The evolution of kissing: how did it originate?

What is the evolution of kissing? How did this practice originate in human beings?

Kissing, the act of pressing the lips against the surface of another's lips as a sign of affection, affection or desire, is a widespread expression in modern society. If we reflect on this emotional demonstration beyond its psychological meaning, we find ourselves faced with a custom that can be counterintuitively harmful, as we will see in later lines.

The act of kissing can contain some 80 million bacteria that are transmitted to the receiver, and not all of them are necessarily good. Any pathogen found in saliva can be transmitted by this mechanism of affection, be it a virus, bacterium, fungus or other sufficiently small parasite.

It is for this reason that, if we apply common sense, it is time to ask ourselves: What is the evolution of kissing? What is the evolutionary meaning of a behavior that can endanger the survival of the person who performs it? How did kissing come about?

As you can see, an act apparently so simple and devoid of biological meaning (although charged with emotional meaning) contains a series of unknowns to be solved. Dive with us into the world of kissing, not from a romantic point of view but from a biological one, because the reflections that arise will surprise you.

The evolution of kissing: from the biological to the romantic.

The first answer necessary to chain the rest of the pertinent questions is, indeed, to discover what is the origin of the kiss. The first record of kissing-like behavior as we know it today is found in the Vedas.The Vedic religion, ancient texts of Indian literature that laid the foundations of the Vedic religion (prior to Hinduism). Thus, this first evidence dates back 3,500 years.

Moreover, civilizations as ancient as the Sumerians already created poems in which the presence of the kiss was evidenced as an act of affection and romanticism. We will not continue citing historical examples, because it is clear the concept we want to convey: the kiss has been with humans for many, many years.

What is more striking (and certainly more difficult to explain) is to try to answer this question: why did the kiss arise? There are different theories that explore a possible answer.and we show them below.

Do we learn to kiss or is it part of our genetic code?

The first consideration in this area is whether kissing is a learned act or one based on the most primal human instinct. Unfortunately, we do not have a clear answer, but there has certainly been some speculation.

In favor of the theory that that this display of affection is instinctive, we find several pieces of evidenceFor example, behaviors similar to kissing are widespread in the animal kingdom, be it beak rubbing in birds, licking in dogs or contact between antennae in insects. However, we also found an animal that kisses exactly like us: the bonobo.

Bonobos exchange saliva in many situations, as they use kissing to calm tension after fights. to defuse tension after hierarchical fights, to comfort each other, to strengthen group relationships, or simply for no apparent reason. This is not entirely surprising, since we share 98.7% of our DNA with these primates, which certainly explains why certain behaviors are so similar between the two species.

In any case, the evolutionary concept of "kissing" is something that is usually attributed beyond the primate group (or birds, perhaps) in a mistaken way. Can we conceive of the antennal game between insects as an act of affection? Unfortunately, there is insufficient evidence to attribute such a meaning to it. Yes, it may serve for recognition between conspecifics and to provide some information from the male to the female before reproduction, but from there to affection or affection... there is a long way to go.

On the other hand, there are some arguments that weaken the theory that the act of kissing is an inherited behavior. Ninety percent of cultures kiss (although not all of them romantically, as we will see below), but the remaining percentage do not.How can we explain that these individuals do not kiss if it is something genetic and embedded in all our species?

Why do we kiss?

We kiss out of passion, romanticism, affection, affection, etc. All these psychological impulses are well described, but that is not what we are talking about. Why do we kiss like animals? What is the primitive evolutionary explanation for this behavior? Again, there are several theories on this subject, none of which have been fully confirmed.

According to several researchers, the act of kissing may have evolved in humans from the previous behavior of regurgitating food. previous behavior of mouth-to-mouth regurgitation of food from mother to child, a form of parental care relatively common in humans.This is a relatively widespread form of parental care in the animal world (especially mammals and birds). Since we do not want to generate nausea in any reader, we will limit ourselves to say that the most passionate (French) kiss and regurgitation behavior share quite similar mechanisms.

On the other hand, it has been postulated that the kissing responds to a clear mechanism of sexual selection. From a biological point of view, when we approach the face of another human being, we obtain a lot of valuable information (albeit subconsciously). For example, studies have found that certain sample groups of women are more biologically attracted to men with pheromones that show that their genetic profile is distant: we explain.

From an evolutionary point of view, reproduction among relatives is deleterious for any species, as it reduces the genetic variability of the population and therefore makes it more vulnerable to possible environmental changes. Pheromones can inform the two components of a pair (to a certain extent) how genetically related they are, so as to avoid reproducing if they are related and give rise to offspring with lower variability. Of course, these assumptions have to be taken with a grain of salt, since the experiments are carried out in laboratory environments and the social component is not taken into account.

In addition to such an abstract concept as pheromones, other mechanisms are much more obvious. For example, bad breath is often indicative of an underlying disease or pathology.. Approaching the face of a potential partner allows us to suspect their state of health, and therefore, the quality of their genes.

Kissing is not as universal as previously thought

Until recently, it has been recurrently repeated in the media that kissing is present in 90% of cultures. This is half true half false, as a study published in 2015 demonstrated that kissing as a romantic act is only present in 46% of the cultures sampled..

Yes, most individuals on the planet kiss (e.g. a mother to a child), but less than half of us do so with sexual intent. This, of course, calls into question again the theory that kissing as we know it from the West is a behavior hardwired into the human genome.

Other considerations

In addition to providing biological evidence of the individual we kiss, not everything is based on a set of genetic benefits. Kissing also promotes the release of oxytocin, dopamine and endorphins, essential neurotransmitters in the human genome.neurotransmitters essential to feelings of pleasure and well-being.

Furthermore, it has been shown that in couple relationships, an increase in the frequency of kissing decreases stress levels, strengthens the bond and even results in a reduction in Blood cholesterol levels. Therefore, in addition to its subjective emotional component, kissing has a clear physiological benefit: improving the well-being of the individual.

Summary

As we have seen, the evolution of kissing is a subject that moves between gray scales and never in absolute statements. The very evolutionary origin of kissing is a matter of constant speculation, since We are not even clear whether kissing is a behavior embedded in the genome of our of our species or whether it is a trait acquired by learning.

In any case, one thing is clear: in spite of the diseases that can be transmitted through it, kissing brings much more positive than negative. Diseases come and go quickly, while maternal affection, the building of an emotional bond, affection and love are concepts that are much more permanent over time.

Bibliographic references:

• Castleman, M. (2015). Kissing. The international encyclopedia of human sexuality, 633-647.
• Jankowiak, W. R., Volsche, S. L., & Garcia, J. R. (2015). Is the romantic-sexual kiss a near human universal?. American Anthropologist, 117(3), 535-539.
• Whats in a kiss? The science of smooching, britishcouncil.org. Retrieved September 30 from https://www.britishcouncil.org/voices-magazine/kiss-science-smooching#:~:text=A%20kiss%20might%20seem%20like,being%20a%20basic%20human%20instinct.
• Why do we kiss, livescience.com. Recogido a 30 de septiembre en https://www.livescience.com/32464-why-do-people-kiss.html#:~:text=Today%2C%20the%20most%20widely%20accepted,people%20will%20make%20strong%20offspring.