A Reason to Cry

It was not until I read the New York Times article "The Muddled Trail of Tears" that I began to think about crying from an intellectual perspective (1). I have often wondered why some individuals cry more than others or why I, someone who can cry quite freely when feeling overwhelmed, scared, or sad, am rarely tearful at the end of depressing movies, for instance. However, I have not previously considered the question of why humans, specifically adults, cry in general. After reading the news article, I realized that I had absolutely no sense of the physiological or ecological purpose to crying, and so began my quest. As a result of my research, I've come to believe that adult crying is intimately linked to infant crying, which has a strong evolutionary foundation. In addition, crying is positively reinforced both internally, by a feeling of catharsis, and externally, by the support that it elicits from surrounding individuals.
For this paper, I will employ the common definition of crying as the release of tears in an emotional context. The three main states that produce "psychic tears" are grief and/or sadness, anger, and joy, all of which are considered high levels of arousal (2).    Currently, crying is understood to be something unique to humans, the only species that developed a neuronal link between the tear-producing lacrimal gland above the eye and the area of the brain that processes emotion (3). Therefore, crying depends not just on the link between these two parts of the body but also a brain that has the capacity to process emotions in a way that allows humans to be aware of their needs and want to satisfy them. The absence of crying in closely related species, such which is also unique to humans. Of critical concern is why crying, which must have originally resulted from a genetic mutation, came to be selected for.
I should pause for a moment to note that crying is not the only form of lacrimation, the shedding of tears. Humans, like many other species, constantly produced "basal tears" which keep the eye lubricated, clear of dust, and free from infection and "reflex tears" which rid the eye of irritants, like dust particles or pollen. In a landmark study, biochemist William H. Frey found that these three types of tears have different chemical compositions. Emotional tears contain significantly more types of proteins, high levels of manganese, and lots of hormones, including ACTH (adrenocorticotropin) and prolactin.  Frye postulates that these chemicals are closely related to the various crying states. For example, chronically depressed individuals tend to have higher concentrations of manganese in their brains. ACTH is a stress hormone that increases in concentration with anxiety. Finally, prolactin, associated with women's menstrual cycles, breast development, and postpartum lactation, lowers the threshold to crying and may help to explain female crying behavior. Frey proposed that crying may be a way to flush out these chemicals, but research since has not found support for this. Nonetheless, some psychoanalysts continue to frame crying as a kind of necessary excretory or decontamination process. Finally, more research is needed to determine whether there are differences in composition within the category of "emotional tears," based on the trigger state. (3,2)
We are born to cry. Literally, our first action outside the womb is crying, a response to feeling wet, cold, hunger, starved of oxygen, etc. The sound of our screams and the tears on our face reassure the nurses, doctors, and family that we are healthy babies, and our audience responds with expressions of delight (perhaps even tears themselves), and eagerly reaches out to us positively reinforcing our action.  From this early age of approximately one minute, we begin to realize the efficacy of our crying. People rapidly respond to and alleviate any physical and emotional discomfort that we're experiencing, offering us blankets, a nipple to suckle, and the security of our mother's nurturing arms. In this moment, a mother celebrates her capacity to attend to her child, relieved that she has the power to bring an end to his tears. Therefore, crying may serve a reciprocal function, providing both mother and child with assurance of their bond. Throughout infancy, we continue to cry when faced with some physical or emotional discomfort, whether it's wanting our diaper changed or to be nursed or feeling fearful when left to the loneliness of our crib. Infants have different types of cries-acute shrieks of pain or steady cries of separation of physical discomfort, for example- which together form a kind of vocabulary. It is not until we develop the capacity for speech that crying ceases to be our primary means of communication. Therefore, infant crying may be less about a mental processing of emotions and more similar to the whimpers and screeches common to primates, for example.
As a child grows older and learns to use speech and action to express and satisfy physical discomfort, crying becomes less frequent and more a sign of emotional upset. For example, many children will cry when their mothers drop them off at kindergarten or leave them home with a babysitter on a Saturday night. Here, distress stems from a fear of abandonment which, given its omnipresence among children, seems to be inherently rooted in the subconscious and not necessarily dependent upon the child's experiences. This fear of abandonment becomes less acute as the child gains the capacity to process her observations and realize that her mother will return at the end of the day, as she has every day for the past year. Though the source of tears has changed, it may be useful to continue to think of crying as a form of communication that's employed when verbal communication proves inadequate. Children, like many adults, lack the capacity to understand and express their emotions coherently, and so they use crying to articulate their general state of distress.
In "Why cry? Adaptive significance of intensive crying in human infants," Lummaa et al. offer two many theories for infant crying. First, from an evolutionary perspective, infants may cry to identity themselves as healthy so as not to be labeled as a weakling unworthy of raising: "intensive crying of human infants could be an adaptation to decrease the probability of infanticide. Crying indicates vigor as it demands extra energy...the infanticide hypothesis predicts that an infant's predisposition to intensive crying may enhance its survival" (4). In contemporary American society, infanticide is not a reality, but infants may still cry so as to ensure that they are being watched and their physical needs (upon which their survival is dependent) are attended to. Lummaa et al. also propose a blackmail hypothesis, which argues that infants cry with the knowledge (whether conscious or subconscious) that their parents will immediately respond out of a desire to silence them (4). In Paleolithic or hunter-gatherer society, crying would attract larger animals and pose a risk of predation; in the present, crying draws negative crowd attention poses the risk of social shunning. In public spaces like restaurants, movie theaters, or stores, people glare at a parent with a sobbing baby. This blackmail tactic forces caregivers to give more attention to their child than is in their self-interest. For example, taking an extra half hour to drop off her sobbing child at daycare may cause a mother to be late for an important meeting. Part of the reason parents are so likely to respond to their crying child is because tears are hard to fake, and so parents assume that crying is a sign of genuine distress.
Like infants, adults cry around other people to attract attention and avoid abandonment. Most people interpret crying as a sign of real pain, whether physical or psychological, and feel culpable if they neglect to support a suffering individual. Given that adults tend to cry around one or two other people (from now on referred to as semi-public crying) rather than in large public spaces, adult "blackmail" works slightly differently, for negative social attention is not a practical threat. Instead, people respond to crying so as to avoid feeling guilty for giving a person in pain the cold shoulder. Like children, adults receive positive reinforcement for semi-public cryingÑusually someone stays close to them, diminishing their fear of abandonment and helping to problem solve. Adults may also use crying to emphasize their desperation and get those around them to ignore what's in their best interest. For example, a woman who constantly comforts her crying friend may herself begin to feel emotionally drained and even depressed. In addition, crying might be so effective as to pull the outsider into that individual's emotional state and cause the "comforter" to become distressed as well. At this point, the need for support is mutual, and so the ÒcomforterÓ is less likely to desert the upset individual. The benefits that many people associate with crying may have more to do with the changes in situation or relationships that are brought about by crying than the act of crying itself (2).
Unlike most children, adults also cry in private. In this case, crying is not manipulative, for there is no bystander to be influenced, and the only overt purpose is to bring about some internal relief. It is this internal relief or catharsis that serves as positive reinforcement for private crying. Many distressed individuals are unable to pinpoint their precise emotional state (fear, anger, anxiety, sadness, etc.), and so they use crying to validate their feelings and provide them with an explanation. In other words, a crying individual can say, "Im upset because I am sad, and that's why I'm crying." Crying allows people to turn abstract emotion into something tangible, which is often more manageable and controllable (2). In addition, the limited amount of time that an individual can cry ensures that this state will end. In adults, as in children, crying seems to be the language of distress. Perhaps this psychological state causes individuals to temporarily lose their capacity for higher-level cognition and expression and, as a result, revert back to infancy, when crying is the only operative language.
Many people consider crying cathartic. As explained earlier, this catharsis may be partially due to the change in situation and the potential elimination of the very stressors or triggers that caused the crying. However, the fact that individuals experience this catharsis even when in solitude, when no problems have been solved or new perspective offered, suggests that something may actually occur within the individual that allows for this feeling of relief. According to a study conducted by Rottenberg et al., crying activates both the sympathetic and parasympathetic nervous system and produces arousing and calming effects. While crying, subjects show increasing cardiovascular rates but later present slower breathing and heart rates. The study found that the calming effects last two to three minutes longer than the arousing effects (5). As an athlete, I couldn't help but be struck by the similarities between this cardiovascular pattern and that associated with exerting oneself through rigorous exercise. I have personally found that running produces a feeling of catharsis. In fact, when upset, I tend to go running rather than sit in my room and cry. My cardiovascular rates are higher while running, but they drop dramatically in the twenty to thirty minutes following exercise. It is during this post-run period that I tend to feel tremendous relief and relaxation. Like many other runners, I have long attributed to this feeling to the release of endorphins, and I wonder if the catharsis associated with crying is similar. In other words, perhaps, like running, the raised heart and breathing rates that occur during crying, followed by a steady release of endorphins, accounts for the improvement in one's mental state.
The common assumption is that men and women differ significantly in their crying behavior, but the degree to which this is true and whether the differences are biologically or culturally based remains to be determined. Researchers have found that gender differences in crying do not occur until thirteen, the age at which individuals become more aware of social gender roles and experience an increase in hormones levels (2). Both an understanding of society's acceptance of female crying and a rise in prolactin levels may cause girls to cry more. Men who define their gender role most rigidly differ most significantly from women in crying behavior. Nonetheless, gender differences are also slight enough that they may have more to do with personality than sex (2). In addition, males and females report the same effects or catharsis from crying (6). It is interesting to note that both women and men are more likely to cry in the presence of a woman (2). This finding suggests that adult crying is closely related to infant crying, for both are frequently grounded in a need for a mother or nurturer.
Overall, this study revealed several important findings. First, more research needs to be done on the composition of tears and whether it varies based on an individual's affective state. Second, it seems that adult crying is more intimately linked to infant crying that many people assume. Third, the physiological basis for the catharsis that people associate with crying may not be much different from that associated with other forms of physical exertion. Finally, given that crying may be used in place of "language," it might be important to consider whether people who are better-versed in emotional expression cry less and if training individuals to talk about how they are feeling might decreasing the frequency and/or duration of their crying episodes.


Works Cited

1) Carey, Benedict. 2009 February 3. The muddled track of all those tears. The New York Times. Available from: www.nytimes.com. Accessed 2009 Feb 4.
An introduction to the current questions surrounding human crying.

2) Vingerhoets, AJJM, Cornelius RR, Van Heck GL, Becht MC. 2000. Adult crying: a model and review of the literature. Review of General Psychology; 4 (5): 354-377.
A comprehensive article summarizing the studies and research done on adult crying.

3) Walter C. 2006. Why do we cry? Scientific American Mind; Dec/Jan 06/07: 44-51. Available from: www.sciammind.com. Accessed 2009 Feb 19.
An easy-to-read article on how crying is unique to humans.

4) Lummaa V, Vuorisalo T, Barr RG, Lehtonen L. 1998. Why cry? Adaptive significance of intensive crying in human infants. Evolution and Human Behavior; 19: 193-202. Available from: ScienceDirect. Accessed 2009 Feb 7.
A thorough article that poses several theories for the causes and patterns of infant crying.

5) Rottenberg J, Bylsma LM, Vingerhoets, AJJM. 2008. Is crying beneficial? Current Directions in Psychological Science; 17 (6): 400-404.
A brief summary of the current findings and theories regarding the cathartic quality of crying.

6) Fruyt FD. 1997. Gender and individual differences in adult crying. Pergamon; 22 (6): 937-940.
An empirical study examining the effects of gender and personality on crying.