* Contemporary developed societies are the safest, healthiest, and most prosperous that have ever existed, so we might expect that their citizens would have low levels of fearfulness. “Hasn’t one of the central accomplishments of modern civilization,” Norwegian philosopher Lars Svendson asks, “been the overall reduction of fear, by nighttime electrical lighting, insurance policies, police forces, standing armies, the destruction of predatory animals, lightning rods on churches, solid locked doors on all buildings, and thousands of other small designs?” Indeed, rates of violence seem to be at their lowest in recorded history. In addition, life spans of unprecedented longevity mean that few people need to fear dying before old age. Moreover, amounts of economic security greatly
exceed those typical of eras before the post- industrial period. Nevertheless, current community surveys reveal extraordinary high rates of anxiety disorders. Anxiety is the most common class of mental illness: Almost one in five people report having an anxiety disorder in the past year, and almost 30 percent experience one at some point in their lives. These surveys also indicate that the most frequent type of anxiety disorder is specific phobias that involve marked fear about some object. The particular things that people are afraid of are animals (22.2 percent), heights (20.4 percent), blood (13.9 percent), flying (13.2 percent), closed spaces (11.9 percent), water
(9.4 percent), storms (8.7 percent); and being alone (7.3 percent). The second most widespread anxiety condition is social anxiety, which is associated with situations in which people are subject to evaluations by others. The three most widespread forms of social anxiety are public speaking (21.2 percent), speaking up in a meeting (19.5 percent), and meeting new people (16.8 percent).
None of these objects or situations are likely to pose genuine dangers. What accounts for why so many people intensely fear objectively harmless phenomena? Think back to the case that obesity is not a disease but, rather, a
natural product of human tastes for fats, sugars, and salts that enhanced chances of survival in ancient environments. Genes that optimized caloric consumption and stored the excess as fat developed over thousands of generations when sources of calories were usually scarce and always unpredictable. Under current conditions, in which calories are readily available, these ancestral tastes often lead to obesity and associated diseases. The resulting increase in the number of very heavy people does not derive from disordered genes or psychology but from a mismatch between natural biological propensities and modern environments. Tastes for fats, sugars, and salts, however harmful their present consequences might be, are part of our normal genetic inheritance; they are not disorders.
Like our preferences for highly caloric foods, the statistically most common disordered fears, which seem unreasonable and irrational in modern environments, nevertheless result from natural human emotions. Our current fears do not correspond to actual dangers in present situations but seem understandable as reactions that were passed down to us as part of our biological inheritance of fears that did make sense in the prehistoric past. Many currently unreasonable fears arise because natural genes no longer fit the environments in which they must function. Irrational emotions might nonetheless be products of natural physiological responses. Unreasonable, but mismatched, fears raise some fundamental questions about whether or not the results of natural biological forces
should be regarded as disorders.
* Darwin’s most radical insight was that human beings were as much a part of nature as any other form of life. He emphasized a basic continuity across species: “There is no fundamental difference between man and the higher mammals in their mental faculties.” Both mental and physical traits among humans derived from evolutionary descendants and differed in degree, not in kind, from other animals: “We have seen that the senses and intuitions, the various emotions and faculties, such as love, memory, attention, curiosity, imitation, reason etc., of which man boasts, may be found in an incipient, or even sometimes in a well- developed condition, in the lower animals.”
Darwin especially focused on similarities between humans and other primates, noting “that there is a much wider interval in mental power between one of the lowest fishes … and one of the higher apes, than between an ape
and man.” Even faculties such as language, reasoning, morality, and religion, which seem to be uniquely human, are found in rudimentary forms among other animals. All forms of evidence “point in the plainest manner to the
conclusion that man is the co- descendant with other mammals of a common progenitor,” Darwin concluded.
Darwin emphasized not just the link of humans with other species but also the link of humans with each other. He rejected prevailing beliefs that focused on the distinctiveness of various cultures. All peoples were joined by
a core set of characteristics with deep physiological roots. He used evidence taken from an array of sources, including observations from other animals, infants, blind people, and informants from different cultures, to show that human emotions such as grief, fear, joy, anger, disgust, shame, and pride are inherited through a common ancestry. “It follows,” he asserted, “that the same state of mind is expressed throughout the world with remarkable uniformity; and this fact is in itself interesting as evidence of the close similarity in bodily structure and mental disposition of all the races, of mankind.”
Because they were “the same throughout the world,” they provide “a new argument in favour of the several races being descended from a single parentstock.”
Darwin’s encounter with a native of Tierra del Fuego exemplified his complicated thoughts about how overt cultural differences reflect more universal themes: “The term “disgust,” in its simplest sense, means something offensive to the taste. It is curious how readily this feeling is excited by anything unusual in the appearance, odour, or nature of our food. In Tierra del Fuego a native touched with his finger some cold preserved meat which I was eating at our bivouac, and plainly showed utter disgust at its softness; whilst I felt utter disgust at my food being touched by a naked savage, though his hands did not appear dirty.”
* Infants also display much social anxiety. The power of inherited fear of strangers is shown by the fact that infants universally develop this fear when they are about 8 months old and can leave their mothers under their
own power, an adaptation that makes evolutionary— if not current— sense. Studies show that infants as young as age 3 months prefer faces of their own race compared to those of other races, as demonstrated by heightened amygdala
activity. Fears of strangers that underlie many forms of social anxiety thus seem biologically primed. “The temptation to see the other as hostile and subhuman is always present,” according to geographer Yi-Fu Tien, “though it may be deeply buried.”
* Humans are not promiscuous because they and their sexual partners naturally become jealous when their relationship is threatened by additional sexual involvements. Jealousy thus functions to protect monogamous
bonds, to deter sexual infidelity, and to signal a potentially adulterous partner that he or she should refrain from entering a new relationship. According to classicist Peter Toomey, “Jealousy is the glue that holds the sexes together—for the benefit of the family and the survival of the species.” This ancient emotion has not lost its power in modern societies: Sexual freedom, when put into practice, still arouses the wrath of the betrayed partner. Most people, it seems, forego extra-partner relationships because of the vast emotional and logistical complications they entail as well as the strength of the social norm that one should not cheat on one’s lover. Humans have yet to find ways to take advantage of the cultural freedom to engage in sex with a variety of partners while simultaneously retaining enduring relationships. The natural power of jealousy sabotages the cultural promotion of sexual liberty.
* Darwin, for example, observed that danger engenders automatic physical responses: “With all or almost all animals, even with birds, terror causes the body to tremble. The skin becomes pale, sweat breaks out, and hair bristles. The secretions of the alimentary canal and of the kidneys … are involuntarily voided. … The breathing is hurried. The heart beats quickly, wildly, and violently.”
* Consider Darwin’s recounting of his own powerful snake phobia: “I put my face close to the thick glass- plate in front of a puff- adder [a type of venomous snake] in the Zoological Gardens, with the firm determination of not starting back if the snake struck at me; but, as soon as the blow was struck, my resolution went for nothing and
I jumped a yard or two backwards with astonishing rapidity. My will and reason were powerless against the imagination of a danger which had never been experienced.”
Despite Darwin’s knowledge that he was completely safe, he instinctively reacted as if he was in the presence of a dangerous animal. However, there is no hint that Darwin had ever actually encountered any dangerous snakes, which were almost nonexistent in England during the nineteenth century. As he recognized, Darwin’s fear of snakes was not learned but, rather, an inherited, evolutionarily understandable fear that arose because snakes were a common
and genuine source of danger during prehistory.
* The extraordinary frequency of fears of public speaking would not have surprised Darwin, who noted that “almost
everyone is extremely nervous when first addressing a public assembly, and most men remain so throughout their lives.”
* Darwin noted how “the fact that the lower animals are excited by the same emotions as ourselves is so well established, that it will not be necessary to weary the reader by many details.” He emphasized that fear was
probably the evolutionarily oldest emotion that was shared among humans and their distant ancestors alike: “Fear was expressed from an extremely remote period, in almost the same manner as it is now by man; namely, by trembling, the erection of the hair, cold perspiration, pallor, widely opened eyes, the relaxation of most of the muscles, and the whole body cowering downwards or held motionless.”
* Notably, many of the things that children fear have ancestral roots. Consider Darwin’s observation: “May we not suspect that the vague but very real fears of children, which are quite independent of experience, are the inherited effects of real dangers and abject superstitions during ancient savage times? It is quite conformable with what we know of the transmission of formerly well-developed characters, that they should appear at an early period of life, and afterwards disappear.”
The hallmark signs of normal fears among children are that they arise at approximately the age at which they would have been adaptive during prehistory. As Darwin observed, fears of strangers and of animals universally arise
just when infants start to crawl away from mothers at about 6 months of age and so would have been easier victims for predators.
* Charles Darwin pioneered the biological study of emotions. Darwin viewed all core emotions, including sadness, anxiety, joy, anger, and disgust, as naturally emerging in response to specific environmental demands. Each emotion has a particular function that deals with a distinct type of problem. For example, disgust emerges instinctively to signal people to avoid foods that contain toxins, and fear arises so that people will recognize and respond to danger. Darwin also emphasized how distinctive physical expressions accompanied each emotion. Disgust features a wrinkling of the nose, curling of the upper lip, and narrowing of the eyes; fear is expressed through trembling, perspiration, and widely open eyes. Such characteristic expressions serve as communicative signals to avoid poisonous foods or dangerous situations. Humans have a hardwired ability to use facial expressions both to convey their own emotions and to understand the emotions that other people express.
For Darwin, emotions were transmitted as part of the human genome. They developed through processes related to natural selection because people who displayed them in appropriate situations enhanced their chances of survival and consequent reproduction. Although the intensity of core emotions varies widely across different individuals, they are found in all humans and in all cultures. Moreover, they are inherited from earlier species, which displayed similar responses. The functions of the emotions are so basic that they automatically emerge without conscious reflection in response to appropriate environmental stimuli. Because each emotion is designed to emerge in specific circumstances, disorders occur when the emotion arises in inappropriate situations, persists well beyond the situation that evoked the emotion, or features grossly disproportionate and maladaptive symptoms.
Grief, like other core emotions, is biologically grounded and universal. Darwin indicated that the biological foundation of grief was found in the loud cries that human children and offspring of most other animals make as
ways of getting aid from their parents. These are accompanied by typical facial expressions, including a drawing down of the corners of the mouth, drooping eyelids, and hanging of the head, that persist among adults. Darwin noted, “In all cases of distress, whether great or small, our brains tend through long habit to send an order to certain muscles to contract, as if we were still infants on the point of screaming out.” The universal components of sad facial expressions developed because they elicit sympathy, understanding, and social support from others. People easily recognize these biologically based expressions as signs of suffering and become more likely to provide help to the distressed individual. Grief is so widely recognized as a natural response to a loss that
the American Psychiatric Association (APA) uses it in its general definition of mental disorder as the prototype of a nondisordered condition: “An expectable or culturally approved response to a common stressor or loss, such as the death of a loved one, is not a mental disorder.”
* As Darwin stressed, a universal, evolutionarily grounded substrate underlies emotions such as grief. However,
as Herodotus observed, different cultures provide divergent norms for how emotions should be expressed. Cultures also provide the conventions that people use to manage and control their emotional feelings. In addition, the particular circumstances that evoke each emotion often differ across cultural contexts.
* If Darwin was correct in asserting that emotions emerge because of their adaptive functions, then normal grief, as with normal sadness more generally, should have three essential components: It should arise in a specific context, after the death of an intimate; its intensity should be roughly proportionate to the importance and centrality to one’s life of the lost individual; and it should gradually subside over time as people adjust to their new circumstances and return to psychological and social equilibrium. Grief processes can also be pathological when grief emerges in inappropriate circumstances; features extreme symptoms such as marked functional impairment, morbid preoccupations, suicidal ideation, or psychotic symptoms; or persists for extraordinarily long periods of time.
* Darwin focused on three types of evidence—the presence of the emotion among species that arose before humans, among presocialized infants, and in all human cultures—strong indications that some emotion is universal. Grief meets these demanding criteria.
Continuities Across Species
Darwin emphasized the commonality of grief between humans and other species, observing that “the power to bring the grief muscles freely into play appears to be hereditary, like almost every other human faculty.” Nonhuman
primates respond to loss through observable features of expression, behavior, and brain functioning in ways that show clear resemblances to humans. Darwin observed, “So intense is the grief of female monkeys for the loss of
their young that it invariably caused the death of certain kinds.” He noted, and subsequent observers confirmed, that bereaved apes and humans show similar facial expressions, including elevated eyebrows, drooping eyelids,
horizontal wrinkles across the forehead, and outward extension and drawing down of the lips. In addition, both species develop decreased locomotor activity, agitation, slouched or fetal-like posture, cessation of play behavior, and social withdrawal. Chimpanzees make loud distress calls after an intimate dies. Nonhuman primates also react to separations from intimates with physiological responses similar to those that correlate with sadness in humans, including elevated levels of cortisol and ACTH hormones and impairments of the hypothalamic–pituitary–adrenal axis. After the loss of a companion, many dogs show signs such as drooped posture, lack of interest in usual activities, slow movement, sleep and eating problems, and hormonal changes that also characterize bereaved humans. Dolphins stop eating after a mate dies; geese search for a dead companion until they become lost and disoriented.
* Darwin noted how the characteristic mental and physical signs of grief, such as dejection, despair, crying, and weeping, are apparent in very young children.
* Darwin was perhaps the first to comment on the universality of sadness responses: “The expression of grief due to the contraction of the grief-muscles, is by no means confined to Europeans, but appears to be common to all the races of mankind.” Darwin provided a description of grief among the Australian aborigines that was comparable
to the appearance of this emotion among Europeans: “After prolonged suffering the eyes become dull and lack expression, and are often slightly suffused with tears. The eyebrows not rarely are rendered oblique, which is due to their inner ends being raised. This produces peculiarly-formed wrinkles on the forehead which are very
different from those of a simple frown; though in some cases a frown alone may be present. The corners of the mouth are drawn downwards, which is so universally recognized as a sign of being out of spirits, that it is almost proverbial.”
Considerable subsequent research confirms Darwin’s observations that such expressions, especially the contraction of the muscles at the corners of the mouth, are recognized across cultures as representing grief.
* Darwin himself noted, “With the civilized nations of Europe there is also much difference in the frequency of weeping. Englishmen rarely cry, except under the pressure of the acutest grief; whereas in some parts of the Continent the men shed tears much more readily and freely.”
* Why haven’t people taken more advantage of the opportunities that cultural norms now provide for a freer sexual life? One reason for the continued predominance of monogamy might lie in the emotion of jealousy. As Darwin noted,
“Nevertheless from the strength of the feeling of jealousy all through the animal kingdom, as well as from the analogy of the lower animals, more particularly of those which come nearest to man, I cannot believe that absolutely promiscuous intercourse prevailed in times past.”
* Heterosexuality is such a bedrock evolutionary principle that Darwin never mentioned same-sex erotic behavior.