Buzz
Crying isn't merely about wasting a tissue. Research has shown that weeping may serve a vital evolutionary function, as tears send chemical signals to those around us, and the salty droplets can even produce electricity.
There are also intriguing mysteries, such as why some individuals are more likely to cry on airplanes while others do so when they urinate. The breakthroughs in this area are remarkable. From the surprising beauty of magnified tears to tracking diabetes in real time, the future of human crying holds both peculiar and scientific value.
10. A Symbol of Vulnerability
The reasons behind crying remain a mystery, but there are countless theories. Clearly, there is an emotional aspect, though at times, tears serve as a defense mechanism against irritants like dust and smoke.
In 2009, evolutionary biologist Oren Hasson approached the topic from a survival perspective, asking, “What evolutionary advantage does crying provide?” His analysis proposed that crying signals vulnerability, but in a way that could be beneficial.
Physical signs of helplessness, such as crying, do not pose a threat. As a result, tears may de-escalate violence more effectively than words. They also trigger empathy in others, and any form of protection enhances an individual’s survival chances.
Moreover, crying together can foster stronger connections. Hasson acknowledged, however, that this might only work in certain contexts. Clearly, shedding tears in front of your boss is unlikely to earn you a raise.
9. The Connection Between Happiness and Tears
Crying is often linked to negative emotions such as sorrow and mourning. However, tears can also flow during joyous occasions like weddings or when someone wins an Olympic gold medal. Interestingly, the brain doesn’t differentiate between positive and negative emotions when it comes to triggering tears.
The hypothalamus, a small almond-shaped area in the brain, simply responds to the overwhelming surge of emotion. It does not distinguish between stress or happiness; both are just intense signals sent by the amygdala, the emotional center of the brain.
Once the hypothalamus receives the emotional signal, it triggers the autonomic nervous system. Whether the individual is celebrating a gold medal or mourning a loss, the brain’s reactions follow the same pattern, even though the reasons behind the tears are completely different.
8. The Mystery of Why Onions Make Us Cry
Very few people enjoy chopping onions. This troublesome vegetable makes our eyes tear up uncontrollably, sometimes even forcing our eyelids to close on their own. But why does this happen? The explanation is quite amusing.
The onion is actually defending itself. The act of cutting it releases a chemical compound meant to deter any animal from eating it. This compound is known as propanthial s-oxide.
Once this compound escapes the onion’s damaged cells, it evaporates and rises into the air. When it reaches the eye, it dissolves in the thin film of water that coats the eye, transforming into sulfenic acid. This triggers irritation in the tear glands, causing that familiar sensation of “my eyeballs are on fire.”
Fortunately, the acid isn’t strong enough to cause permanent damage. Not all onions react with the same intensity. While the precise reasons remain unclear, it may relate to how much sulfur the onion absorbed during its growth in the soil.
7. The Virgin Atlantic Survey
In 2011, Virgin Atlantic conducted a survey with clear results: passengers experienced heightened emotions during their flights, leading to more tears. Approximately 41 percent of the male participants admitted to crying secretly under their blankets while on the plane.
While no definitive scientific studies explain why flying in a metal tube high in the air brings out tears, several theories could help. The anxiety of being thousands of feet up while fearing a crash can be overwhelming. Additionally, missing loved ones, boredom that breeds negative emotions, and alcohol consumption may contribute.
Sometimes, flying can cause mild oxygen deprivation, which might impair judgment and thought processes. Add the stress of airport security and traffic, and it’s no surprise that passengers feel mentally drained before they even board the plane. Though Virgin Atlantic couldn’t find a solution, they thoughtfully included 'emotional difficulties' as something to consider in their pre-flight briefing.
6. Tears Could Generate Electricity
Lysozyme is an enzyme found in human tears, egg whites, saliva, and mammalian milk. When crystallized, it displays piezoelectric properties, meaning it can generate electricity under pressure. Quartz crystal is another example of a substance that exhibits this energy.
In 2017, scientists made their first attempt to test whether lysozyme could actually produce electricity. While its potential was known, the challenge was in creating a real electrical current.
The enzyme was spread across films and subjected to mechanical force. After taking measurements, the results revealed that the power generated by the enzyme was comparable to that of quartz.
Lysozyme offers an exciting advantage over other substances—it is biological and non-toxic. This opens up possibilities in the biomedical field, especially for implants requiring antibacterial and electroactive coatings. One day, it might even be used to power devices within the human body.
5. The Shower Cry
The phenomenon known as the 'shower cry' occurs when individuals let their emotions out in the shower. This location for shedding tears is believed by some to be both deeply satisfying and surprisingly common. Researchers acknowledge the difficulty of studying this behavior, as it is not easy to observe a genuine shower cry.
The explanation may lie in a blend of logical reasoning and social psychology. Many adults avoid crying in public, but a shower offers a feeling of comfort and cleansing. The bathroom becomes an ideal refuge for privacy and solace. Plus, the sound of the water effectively masks any sobs.
A large-scale study supported the idea that people prefer to cry in private. Psychologist Lauren Bylsma reviewed data from 35 countries and 5,096 participants. It revealed that 62 percent of people chose to cry at home, and 35 percent would only do so when no one else was around to witness it.
4. Tears Are Unique
At first glance, tears seem to be identical. They are colorless droplets that, due to gravity, tend to be thicker at the bottom and streaked at the top. However, there are three distinct types of tears: reflex, basal, and emotional. Each one is a unique blend of antibodies, oils, and enzymes. The real distinction of tears is revealed when observed under a microscope.
In 2015, Dutch artist Maurice Mikkers invited friends to contribute their tears. They produced tears by looking into a fan, eating hot peppers, chopping onions, or experiencing emotional moments. Mikkers collected the tears using a micropipette, placed them on slides, and allowed them to crystallize.
Once crystallized, Mikkers photographed the tears. Surprisingly, they resembled snowflakes, each displaying intricate and beautiful patterns, such as leaf-shaped crosses. Even when the same stimuli were used, the tears retained their individual uniqueness.
3. Chemical Communication
In 2011, researchers sought out women who admitted to being prone to crying. This was essential for a study in which men would smell the tears of these women. After the researchers collected the women’s tears (induced by watching something sad), the liquid was presented to men alongside saline water. The men couldn’t tell the difference between the two, but the tears had a peculiar effect.
The women’s tears reduced the men’s libido and testosterone levels, even though they never saw the women cry. This discovery marks the first evidence that human tears serve as a chemical form of communication. For now, researchers believe this signal conveys a ‘no’ when a woman is not sexually aroused as much as a man.
The scenario where a woman cries with happiness when her soldier husband returns home—and romance ensues—implies that only tears of sadness carry this mysterious and potent chemical. Interestingly, when men sniffed the tears of other men who had watched a sad video, they too experienced a drop in testosterone and sexual interest.
2. People Who Cry While Peeing
In 2009, British doctors encountered a puzzling syndrome when parents brought in their three-year-old daughter for an examination. When she urinated, she shed tears but didn’t cry. Her face showed a blank expression, and her jaw hung loosely. However, she was perfectly healthy.
To investigate the unusual case further, researchers scoured medical literature and discovered another similar patient. In 1932, a man experienced tears every time he urinated or defecated. A deeper dive into online communities revealed that at least 35 other individuals had the same condition, though none felt compelled to seek medical treatment.
The 1932 case was treated successfully with atropine, a drug that calms nerve activity. This offered a valuable clue. The investigators found a condition called Bell’s palsy, in which damaged or diseased nerves grow back and misconnect with the tear glands. As a result, those affected would ‘weep’ while eating.
It’s possible that another type of nerve abnormality triggers the tears during urination. Another theory is that the cause lies within the brain. Both tear production and urination are controlled by the same brain region known as the pons.
1. Using Tears To Test Glucose
For years, inventors have been on the lookout for a more efficient method to test for glucose. Diabetics can confirm that the traditional fingerprick test, which they must perform themselves, is invasive and uncomfortable.
In 2018, researchers from South Korea made an innovative breakthrough. They tested a special contact lens on rabbits that could monitor glucose levels without causing harm to the eye. It featured a small green LED that would turn off when glucose levels spiked, offering real-time monitoring.
The contact lens was soft, flexible, and utilized tears instead of blood to measure glucose levels. It was designed to be comfortable for wear, not interfering with vision, despite housing an antenna, rectifier, and a number of ultra-thin wires. These components were one-hundredth the thickness of the lens itself, placed along the outer edge.
To check the status of the LED, users would simply need to glance in a mirror. While this is still an improvement over continuous fingerpricks, the device is not yet available to the public. However, researchers are confident it’s only a matter of time before it becomes widely accessible.
