Crying (also called sobbing, weeping, bawling, and blubbering) is shedding tears as a response to an emotional state in humans. The act of crying has been defined as "a complex secretomotor phenomenon characterized by the shedding of tears from the lacrimal apparatus, without any irritation of the ocular structures".[1] The medical term for this is to lacrimate, which also refers to non-emotional shedding of tears.
A neuronal connection between the lacrimal gland (tear duct) and the areas of the human brain involved with emotion has been established. Some scientists believe that only humans produce tears in response to emotional states [2] while others disagree.[3] Charles Darwin wrote in The Expression of the Emotions in Man and Animals that the keepers of Indian elephants in the London Zoo told him that their charges shed tears in sorrow.
In many cultures, it is more socially acceptable for women and children to cry, and less socially acceptable for men to cry.[2]
Tears produced during emotional crying have a chemical composition which differs from other types of tears. They contain significantly greater quantities of the hormones prolactin, adrenocorticotropic hormone, Leu-enkephalin[4] and the elements potassium and manganese.[2]
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The question of the function or origin of emotional tears remains open. Theories range from the simple, such as response to inflicted pain, to the more complex, including nonverbal communication in order to elicit "helping" behavior from others.[5] Some have also claimed that crying can serve several biochemical purposes, such as relieving stress and releasing toxins from the body.[6] However, this view has recently come into question by psychologists who feel that the only reason people believe they think more clearly with a "good cry" is due to social influence. Also, individuals tend to remember the positive aspects of crying, and may create a link between other simultaneous positive events, such as resolving feelings of grief. Together these features of memory reinforce the idea that crying helped the individual.[7]
In Hippocratic and medieval medicine, tears were associated with the bodily humors, and crying was seen as purgation of excess humors from the brain.[8] William James thought of emotions as reflexes prior to rational thought, believing that the physiological response, as if to stress or irritation, is a precondition to cognitively becoming aware of emotions such as fear or anger.
William H. Frey II, a biochemist at the University of Minnesota, proposed that people feel "better" after crying, due to the elimination of hormones associated with stress, specifically adrenocorticotropic hormone. Crying has since then been linked to a burst of intense emotional sensations, such as extreme pain or joy.[9] This, paired with increased mucosal secretion during crying, could lead to a theory that crying is a mechanism developed in humans to dispose of this stress hormone when levels grow too high.
Recent psychological theories of crying emphasize the relationship of crying to the experience of perceived helplessness.[10] From this perspective, an underlying experience of helplessness can usually explain why people cry. For example, a person may cry after receiving surprisingly happy news, ostensibly because the person feels powerless or unable to influence what is happening.
Emotional tears have also been put into an evolutionary context. One study proposes that crying, by blurring vision, can handicap aggressive or defensive actions, and may function as a reliable signal of appeasement, need, or attachment.[11] Dr. Oren Hasson, an evolutionary psychologist in the zoology department at Tel Aviv University explains that crying shows vulnerability and submission to an attacker, solicits bystanders for sympathy and aid and signals shared emotional attachments.[12]
Another theory that follows evolutionary psychology is given by Paul D. MacLean, who suggests that the vocal part of crying was used first as a "separation cry" to help reunite parents and offspring. The tears, he speculates, are a result of a link between the development of the cerebrum and the discovery of fire. MacLean figures that since early humans must have relied heavily on fire, their eyes were frequently producing reflexive tears in response to the smoke. As humans evolved and began to say "Rest in Peace" to their dead, the smoke possibly gained a strong association with the loss of life and, therefore, sorrow.[13]
It can be very difficult to observe biological effects of crying, especially considering many psychologists believe the environment in which a person cries can alter the experience of the crier. However, crying studies in laboratories have shown several physical effects of crying, such as increased heart rate, sweating, and slowed breathing. Although it appears that the type of effects an individual experiences depends largely on the individual, for many it seems that the calming effects of crying, such as slowed breathing, outlast the negative effects, which could explain why people remember crying as being helpful and beneficial.[14]
A common side effect of crying is feeling a lump in the throat of the crier, otherwise known as a globus sensation.[15] Although many things can cause a globus sensation, the one experienced in crying is a response to the stress experienced by the sympathetic nervous system. When an animal is threatened by some form of danger, the sympathetic nervous system triggers several processes to allow the animal to fight or flee. This includes shutting down unnecessary body functions, such as digestion, and increasing blood flow and oxygen to necessary muscles. When an individual experiences emotions such as sorrow, the sympathetic nervous system still responds in this way.[16] Another function increased by the sympathetic nervous system is breathing, which includes opening the throat in order to increase air flow. This is done by expanding the glottis, which allows more air to pass through. As an individual is undergoing this sympathetic response, eventually the parasympathetic nervous system attempts to undo the response by decreasing high stress activities and increasing recuperative processes, which includes running digestion. This involves swallowing, a processes which requires closing the fully expanded glottis to prevent food from entering the larynx. The glottis, however, attempts to remain open as an individual cries. This fight to close the glottis creates a sensation that feels like a lump in the individuals throat.[17]
According to a study of over 300 adults, on average men cry once every month; women cry at least five times per month,[2] especially before and during the menstrual cycle when crying can increase up to five times the normal rate, often without obvious reasons (such as depression or sadness).[18]
According to the German Society of Ophthalmology, which has collated different scientific studies on crying, women cry on average between 30 and 64 times a year, and men cry on average between 6 and 17 times per year.
Men tend to cry for between two and four minutes, and women cry for about six minutes. Crying turns into sobbing for women in 65% of cases, compared to just 6% for men. Until adolescence however, no difference between the sexes was found.[19]
Although crying is an infant's mode of communication, it is not limited to a monotonous sound. There are three different types of cries apparent in infants. The first of these three is a basic cry, which is a systematic cry with a pattern of crying and silence. The basic cry starts with a cry coupled with a briefer silence, which is followed by a short high-pitched inspiratory whistle. Then, there is a brief silence followed by another cry. Hunger is a main stimulant of the basic cry. An anger cry is much like the basic cry; however, in this cry, more excess air is forced through the vocal cords, making it a louder, more abrupt cry. This type of cries is characterized by the same temporal sequence as the basic pattern but distinguished by differences in the length of the various phase components. The third cry is the pain cry, which, unlike the other two, has no preliminary moaning. The pain cry is one loud cry, followed by a period of breath holding. Most adults can determine whether an infant's cries signify anger or pain.[20] Most parents also have a better ability to distinguish their own infant's cries than those of a different child.[21] A 2009 study found that babies mimic their parents' pitch contour. French infants wail on a rising note while the Germans favor a falling melody.[22]
There have been many attempts to differentiate between the two distinct types of crying (one negative and one positive). Different perspectives have been broken down into three dimensions to examine the emotions being felt and also to grasp the contrast between the two types.[23]
Spatial perspective explains sad crying as reaching out to be "there," such as at home or with a person who may have just passed away. In contrast, joyful crying is acknowledging being "here." It emphasized the intense awareness of one's location, such as at a relative's wedding.[23]
Temporal perspective explains crying slightly differently. In temporal perspective, sorrowful crying is due to looking to the past with regret or to the future with dread. This illustrated crying as a result of losing someone and regretting not spending more time with them or being nervous about an upcoming event. Crying as a result of happiness would then be a response to a moment as if it is eternal; the person is frozen in a blissful, immortalized present.[23]
The last dimension is known as the public-private perspective. This describes the two types of cryings as ways to imply details about the self as known privately or one's public identity. For example, crying due to a loss is a message to the outside world that pleads for help with coping with internal sufferings. Or, as Arthur Schopenhauer suggested, sorrowful crying is a method of self-pity or self-regard, a way one comforts oneself. Joyful crying, in contrast, is in recognition of beauty, glory, or wonderfulness.[23]
There are three types of tears: basal tears, reflexive tears, and psych tears. Basal tears are produced at a rate of about 1 to 2 microliters a minute, and are made in order to keep your eye lubricated and smooth out irregularities in the cornea. Reflexive tears are tears that are made in response to irritants to your eye, such as when chopping onions or getting poked in the eye. Psych tears are produced by the lacriminal system and are the tears expelled during emotional states.[24]
The lacrimal system is made up of a secretory system, which produces tears, and an excretory system, which drains the tears. The lacrimal gland is primarily responsible for producing emotional or reflexive tears. As tears are produced, some fluid evaporates between blinks, and some is drained through the lacrimal punctum. The tears that are drained through the punctum will eventually be drained through the nose. Any excess fluid that did not go into the punctum will fall over the eye lid, which produces tears that are cried. [25]