Researchers from the University of Bristol studied the reaction of rats to tickling. They found a way to accurately measure the emotions of rodents and noticed that some of them squeaked during this procedure. Tests have shown that the pitch of the squeak is directly proportional to the level of pleasure the rat experiences when tickled. This once again proves that tickling is an ancient mechanism inherited by humans from distant ancestors.
Our body constantly “talks” to us in the language of signals. We'll tell you why evolution came up with some physiological mechanisms and what meaning it put into them.
Tickling
There are different versions of why nature has endowed us with the ability to laugh when tickled, as well as to be afraid of it. One hypothesis is that it signaled to our ancestors about insects crawling on the skin that could be parasites. Hence the fear of tickling, familiar to many of us.
But then it is not clear why tickling causes laughter. Is this a normal reaction to insects crawling on your body? Therefore, other scientists adhere to a different version: tickling is needed to establish contact between the cub and its mother. With its help, without having absolutely anything at hand (or paw), they can play, have fun and get positive emotions. This version is also supported by the fact that with age we stop responding to tickling with laughter. On the contrary, many people find it unpleasant.
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There is an opinion that in previous centuries tickling was used as torture and could bring a person to death. “Most likely, these are fictions and horror stories,” says physiologist, candidate of medical sciences Nikolai Zakharov .
“You can’t tickle a person to death.” The body adapts to the tickling: you either stop feeling it or temporarily lose consciousness.”
Health Don't torture, let go: Why tickling is not so harmless
Text: Olga Lukinskaya
Tickling only at first glance seems like something a priori pleasant , because with it it is easy to cross the line between laughter and tears. Although it is associated with fun and good humor, many people remember tickling as a childhood nightmare. Adults often do not think that children's laughter does not necessarily indicate joy and pleasure and may just be a reflex. We tried to figure out what scientists think about this.
Tickling was studied by Charles Darwin, who came to the conclusion that it was associated with humor. Indeed, we react to funny jokes and tickling in a similar way: we smile, laugh or giggle, a blush appears on our face, the hairs on our skin rise, and tears may even appear. It has been suggested that both humor and tickling create a kind of tension that is resolved by a fit of laughter. After all, would a person laugh if tickling didn't improve his mood? Almost two hundred years after Darwin's publications, scientists began seriously analyzing tickling in laboratories and refuted the opinion of the famous evolutionist.
It is known that a person who has already been made to laugh is in high spirits and reacts better to subsequent funny stories. If humor and titillation are related, then the “warm-up” technique, which is used at concerts when the best jokes are saved for later, should work on them. Scientists at the University of California decided to check if this is true. The study included seventy-two participants and divided them into three groups: some were tickled after watching a comedy program, others were shown it after being tickled, and others were first shown an unfunny video and then tickled. Participants rated how funny the videos were and how intense the tickling was on a scale from zero to seven.
What did it turn out to be? "Warming up" didn't work. Tickling did not make subsequent jokes funnier, and humor did not increase the sensation of tickling. And although the participants laughed during the tickling, the sensation, according to them, was rather unpleasant - and one even called it torture. Yes, tickling and humor cause the same external reactions, but people are happy to watch comedies and listen to jokes, but tickling is perceived as a negative experience. The researchers concluded that laughter in response to tickling and humor is caused by different mechanisms.
Due to the fact that laughter is primarily a social phenomenon, and a person cannot tickle himself, it was believed that the reaction to tickling is a tribute to society, a subconscious disguise of the sensations experienced as pleasant. But in experiments where participants were tickled by a robot, they also laughed. It turns out that laughter when tickled occurs reflexively and is only superficially similar to the reaction to humor.
People are happy to watch comedies and listen to jokes, but tickling is perceived as a negative experience
Why is this necessary? It is believed that tickling is a process that imitates an attack and teaches defense against an aggressor. The most vulnerable parts of the body are usually sensitive to tickling, and a parent who tickles a child actually teaches him to defend himself: push away, change his own position, press his hands to the ribs, protecting his armpits or sides. The reflexive laughter that arises at the same time seems to convey that the attack is not real, that it is all a game.
If tickling is a kind of attack, then it seems logical to explain why a person is not able to tickle himself. This is because the element of surprise is lost; the cerebellum, receiving the corresponding nerve impulses, “teaches” the cerebral cortex not to pay attention to touches on the skin, that is, not to react to them either by laughing or withdrawing. In this case, the brain knows that there is no external aggressor, and simply filters out unnecessary information, not allowing the sensation of tickling to form.
At the same time, tickling is not an unambiguous evil. It can help parents and children form attachment: a light touch from mom or dad makes the child laugh, which in turn makes the parents smile. After a while, to make the baby laugh, it is enough to make a characteristic movement with your fingers, without even touching. The most important thing is not to overuse tickling and not to provoke unpleasant sensations.
It is very important to stop on time. Often requests to stop are not taken seriously by adults. “Well, I’m just tickling you,” the elders react to children’s screams and attempts to push them away. Remember that tickling is an invasion of personal space, and the invasion is painful. There are many examples in history of the use of tickling as real torture, but despite this, it continues to be considered something frivolous. Shouting “enough” and trying to dodge is not a joke, but a defense against invasion.
It is worth mentioning tickling in the context of abuse and sexual violence. More than half of abusers are not strangers, but people close to the child and his family. Tickling for them in many cases becomes one of the first “tests” of reaction, when the abuser observes whether the child complains to the parents; often this does not happen, or the parents say: “It’s okay, he’s just playing with you.” It is best to establish a rule in the family that prohibits strangers from tickling children, and strictly observe it. It is important to teach children about their bodies and acceptable boundaries from an early age, encouraging the “no means no” rule.
Photos: mycteria – stock.adobe.com
Goosebumps
They cover us from the cold. But it happens that their appearance is caused by some event colored by strong emotions - someone’s action, a movie seen, music listened to...
This mechanism, which in the language of science is called piloerection, and in common parlance - “goose bumps”, also came to us from primitive people, and to them from their mammalian ancestors. Goose bumps on the surface of the body are caused by the contraction of tiny muscles in the skin. They raise the hair when freezing so that the heated air lingers longer near the body and does not fly away into the surrounding space.
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The same reflex is triggered in a situation of danger: raised hair makes the animal (look at a cat when it meets a dog) more massive, giving it a frightening appearance. With strong emotional reactions - rage, fear, delight - our nervous system is excited, and this can lead to goosebumps. If we had wool, it would stand on end at that moment.
Piloerection has lost its practical meaning for humans, turning into a rudiment, like some organs of our body - the coccyx, the appendix. After all, Homo sapiens long ago lost their thick coat of fur, and invented clothing to protect them from the cold.
Shiver
This mechanism is similar to the one that causes goosebumps. When a person is cold or scared, he begins to tremble. Why?
Warm-blooded animals, and we are one of them, have a very important physiological ability - to maintain body temperature at a constant level. Trembling your muscles is one way to avoid heat loss and a drop in temperature when it suddenly gets cold. Skeletal muscles begin to make small and frequent contractions, which release heat that spreads throughout the body.
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“When a person is scared, he also begins to tremble. This way we strengthen the functioning of the nervous system, including the autonomic one. All organs and internal systems are tuned to actions related to salvation - either an attack on the enemy, or a swift escape,” explains the scientific secretary of the Institute of Physiology. I. P. Pavlova RAS, candidate of biological sciences Alexander Chuikin .
It is noteworthy that muscle contractions are sometimes used by cold-blooded animals: insects, fish, and reptiles. For example, bees and bumblebees warm their hives and nests due to the intensive work of their wings. They do this to prevent the developing larvae from getting cold.
Cry
The practical benefits of tears are well known to physiologists and ophthalmologists. They moisten the cornea of our eye and thereby protect it from foreign objects (for example, from an eyelash falling into the eye), as well as from drying out, infections, and caustic volatile substances. And thus improve the quality of vision. For example, if a speck or eyelash gets into the eye, the tears will wash it away.
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All land animals have lacrimal glands, which constantly produce a fluid of complex composition. By the way, the chemical compositions of blood and tear fluid are close. Roughly speaking, it is a derivative of blood and also contains several types of salts. And the most useful substance found in our tears is lysozyme. It can kill many microbes and provide disinfection of the eye membranes.
However, why do people cry when they have a strong emotional reaction - grief, fear, compassion, as well as great joy? Scientists are still arguing about the reasons. There are two versions here, and perhaps both are correct. Firstly, crying gives a signal to other people that you feel bad and need help or sympathy. Because Homo sapiens are more socially connected than anyone else in the animal kingdom, empathy and compassion are very important from an evolutionary perspective. Neuroscientists conducted an experiment: they asked photographs to determine the degree of sadness of crying people, while in some photographs the tears were removed using Photoshop. People who had tears removed from their faces seemed less sad to the subjects.
The second hypothesis: tears help the crying person cope with emotional stress and alleviate grief. After all, stress hormones leave the body along with them. Therefore, after crying, we feel relieved.
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Where did she come from?
People of science have still not come to a consensus on why we are afraid of tickles. According to the first hypothesis , tickling is a reflexive human reaction to insects and small animals, which has not disappeared in the process of evolution. That is, with the help of tickling, the body protects us from poisonous creatures that threaten our lives.
According to another version , tickling is a side effect that appeared during the development of the nervous system. And now tickling is considered a borderline reaction of the body to external influences, something between the body’s responses to affection and pain.
Hiccups
Our main breathing muscle is called the diaphragm. Hiccups arise from the fact that spasms appear in it and, with sudden contractions, strong convulsive breaths occur. This is the mechanism, but the cause of hiccups is not completely clear.
“One version is a pinched vagus nerve. It passes from the chest to the abdominal cavity, closely adjacent to the esophagus. When we eat hastily, quickly filling the stomach, the vagus nerve is pressed and irritated, says physiologist, candidate of medical sciences Nina Alekseeva. - The same effect is possible if we take a sharp breath from cold or fear. The body reacts quickly to compression of the nerve: it gives a signal to the central nervous system, and it begins to contract the diaphragm in order to free the vagus nerve, on which the functioning of many of our organs depends. That is, hiccups are such a defense mechanism.”
Hiccups may be a legacy of the very ancient ancestors of humanity, who breathed through gills, some scientists believe. They suggest that there are connections left in the ancient cortex of our brain that are responsible for pushing water out of the gills. An analogy has been noted between hiccups and ventilation in tadpoles.
The smell of sweat
Each of us has encountered a situation when there is a person nearby whose smell of sweat literally makes us sick. Holding our nose, we think: “How can his loved ones tolerate him? Although what kind of loved ones... Who would live with such a stinker? However, it soon turns out that the person has a spouse, and he (she) does not find this smell unpleasant. How so?
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“A lot of glands that secrete sweat are located in the armpit area. The hair growing there enhances the smell of sweat and concentrates it. This smell has an important biological function. Our ancestors used it to find marriage partners. Nature intended it this way: the more different the genotypes of the parents are, the better for their offspring - they will have a more diverse set of genes, explains Nikolai Zakharov. — Scientists have proven that if a person finds someone else’s smell pleasant, it means that its carrier is suitable for him as a sexual partner according to his genotype. But the repulsive smell says otherwise.”
True, there is an opinion that it is not sweat that a person smells, but the microbes that live in abundance on his body. And sweat, which is almost 100% water, only creates good conditions for their reproduction.
Is tickling dangerous?
Most scientists talk about the benefits of tickling, but it can be harmful. Previously, it was used as torture on troublemakers: tied to a bed and tickled with bird feathers, straw or dry grass.
There was another method. The criminal's feet were dipped in salt water. After that, the goat licked them. She has a rough tongue. She used it to tickle the person. For the first 5-10 minutes he could enjoy such an action, then he experienced pain. The man was writhing in agony and could die from an excess of emotions and nervous tension.
Is it possible to die from tickling?
Theoretically this is possible. According to scientists, tickling is a passive protective reaction of the body to irritants. Although the person does not experience severe pain, the brain perceives the tickling as a threat. Laughter is not at all an indicator of pleasure or fun. This is a signal that a person wants to get rid of this condition, a reaction to overstrain of the nervous system.
The body tenses to eliminate the stimulus. The tickle victim may suffocate and die. But this only applies to those who have respiratory problems. There are no recorded cases of death from tickling.
