Universal Human Fears
University of Trnava, Trnava, Slovakia
A distressing emotion caused by anticipation or
awareness of danger.
Darwin states, in his book The Expression of the
Emotions in Man and Animals which supported
the theory of natural selection, that fear is “the
most depressing of all the emotions”(Darwin
1872, p. 36). A century later, basic emotion theo-
rists have proposed that certain emotions are
innate, in part because they are expressed the
same in people around the world (e.g., Ekman
1977). There is growing agreement among
researchers that fear is an adaptive emotion that
motivates “ﬁght or ﬂy”behavior, ultimately pro-
moting self-protection. This entry is focused on
(1) domains of human fear and (2) preparedness
learning, (3) perceptual biases, and (4) gender
differences to support its evolutionary origin.
Fear is associated with ancient parts of the
brain; the amygdala areas, which are located
deep and medially within the temporal lobes of
the brain, have been involved in fear conditioning
in a variety of mammals, including rats, mice,
rabbits, and monkeys (for a review, see LeDoux
2012). Almost universal physiological and behav-
ioral responses to fear-related stimuli are escape,
avoidance behavior, a stronger heart rate, blood
pressure, respiration, and adrenaline and gluco-
corticoid release. It is suggested that fear-related
responses are adaptive, because they prepare our
bodies for a ﬁght or escape from a potential dan-
ger. Both types of responses require accelerated
metabolism via glucose release by adrenaline and
oxygen supply to the muscles by rapid breathing
in order to make energy available to the muscles
for ﬁght or ﬂight (Marks and Nesse 1994).
Evolutionary psychologists have suggested
that fear has developed for mostly ancient threats
(e.g., certain animals such as snakes, spiders and
rats, heights, storms, darkness, blood, strangers,
and separation or leaving the safety of home), but
not to current threats (e.g., cigarettes, cars, elec-
trical equipment, or handguns). Three lines of
evidence support this idea. First, fear stimuli are
nonrandomly distributed and are related to real
(albeit ancient) threats (Marks and Nesse 1994).
People rarely display, for example, a fear of trees,
stones, or the sky which were not harmful to our
ancestors, but fears of harmful objects or events
#Springer International Publishing Switzerland 2016
T.K. Shackelford, V.A. Weekes-Shackelford (eds.), Encyclopedia of Evolutionary Psychological Science,
are relatively common. Second, Martin Seligman
(1971) has proposed that fears reﬂect evolution-
arily prepared learning to fear events and situa-
tions that have provided survival threats in our
evolutionary past. This can be documented with
classic experiments carried out by Cook and
Mineka (1990,1991). Laboratory-reared, but not
wild, monkeys do not manifest strong fearful
responses to snakes suggesting that their reactions
are learned, rather than innate. Monkeys are, how-
ever, able to quickly acquire a fear of a predator by
observing other monkeys expressing fear in inter-
action with the predator. When laboratory-reared
monkeys observed a wild-reared monkey
displaying fear of a live and toy snake, they were
rapidly conditioned to fear snakes (Cook and
Mineka 1990). In consequent experiments, the
laboratory-reared monkeys observed displays of
fear in response to toy snakes (predators) and
ﬂowers (harmless objects) or to toy crocodiles
(predators) and rabbits (harmless objects). Fear
responses were conditioned only for predators,
but not for ﬂowers and toy rabbits (Cook and
Mineka 1991). Since the laboratory-reared mon-
keys had no previous experiences with the stimuli
used in the experiment, these results provide sup-
port for an evolutionary basis to the prepared
learning (Öhman and Mineka 2001).
Third, common human fears seem to develop
at a time when the danger might be encountered.
Fears of heights and strangers, for example,
emerge in infants at about 6 months of age,
when infants begin to crawl away from their
mothers thereby increasing the risk of a fall
and/or kidnapping. The higher risk of an infant
being killed by strangers has been documented
both in nonhuman primates as well as in modern
humans. At the age of 2 years, when infant explo-
ration begins to be more intense, animal fears and
fear of darkness emerge (for a review, see Gullone
2000). Humans, unlike nocturnal animals, have
limited vision making them more vulnerable to
predators when their visual capacity is limited.
Fear of the dark restricts infant mobility thereby
decreasing vulnerability to predators. Later, when
the young child leaves the home base, agorapho-
bia, the fear of being in crowds or public places,
which makes escape difﬁcult, may develop
(Marks and Nesse 1994). The intensity of fears
in children tend to decrease with age (Gullone
2000) which can be explained by their higher
physical and emotional independence from
Evolutionary Evidence for Fear
of Dangerous Animals
Snakes are viewed as prototypical stimuli of com-
mon fears of animals (Öhman and Mineka 2001).
Snakes are present on all continents except Ant-
arctica, and their putative fossils date back as far
as 150 million years. At this time, constrictor
snakes were critical predators of the small ances-
tors of modern placental mammals (Isbell 2009).
Note that carnivore predators occurred much later,
only about 40–60 million years ago. Transitional
primate-like creatures were evolving ca. 65.5 mil-
lion years ago, and recent primates are still
attacked by snakes (Cook and Mineka 1991).
This evidence suggests that the evolution of pri-
mate defense against predators was inﬂuenced by
The second line of evidence regarding danger
from snakes comes from introducing an effective
venom –a new powerful weapon in the
predator–prey arms race with primates. Fossils
of snakes with venomous fangs from at least the
Lower Miocene have been discovered, i.e., far
before the ﬁrst ancestors of Homo appeared.
This evidence strongly suggests that interactions
between snakes and early humans could be
expected. Snake bite caused substantial human
mortality and disability, although these issues
have been largely neglected by health organiza-
tions. It is estimated that snake bites cause roughly
about 20,000–125,000 deaths worldwide,
although these estimates are based on incomplete
data (Warrell 2010), partly because reporting is
not mandatory in many regions of the world. It can
be suggested that snake mortality was much
higher in our evolutionary past, when human
interaction with nature occurred daily and medical
help was highly limited (if any).
The early coexistence of dangerous snakes
with their mammalian prey may be the reason
2 Universal Human Fears
why snakes are frequently sources of phobias.
Robins and Regier (1991), for example, deter-
mined that “bugs, mice, snakes or bats”were the
most frequently cited category of phobic fears.
Indeed, snakes are traditionally labeled as the
least liked animals in a range of surveys on animal
fears, while certain other terrestrial predators such
as wolves or bears received more positive rank-
ings by people (Schlegel and Rupf 2010; Almeida
et al. 2014).
Threatening Objects Promote Visual
Coevolution with snakes as signiﬁcant primate
predators predicts that primates, including
humans, should have developed a speciﬁc visual
sensitivity for snake (i.e., danger) cues that pro-
motes vigilance for an early detection of stimuli to
escape and/or avoid potentially a deadly encoun-
ter with the predator and hence survive and repro-
duce (Öhman et al. 2001a). Neurobiological
research supports this idea, because amygdala
tunes visual brain areas for rapid perception of
fear-related stimuli. Furthermore, it seems that
speciﬁc neurons in the primate brain respond
especially quickly to images of snakes (Van Le
et al. 2013). Humans, similarly to nonhuman pri-
mates, seem to have no innate fear of snakes
(DeLoache and LoBue 2009), but show similar
abilities to condition snakes with something fear-
ful (LoBue and DeLoache 2010). Rakison and
Derringer (2008) found, for example, that
5-month-old infants look longer at a schematic
image of a spider or a snake relative to scrambled
versions of the same schematic image and look
equally long at nonthreatening images such as
To support the rapid detection of snakes rela-
tive to other non-treating stimuli, Öhman
et al. (2001a) compared the detection of a fear-
relevant target (a snake or a spider) among eight
fear-irrelevant distractors (ﬂowers or mushrooms)
with that of a fear-irrelevant target (a ﬂower or a
mushroom) among fear-relevant distractors
(snakes or spiders). As expected, snakes and spi-
ders were detected more quickly than ﬂowers and
mushrooms. These ﬁndings were repeatedly
reported in a number of studies, involving both
children and adults (for a review, see LoBue and
Rakison 2013). It can be argued that humans
should also be sensitive to a visual detection of
the emotional cues in the faces of other members
in the social group because signiﬁcant numbers of
violent deaths can be attributed to conﬂicts
between conspeciﬁcs –similarly as with chimpan-
zees. The same paradigm suggesting that fear-
relevant stimuli receive rapid detection in order
to avoid potential threat, Öhman et al. (2001b)
found that threatening faces are detected by
humans among neutral faces more quickly than
friendly faces, a ﬁnding which was successfully
replicated by other researchers (for a review,
Öhman et al. 2001b; LoBue and Rakison 2013).
These ﬁndings suggest that there is a clear bias for
threat in visual detection tasks.
Gender Differences in Common Fears
Girls exhibit more fears than boys (Arrindell
et al. 2003), and at least some of them can emerge
very early (Rakison 2009). In particular, girls
reported being more fearful of darkness, strange
sights and sounds, loneliness, personal relation-
ships, animals, injury, and being kidnapped,
robbed, or killed (Gullone 2000; Arrindell
et al. 2003). Boys reported being more fearful of
not being good and getting into trouble, night-
mares, and imaginary creatures including mon-
sters, gorillas, and dinosaurs (for a review, see
Gullone 2000). Gender socialization experiences
may contribute to the reporting of fear difference
by males and females. Girls may learn that it is
permissible to express fears, whereas boys are
expected to inhibit fears. Rakison (2009) found,
however, that 11-month-old female but not male
infants learn rapidly to associate negative facial
emotions with fear-relevant stimuli (snakes and
spiders) suggesting that socialization need not to
be the key factor responsible for gender differ-
ences in fearfulness.
Although gender differences in fears were
reported in a number of studies, their evolutionary
origin is much less clear. Certain researchers have
Universal Human Fears 3
suggested that a higher fear of large carnivore
predators in females can be explained by female’s
lower physical condition compared with the phys-
ical condition of males (Røskaft et al. 2003;
Prokop and Fančovičová 2013). Indeed, females
and children who are physically weaker than
males are less likely to survive predatory attacks
of large carnivores (Treves and Naughton-Treves
1999). The disease avoidance hypothesis suggests
that vulnerability to infectious diseases makes
people more sensitive to a potential danger.
Indeed, females are more disease vulnerable than
males, and more disease-vulnerable people per-
ceive animals as more dangerous than less
disease-vulnerable people (Prokop and
Fančovičová 2013). These two hypotheses can
be viewed as compatible, because disease vulner-
ability is associated with a poorer perceived phys-
ical condition (Prokop and Fančovičová 2013).
The parental investment hypothesis proposes
that females take care of children and have to be
more sensitive to danger in order to protect their
offspring (Røskaft et al. 2003). This hypothesis
has not received empirical support as yet.
Why Humans Display a Fear of Harmless
About 100 years ago, John Watson demonstrated
that an infant (9-month-old Little Albert) can be
conditioned to fear a white rat by pairing the
presentation of the rat with a loud aversive noise.
Upon seeing the rat, Little Albert became
extremely distressed, crying and crawling away.
Interestingly, Little Albert’s fear was later gener-
alized to the sight of several other furry objects,
such as a rabbit, a furry dog, and a sealskin coat
and even a Santa Claus mask with white cotton
balls in the beard. It was later proposed of course
that classic conditioning is not the only way one
acquires fear. Observations, verbally transmitted
information, and some other mechanisms (LoBue
2013) can also develop fear.
This simple example of Little Albert’s gener-
alization of fear may explain why humans mani-
fest a fear of certain fear-irrelevant stimuli:
harmless snakes (Arrindell et al. 2003)or
wormlike invertebrates (Schlegel et al. 2015) are
considered dangerous or unlikeable, although
they do not pose an actual danger. All of these
stimuli are associated with potentially dangerous
cues, because they superﬁcially look like danger-
ous animals. The superﬁcial perception of poten-
tially harmful stimuli is favored by natural
selection in order to minimize the likelihood of
failing to register the presence of genuine danger
(the smoke detector principle, Nesse 2005).
Although the avoidance of harmless snake could
be perceived as “erroneous”(false-positive error),
it is still less risky than erroneous detection of a
truly harmful snake (false-negative error). That is,
predictions guided by the evolutionary theory do
not propose that all fears should have reasonable
explanations in our ancestral past, but that certain
fears can also stem from similarities with fear-
relevant stimuli. Finally, some fears are condi-
tioned in everyday life. Children can, for example,
easily acquire fear of a medical doctor simply
because pain from vaccination is associated with
the doctor. The same mechanism can be applied to
dogs showing a fear of veterinarians.
The protective emotion of fear was highly beneﬁ-
cial in the ancestral environment where it evolved.
Modern society, where the risk of being attacked
by a predator is low, may perceive certain fears as
irrational, but a better understanding of our evo-
lutionary past would seem to be helpful in
reaching an understanding of our emotions. Com-
parative research on nonhuman primates and
human infants where socialization is minimal
seems to be promising in uncovering the origins
and adaptive functions of common fears.
Acknowledgments I thank David Livingstone for
improving the English. This study was partly funded by
grant VEGA no. 1/0104/16.
4 Universal Human Fears
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Universal Human Fears 5