humans are unique in their capacity for emotional tears – a physiological response not commonly observed in the animal kingdom. While the mechanics of tear production are well understood, scientists are increasingly focused on why we cry when moved by joy, sadness, or empathy. New research is delving into the complex neurological and social functions of these emotional tears,exploring how they might impact our nervous systems and even influence the behavior of those around us. This article examines the latest findings on the science of crying, from its biological basis to its potential role in human connection.
We cry when we’re sad, overwhelmed, angry, and even happy. But did you know that humans are believed to be the only species to shed tears in response to emotions?
While many animals vocalize distress as infants, scientists haven’t found evidence they possess the complex brain connections needed to trigger tears in response to feelings. Understanding the function of tears is well-established, but the reasons *why* humans cry, and what emotional tears accomplish, remain a subject of ongoing research.
WHAT ARE TEARS?
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“Tears are composed of five components: mucus, electrolytes, water, proteins, and lipids,” explains Dr. Marie Bannier-Hélaouët, a researcher at the Human Biology Institute in Switzerland. Each component plays a distinct role. For example, proteins have antiviral and antibacterial properties, while electrolytes are essential minerals for bodily functions.
There are actually three different types of tears. “Basal tears are always present on the surface of the eye, keeping it lubricated,” Dr. Bannier-Hélaouët told the BBC World Service program CrowdScience. Reflex tears are triggered when the eye is irritated by something like dust or an insect.
This response is detected by nerve cells in the cornea – the eye’s clear, dome-shaped outer layer, which has the highest concentration of nerve cells in the entire body. These cells can sense temperature, physical strain, and dryness, according to Bannier-Hélaouët.
Messages from these nerve cells travel to a region of the brain called the lacrimal nucleus, which then signals the tear glands to increase tear production.
EMOTIONAL TEARS
The third type, emotional tears, is where things get more complex. The brain’s emotional processing centers also communicate with the lacrimal nucleus, but through more intricate pathways than a simple protective reflex.
According to Ad Vingerhoets, Emeritus Professor of Clinical Psychology at Tilburg University in the Netherlands, crying often reflects an excess of emotional load rather than a single feeling. “Emotions rarely occur in a pure form. They are most often a mixture of different feelings or a rapid shift between them,” he says.
The triggers for emotional tears also change as we age. Physical pain is a significant trigger for children, but becomes less so for adults and the elderly. As people get older, crying becomes increasingly linked to empathy. “We cry not only for our own suffering, but also for the suffering and distress of others.”
Vingerhoets also notes that positive emotions can induce tears, with the beauty of art or nature serving as triggers for some individuals.
WHAT IS THE PURPOSE OF CRYING?
Many people report feeling relief after a good cry, but the scientific evidence supporting this effect is still debated. Lauren Bylsma, a clinical psychologist and associate professor at the University of Pittsburgh, is using heart rate sensors to investigate whether crying actually makes us feel better.
Electrocardiograms (EKGs) record the heart’s rhythm and rate, providing insight into how our nervous system is functioning. Her initial findings suggest that activity in our sympathetic nervous system – which manages the “fight or flight” response – peaks just before crying begins.
“Immediately after crying starts, we see an increase in parasympathetic activity,” Bylsma explains. This branch of the nervous system helps calm us down and promote relaxation.
However, Vingerhoets cautions that crying doesn’t always improve our mood, particularly if we’re experiencing depression or burnout. It also depends on *why* we’re crying. “Generally, we report feeling better when we cry in controllable situations, but not when we cry in uncontrollable ones,” he says.
The people around us can also make a difference.
“If they respond with understanding and offer support and comfort, then you feel better. But if they start to ridicule you or get angry, or if you feel ashamed, then there is no relief,” he explains.
In fact, there’s some evidence that crying can influence how others behave toward us. A laboratory study in Israel found that men who smelled emotional tears from women were less aggressive than those who smelled a saline solution.
Researchers believe tears may function as a social signal indicating we need help, increasing others’ willingness to offer support. Some studies suggest emotional tears may even make us appear more trustworthy, potentially aiding cooperation and mutual support among our ancestors.
When it comes to crying babies, there’s evidence that a baby’s cry activates a brain network in adults that initiates a caregiving response.
Vingerhoets believes that tears in humans may have evolved due to our long period of childhood dependency on our parents. He suggests that a baby’s tears may help reduce aggression in adults, as “crying is very annoying and can make us aggressive.”
“This could be a kind of self-protection mechanism for the baby,” he says.
WHY DO SOME PEOPLE CRY MORE THAN OTHERS?
Bylsma notes that men cry, on average, zero to one time per month, while women cry four to five times. This could be a learned behavior, but the psychologist says its prevalence across different cultures suggests it’s more than that.
“Women are generally more emotionally reactive or more inclined to express their feelings outwardly, and I think crying is just one manifestation of that difference,” she says. “There could be neurological differences, hormonal differences, personality differences.”
Bylsma says there isn’t currently strong evidence that hormone changes throughout the menstrual cycle affect how much we cry, but she believes hormones may play a role due to differences between sexes and during life stages like pregnancy and aging.
She has also researched the impact of personality traits, finding that crying is particularly associated with neuroticism and extraversion. “Neuroticism is associated with depression and anxiety, so that may be why we’re seeing that connection,” she says.
“We also found that people with higher levels of empathy are more likely to cry, likely because they respond to the challenges others are facing.”
Ultimately, crying seems to be linked to social connection.
As Vingerhoets puts it, “Crying seems to function as a kind of exclamation mark [expressing strong emotions]. It can make you realize: ‘Apparently, this is something very important.’”
