Encyclopedia of Evolutionary Psychological Science

Living Edition
| Editors: Todd K. Shackelford, Viviana A. Weekes-Shackelford

Fear Affords Protection

  • Vincent BarnettEmail author
Living reference work entry
DOI: https://doi.org/10.1007/978-3-319-16999-6_2990-1


“Fear affords protection” refers to the evolutionary function of fear as an emotion, which is at root a form of protection or an early warning system against potentially serious threats. Fear itself has been defined as the “usually unpleasant feeling that arises as a normal response to realistic danger” (Marks 1987, 5). As was explained as early as 1704: “Fear … is a disturbance of mind proceeding from an apprehension of an approaching evil, threatening destruction or very great trouble either to us or ours” (Dennis 2000 [1704], 101). In its safe, narrative-generated form (e.g., in terror fiction such as horror novels or films), fear – and the adrenaline rush often associated with it – can become addictive (McCarty 1994, viii). This is because “beside lust and anger … [fear is] one of the three most exciting emotions of which our nature is susceptible” (James 1891, 2: 415).

As a very strong emotion, fear serves to alert an animal to any potential dangers, such as from a variety of attacking predators or any looming environmental dangers (e.g., cliff edges or jagged rocks), so as to effectively prepare for rapid action and/or to undertake the required behavior in order to have a better chance of remaining safe (Barrett 2005; Scalise Sugiyama 2006). For example, fear enables various animal response behaviors such as: quickly escaping by the safest route, defense upon imminent attack, freezing if this might assist in predator avoidance, or submitting to an attacker if this may yield a better chance of survival, for example, in intraspecies conflicts (Buss 2004, 91). The protective response of humans freezing in response to the fear generated by an individual suddenly glimpsing “the merciless teeth of Wolves” was noted as far back as the seventeenth century (Brown 1672, 134).

Fear also produces specific physiological and chemical responses, such as epinephrine being released, the heart rate speeding up or slowing down, and increased blood flow to the muscles, all of which assist in the fighting or fleeing behaviors that may be needed in order to survive the approaching danger. As an emotion, fear topped a recent psychologists’ chart of the top ten basic emotions (Parkinson 1994, 488).

Darwin on Fear

Pioneering scientific work on understanding the nature of fear as an emotion, and some associated predatory behaviors, was undertaken by Charles Darwin. For example, he was particularly interested in “monstrous” or carnivorous plants and conducted his own experiments on how these carnivorous plants absorbed different types of animal flesh as forms of captured prey (Darwin 1875). He also took a stuffed snake to a monkey house in order to test the fear responses of different types of monkey (Darwin 1874 [1871], 72). Darwin was interested in fear as an emotion as part of his wider evolutionary approach to understanding animal behavior.

In The Descent of Man, he explained that terror as an emotion caused “the muscles to tremble, the heart to palpitate, the sphincters to be relaxed, and the hair to stand on end” (Darwin 1874 [1871], 69). Although such associations are now sometimes seen as literary clichés, this does not mean that they are entirely inaccurate from a physiological perspective. The physiological changes that are now known to be affected by fear include: blood leaving the digestive tract and rushing to the periphery of the body; the adrenalin level spikes; the heart rate changes, either upwards for fleeing or downwards for freezing; and instruction to various parts of the musculature are sent (Tooby and Cosmides 2005, 54).

In The Expression of the Emotions in Animals and Man, Darwin provided a more detailed account: horror was accompanied by the body turning away, or the arms being violently protruded, or the raising of the shoulders, and a shudder and a deep expiration or inspiration (Darwin 1999 [1872], 308). He accounted for the biological function of the physiological reflexes associated with fear and horror as follows:

Some of the signs may be accounted for through the principles of habit, association, and inheritance – such as the wide opening of the mouth and eyes, with upraised eyebrows, so as to see as quickly as possible all around us, and to hear distinctly whatever sound may reach our ears. For we have thus habitually prepared ourselves to discover and encounter any danger … Men, during numberless generations, have endeavoured to escape from their enemies or danger by headlong flight, or by violently struggling with them; and such great exertions will have caused the heart to beat rapidly, the breathing to be hurried, the chest to heave … And now, whenever the emotion of fear is strongly felt, though it may not lead to any exertion, the same results tend to reappear (Ibid., 308–309).

The underlying principle that was expressed in this paragraph is still valid: the emotions of terror and horror have evolved in direct response to the threats to human life that were represented by animal predators and other human competitors.

Sometime later, in “A Biographical Sketch of an Infant,” he reported that: “Fear. – This feeling probably is one of the earliest which is experienced by infants,” as was demonstrated by young children exhibiting startled reactions to any sudden sounds from a very early age, from when they were only a few weeks old (Darwin 1977 [1877], 194). For Darwin, this clearly demonstrated that the fears of young children were independent of learning/experience, and instead were actually instinctual responses to common dangers encountered during the environment of evolutionary adaptedness, or what he called “ancient savage times” (Ibid., 195).

Darwin’s approach to defining the emotions of fear was rather sophisticated, distinguishing between horror and terror/extreme fear by arguing that although horror included terror and was almost synonymous with it, there was an anticipatory and sympathetic element involved with horror that was not present in terror. Terror was thus his term for a fearful emotion that was experienced directly by an individual, whereas horror was the appropriate term for when such terror was either anticipated for oneself, or sympathized with in the case of others (Darwin 1999 [1872], 306).

Darwin’s work on fear was part of his much larger project to understand the evolution of animal instincts, the development of which in its current manifestation is contemporary evolutionary psychology. A much more sophisticated account of the evolutionary basis of fear is consequently now available in the literature on this topic.

Fear as an Evolved Emotional System

Fear has been identified by contemporary neuroscientists as one of the four core premammalian emotional systems, as it is present in all vertebrates (Panksepp 2007, 146). As has been explained, the fear system in animals is “designed to detect danger and produce responses that maximize the probability of surviving” such danger (Campbell 2007, 368). This fear module has various different behavioral, physiological and verbal-cognitive components, and different animals react to the activation of their own specific fear system differently. For example:

Faced by a dog, a cat will bristle its fur. Because it is frightened, it becomes frightening. A butterfly of the Brazilian forests, the caligo defends itself by changing itself into the shape of a head of a bird of prey. It arches its body into the shape of a beak, and opens its wings which bear the image of an eye … and thus manages to give such a perfect imitation of an owl … (Volta 1965, 73).

Horses often respond to fear by bolting (Romanes 1898 [1878], 329). Fear programming and the fear response in animals thus varies by species and also by individual predator.

Moreover, the fear module is “organized around the amygdala, a limbic structure in the medial anterior temporal lobe … Its sharing among mammals and its subcortical location suggest that it has an ancient evolutionary origin” (Ohman and Mineka 2001, 486). To be more precise, it is the central nucleus of the amygdala that is primarily involved in the fear response (Carlson 2011, 278). As has been explained in this regard:

The location of the amygdala gives us a clue to the precise nature of its role in processing fear. It has connections to the autonomic nervous system … as well as to other brain regions that process sensory input. It’s like a neurological crossroads, the hub of a network of pathways in the brain, a special “rapid response unit,” if you like, primed to act quickly when presented with danger (Winston 2002, 49).

The fact that the amygdala acts so quickly when the fear module is activated indicates clearly that fear is an instinctual response, not a conscious or controllable one. Confirmation that the amygdala is involved in evaluating potential dangers, such as whether to trust unknown individuals or not, is available from people with damage to this region of the brain, who exhibited (on average) greater attribution of trustworthiness to strangers than a control group with no such brain injury (Patel et al. 2007, 50).

As has been outlined, the fear system has four basic characteristic features: (1) it is stimulus-specific, being activated by particular animals or situations, e.g., snakes or the danger of falling debris; (2) it is automatically and immediately stimulated by the relevant situations; (3) as already indicated, it is not under conscious control; (4) it has specific neural circuitry associated with it (Ohman and Mineka 2001).

Regarding the first characteristic, two key factors assist in tailoring fear reactions to specific stimuli. Prepotency is the fact that certain stimuli take the attention and cause more significant reactions in individuals than others, e.g., snakes and spiders cause much stronger fearful reactions in human beings than flies or birds. Preparedness is the fact that specific responses are tailored to specific stimuli, e.g., human beings exhibit a fearful reaction to snakes but a nauseated reaction to rotting food (Rossano 2003, 170–172).

The fact that this type of fear reaction is instinctive and generated by psychological mechanisms that have evolved in relation to the most common dangers found in the environment of evolutionary adaptedness is indicated by the fact that most human beings still exhibit a fear of snakes and spiders, which are in many contemporary urban environments only a very small danger, but exhibit no fear whatsoever of cigarettes and alcohol, two of the biggest killers of contemporary human beings across the globe.

Not only are specific fears tailored to specific stimuli, the developmental appearance of different fears in the human child progresses according to a well-designed pattern:

The emergence of certain fears, such as fear of strangers (stranger anxiety), fear of separation from a caregiver (separation anxiety), fear of heights, and fear of collision, all show consistent patterns based on the physical maturation of the infant … For example, the first evidence of stranger anxiety can be found in 4-5-months-olds in the form of a delayed negative reaction to the prolonged presence of a strange face (Rossano 2003, 173).

In addition, there is also an important place for environmental interaction/influence in the developmental appearance of fear, or what is termed social referencing, with infants responding to their own unique environmental experiences by showing modified expressions of particular fears, as is appropriate to their own particular environments.

Finally, it has been observed that not only do prey experience intense fear when they are under direct attack from predators, but some predators also experience some degree of fear when attempting to capture some types of prey. For example, when very powerful prey animals are being attacked, which usually occurs only in exceptional circumstances, the attacking predator animal also experiences fear, as they themselves are in some degree of danger too (Curio 1976, 123). As William James noted, “Fear is a reaction aroused by the same objects that arouse ferocity … We both fear, and wish to kill, anything that may kill us” (James 1891, 2: 415).

Sex Differences in Fear Behavior

There is a general consensus in the literature that there is a degree of difference in how males and females behave with respect to fear, with women (on average over large numbers of individuals) generally experiencing fear somewhat more intensely, more frequently, and for longer durations than men (Campbell 2007, 368), although this is true in relative terms only. Men can still experience very intense fear, given the right circumstances of danger, just as women can. It is probably accurate to state that men and women can experience the same overall range of fear, but that the fear system in men appears to be (on average) set at a little less sensitively than the fear system in women.

This sex difference in fear response is partly confirmed by the fact that, physiologically, it has been reported that women exhibit higher rises in skin conductance and a heightened startle reflex in reaction to scenes of danger compared to men, and that women tend to exhibit greater degrees of phobic fear (Campbell 2007, 369). It has been suggested that this sex difference in fear sensitivity is linked to the fact that males tend to take more risks in general terms than females, for example, in relation to engaging in physical altercations with other members of the same sex. Males also tend to take more risks (on average) compared to females in relation to their degree of involvement in other physically risky activities, e.g., extreme sports participation and vehicular driving styles.

Malfunctions of The Fear System

The fear system in human beings, however, has some significant in-built flaws that can have important consequences for understanding aspects of contemporary human behavior. For example:

Because self-protection is imperative from an evolutionary perspective, the mind is designed to be hyper-sensitive to threats, even if such threats are ambiguous or hypothetical, similar to how a sensitive smoke detector detects and acts upon the tiniest bit of evidence indicating potential danger at the cost of occasional false alarms (Griskevicius et al. 2012, 315).

The logic at work here is that it is better to set the activation of the protective fear system threat level very low, even with the potential for many false alarms, rather than to fix it at too high a setting, the latter enabling the potential for some genuine threats to go unnoticed.

However, this may mean that some human beings are potentially liable to certain afflictions/malfunctions of the fear system, such as anxiety attacks, vertigo, and various different phobias (e.g., arachnophobia, agoraphobia, claustrophobia), which, instead of assisting the individual to function well, may actually hinder their normal operation in certain very specific circumstances (Marks and Nesse 1994). From an evolutionary perspective, potential malfunctions of the fear system are unavoidable costs that have to be borne, given the overall positive benefit that this system generates for human survival prospects in assorted dangerous environments.

Fear and Intergroup Prejudice

It has been suggested that certain types of intergroup prejudice can be traced to the existence of coalitional psychology as it evolved in relation to the tribal prehistory of human beings, to associated intertribal conflicts, and to the evolution of in-group out-group fears that were based on the existence of various outsider threats (Park 2012, 188; Kurzban and Neuberg 2005, 667). The related concepts of inclusive fitness and ethnic kinship further suggest that ethnic-nepotism was, in evolutionary times, sometimes a form of adaptive behavior, as it served a useful protective function (Salter 2007, 541).

Tribal conflicts and intergroup hostilities were, therefore, an unavoidable part of human prehistory, and it seems likely that specific psychological mechanisms evolved to deal with these realities. These hypotheses lead to the conclusion that fear, as an evolved emotional system of protection against outsider threats, might be at the root of at least some of the contemporary manifestations of intergroup prejudice. Correctly recognizing the evolutionary roots of this type of fear, therefore, has the potential for better understanding the nature of intergroup prejudice and, in turn, devising better/more effective methods of dealing with it.

Critics of evolutionary psychology may argue that, by positing the existence of this evolutionary basis for in-group out-group prejudice and also for ethnic nepotism, the results can be the justification of such prejudice. These critics need to understand that, if the framework of evolutionary psychology is correct, then ignoring or denying the reality of evolved human nature will not assist in overcoming prejudice. It is much more effective to work alongside human nature in order to solve contemporary problems rather than to work against it or to deny that human nature exists at all.

Fear in Art and Literature

Although of very ancient animal origin, fear is still very much a contemporary emotional reality, one indication of this being the ongoing popularity of the horror genre in film and literature across the world (Barnett 2018). If fictive fears in the horror genre experienced indirectly – through art and literature – are seen to reflect the terrors of dangerous splits in the social realm, then real-life fears experienced directly can be seen to reflect the terrors of dangerous splits in the natural world, primarily that between predator and prey (Moretti 2005 [1978], 83; Scalise Sugiyama 2006). These two worlds of art and nature sometimes overlap, providing a further enabling of the protective function of fear.

Consider the example of the werewolf, the mythology of which is “anciently and universally diffused” across Europe and elsewhere, going back at least as far as the thirteenth century (Summers 1934, 20). For Darwin, the transformative power of wolves was not an entirely fictitious quality; he noted reports that a few wolves varied the color-shading on their fur in order to match seasonal changes in the environment (Darwin 1874 [1871], 542). Some human tribes even wore wolf-skins as a symbolic attempt to harness their animalistic powers, and this practice of making hunting disguises from animal skins has been cited as the origin of the werewolf mythology (Langford 1997, 1006; Stewart 1909, 260).

The historian of occult mythology Montague Summers, known for his belief in the reality of supernatural creatures like vampires and werewolves, unknowingly described very clearly how natural predators like wolves readily assumed a larger-than-life quality in the ancestral human consciousness:

Throughout the ages, even in the prehistoric world, whilst his howling athwart the stillness of nature and night struck fear into the heart of primaeval man … further down the centuries when he was known as the savage plunderer and swift pitiless marauder of the shepherd’s grazing flocks, not sparing to attack child and maid or even the solitary wayfarer by the wood … all down the vistas of dateless centuries the wolf has ever been the inevitable, remorseless enemy of man … [part of] the experience and dearly purchased knowledge of our forefathers … (Summers 1934, 64–65).

Summers’ error was in taking the mythologized version of the wolf too literally, when what should have been taken literally, was the folk-narratives that have been used to warn of the real dangers of wolf attacks: “as the flesh-and-blood wolf continues to haunt the Transylvanian forests, so long will his spectre brother survive” (Gerard 1888, 187).

The link between superstitions expressed in nightmares and the “sudden transformation of one person into another or into some animal; the occurrence of phantastic and impossible animal forms” has previously been highlighted (Jones 1931, 238). This fearful link makes concrete the connection between primitive animal dangers and modern horror narratives that allude to the animal side of human nature and related transformative themes, which in reality are simply mediated embellishments on much older predator fears.


Beginning with Darwin’s pioneering work on understanding fear, evolutionary psychologists have more recently given the protective function of fear their full investigative attention, as it is a powerful and an important emotion that affects many different aspects of human behavior, most importantly, assisting the survival instincts. Consequently, instead of the false promise of the anemic adage “nothing to fear but fear itself,” the much more realistic maxim that animals live by is “nothing to fear but the many thousands of predators spread across the globe.” From a Darwinian perspective, fear is not a “mind killer” that has no real rational foundations, as has been argued elsewhere (Plamper and Lazier 2012), but instead is an essential “mind saver” that all animal life constantly relies upon for its ongoing survival.

However, various malfunctions of the fear system are also important to understand as they may be at the root of the prevalence of various contemporary panic and anxiety disorders. In addition, only by understanding the evolutionary origins of fear as an emotion, will any potentially negative side effects of it that are still being manifest today, such as intergroup prejudice, be able to be effectively mitigated. Finally, it should be stressed that human beings should not be frightened of expressions of fear but instead should celebrate and revel in them, as such frightful and terrific expressions of emotion have undoubtedly contributed to saving countless human and animal lives across the vast evolutionary past.



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© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Independent ScholarLondonUK

Section editors and affiliations

  • Kevin Bennett
    • 1
  1. 1.Department of PsychologyPennsylvania State University, BeaverMonacaUSA