyl acetate, a chemical smelling of banana, and a component of bee alarm pheromone. The experiment also showed that the bees' fear-induced pain tolerance

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