The emergence of monogamy in ancient primates was explained by neurochemistry

Looking at the explanatory dictionary, you can see that a polygamous man is a person who simultaneously maintains sexual relationships with several women (two or more). In addition, the concept of female polygamy is highlighted.

A polygamous man is... What is a polygamous family?

History of polygamy

In primitive society, such a thing as monogamy did not exist at all. For our distant ancestors, polygamy was simply necessary - only thanks to it was it possible to constantly continue the clan and increase its number. In turn, this is what allowed the tribe to survive in harsh conditions. The hierarchy within the tribe itself was of great importance. Thus, the leader, the strongest representative of the genus, had the unconditional right to fertilize any of the females, and after him, in descending order of importance, the other males. At the same time, natural selection occurred, because stronger and more resilient children were born from stronger males. Why is the word “polygamy” now most often used in a negative context?

Notes

  1. Around the world. Proof of a truism...
  2. Victor Dolnik.
    Is life the clue to gender or is gender the clue to life? (Russian). ethology.ru (January 28, 2004). — Man: mind plus instincts. Retrieved March 16, 2012. Archived June 24, 2012.
  3. Why are more boys born than girls? Retrieved December 20, 2020.
  4. Polygamy, in botany // Encyclopedic Dictionary of Brockhaus and Efron: in 86 volumes (82 volumes and 4 additional). - St. Petersburg, 1890-1907.

Transition from polygamy to monogamy

As evolution progressed, more stable and strong ties began to emerge between individual representatives of different tribes. Even the beginnings of marriage appeared. However, they continued to be based on polygamy. A husband could have any number of women on his side, but his wife, in case of betrayal, risked being stoned. By the way, it was in this version that harems were born.

Over time, issues of property division began to arise. They were solved very simply - since males dominated society, a male child should also inherit everything. In order not to leave all the property acquired over a long life to someone else's offspring, the head of the family had to be sure of his paternity. This is where the question of determining paternity arose. Nowadays, this problem is solved in just a couple of hours - the child and father undergo special tests, and then find out the result almost instantly. Then the only way out of the situation was monogamous marriage.

Religions played a major role in the strengthening and development of monogamous marriage. At the same time, purely human relationships developed - in addition to the natural instinct to prolong one’s own kind, affection and feelings began to play the role.

Monogamy and its benefits

According to scientists and doctors, humans are monogamous by nature.

It’s easy to guess that translated from Latin, the term “mono” means “one,” and the definition of “monogamy” is the preference of one sexual partner over all others. This means that monogamy is the ideal form of human relationships. Why, then, do many couples and families get destroyed, and the statistics of infidelity are simply terrifying?

According to the same scientists, the reason for everything is the lack of trust in the family. Constant suspicions of treason, jealousy, mistrust - these are the factors that are considered the main problem. As mentioned above, not all couples can boast of complete and absolute trust in their other half and harmony in the family.

For others, the salvation of marriage is swinging and freedom in relationships. The remaining representatives of monogamous couples who could not control their own jealousy are doomed to divorce.

You can correct the situation in different ways. So, the best solution is to visit a family psychologist, who will help you find the reasons for jealousy and mistrust, and also explain on what principles a strong marriage is based.

It is important to see the positive qualities in your partner and not look for the negative. Both women and men still need to improve in life, pleasantly surprising their soulmate, bringing new colors to your marriage.

Is it true that all men are polygamous?

Many representatives of the stronger sex justify their love affairs by saying that they are polygamous by nature and are unable to resist the influence of instincts. The question naturally suggests itself: “Perhaps a polygamous man is normal?” Let's try to figure it out.

Why are men polygamous? It is believed that the reason really lies in ancient instincts - primitive males tried to impregnate as many females as possible and leave as many heirs as possible. Is it likely that these instincts are still active today?

Physiologically, men are indeed prone to polygamy. However, we should not forget that man differs from animals in the ability to think and act contrary to the call of nature. Therefore, it is not easy to remain faithful to a man all his life, but it is possible. However, not only the husband, but also the wife needs to remember this - by surrounding her “male” with love, care, understanding, giving him everything he needs for happiness, she protects herself from betrayal. After all, a decent person who knows how to be grateful will appreciate what his chosen one does for him. And at least out of a sense of respect, he will not hurt her feelings by going “to the left.”

However, there are people who believe that cheating on the male side is normal; they sincerely do not understand why girls are so categorical about this. The main thing here is to be initially honest with your other half, immediately dotting all the i’s.

What kind of relationship is right for you?

Most people instinctively know whether they have given up a monogamous or polygamous partnership. However, for the small minority of people who may be unsure, there are some telltale signs. First of all, the reason for monogamy or polygamy. Entering into any partnership for the wrong reason is a bad idea. Unfortunately, many people are afraid of being alone and therefore strive for a relationship. Other people may enter into monogamous or polygamous unions in order to prove a point. Both reasons (and others like them) are usually recipes for disaster.

Although polygamy has gained more attention and acceptance, the stigma has not completely disappeared. This has led some people to question whether polygamous relationships are better for them.

When determining whether to enter into a monogamous or polygamous relationship, another critical component comes in the form of your values. A person who believes in tradition is better suited to monogamous unions, and that's okay. Many people prefer traditional relationships and should seek them accordingly. Luckily, people who choose monogamy tend to naturally gravitate towards people like them. Just like those who advocate polygamy usually find each other.

What about them?

We have already found out what polygamous means. Now let's talk about the common myth that all animals are polygamous. This is far from true. Relationships between representatives of different sexes in the animal world are also built differently. For example, some birds get together only for the period of hatching eggs and hatching chicks, and the next time they look for new partners. There are arctic foxes, foxes and even some species of fish that practice an exclusively monogamous lifestyle. But, say, beavers can behave differently depending on their habitat.

It is noteworthy that in the animal world, even polygamous males try to impregnate strong, healthy females. A polygamous person, hiding behind his instincts, most likely does not even think about procreation and survival. At a minimum, in this case, he should have chosen exactly those women who could theoretically bear and give birth to healthy offspring (strong, with wide hips, and not just beautiful breasts). If this is not the case, then talk about polygamy is nothing more than empty words to justify one’s own promiscuity.

Benefits of Polygamous Relationships

So, polygamous relationships are a form of contact between men and women in which one partner maintains contact simultaneously with several people of the opposite sex (yes, polygamy is characteristic not only of men, but also of some women).

Let's leave aside questions of morality and look at what advantages a polygamous family can have. Let us immediately note that we are not talking about one-time infidelities, but about a real polygamous family (as in Arab countries, where a man can have several wives at once). Moreover, this is a full-fledged family, where each member has his own responsibilities, rights, etc.

Actually, the main advantages of polygamous families:

  • from a biological point of view, a variety of sexual relationships has a beneficial effect on the vitality of the offspring;
  • a polygamous family is a rather difficult step for a woman, and if she agrees to this, then only on the terms of a deliberate agreement;
  • as a consequence of the previous paragraph, the divorce rate in polygamous families is practically zero.
  • In addition, it should be mentioned that men can have multiple wives (in countries where this is allowed) only if they have enough money to support the entire harem. That is, the wives of this “sultan” will be 100% sure that their children will never need anything, will not starve and will receive a decent education.

The view of psychologists

Despite the fact that monogamy is a generally accepted way of creating a family, infidelity among spouses is very common. Psychologists believe that people must “mature” for monogamous relationships, and this is not easy. The fact is that it is quite possible for people to have deep feelings for one person, while at the same time sometimes being “infatuated” with someone else. The infatuation quickly passes, but during this period the likelihood of committing treason increases sharply. It also happens that a person cheats in a state of passion, for example, while intoxicated. Cases of long-term infidelity are recorded much less frequently, when a person has a married partner and another, extramarital partner, for a long time.

The fact is that people’s feelings are a complex and confusing system, sometimes quite contradictory. Not everyone is able to resist a charming member of the opposite sex, even if they have a permanent partner. Some people have low moral standards; they don’t even try to resist, sometimes even specifically hunting for extramarital “adventures.”

There are those who are sure that monogamy is contrary to human nature. Such people start relationships by agreeing in advance with their partner on such a situation. Such marriages cannot be called traditional, but sometimes they exist quite successfully. This approach to relationships is called polygamy.

Disadvantages of Polygamous Relationships

Now let's talk about the cons. First of all, a polygamous man is a person who must pay enough attention to each of his partners. To put it mildly, few succeed in this. And although no one in the family lacks material wealth, some psychological discomfort may still occur.

You should also not think that you can get used to a polygamous marriage, and that over time there will not be a hint of jealousy. Most likely, you will simply have to come to terms with it as an inevitable fact, but nothing more.

On top of that, it has been noticed that a polygamous person, who already scatters his attention among several partners, devotes less time to children.

Polygamy and domestic mentality

Someone might object and cite the example of happy polygamous families in the East. However, there are several factors to consider. Firstly, polygamy is not prohibited by Islam (unlike Christianity, which is widespread among us). Secondly, girls are raised in this culture from a very early age; they are psychologically prepared to become a “senior” or “junior” wife.

It should also be taken into account that in Arab countries women have practically no rights. Our girls, who have fallen under the powerful current of expansion, are unlikely to be able to share their man with someone. Therefore, the legalization of polygamous marriages in our country, most likely, will not lead to anything good - there is simply no suitable psychological foundation for this, which has been formed over centuries.

What's in religion?4

Christianity only accepts monogamy. According to the Bible, a man can only be happy if he loves one woman. It is for this reason that God created the pair of Adam and Eve as the ideal of a highly spiritual marriage.

In Judaism, polygamy is not prohibited, but it is possible only under certain circumstances, for example, if the first wife is barren, but the family must be continued. However, monogamy is still considered sacred for the protection of women.

Buddhism by its nature is not judgmental, this also applies to multiple marriages, but it also does not welcome them, they rather go beyond the scope of religion. But Tibetan Buddhists accept one woman having two spouses at once.

Hinduism allows polygamous relationships as long as they do not create problems, thus degrading the man.

Islam is the only world religion that has always approved of polygamy, which is due to the ancient cultural and social context.

Does female polygamy exist?

Unlike men, women do not have historical background for this phenomenon. There are simply no corresponding mechanisms in the genetic code of representatives of the fair sex. Female polygamy is nothing more than a psychological phenomenon, even a deviation from the norm. After all, girls are genetically programmed not to have children from as many males as possible, but to choose the strongest, hardiest and most intelligent representative of the species and give birth to offspring from him. In fact, polygamous women go against the genetic code and their natural destiny.

The emergence of monogamy in ancient primates was explained by neurochemistry

Skull of Ardipithecus ramidus
at the National Museum of Natural Sciences of Spain

Tiia Monto / Wikimedia Commons

American anthropologists and neuroscientists led by Owen Lovejoy from Kent State University in two articles published in the Proceedings of the National Academy of Sciences,

proposed an explanation for the social monogamy that arose among the ancestors
of Homo sapiens
and the subsequent reproductive success that allowed people to populate almost the entire planet.
In one of the articles, scientists hypothesized that social monogamy in the ancestors of Homo sapiens
arose due to neurochemical changes in the striatum, a part of the brain that, among other things, produces dopamine and serotonin. In another publication, researchers attributed human reproductive success to the high survival rate of young females, which they believed became possible after the emergence of monogamy.

In the early 1990s, researchers discovered the remains of hominins in Ethiopia that lived about 4.4 million years ago. After the species Ardipithecus ramidus

was described, anthropologists called it the direct ancestor of australopithecines - great primates who lived in Africa 4.2-1.8 million years ago and whose descendants became people. Ardipithecus was small in stature, about 120 centimeters, and their brain volume was 300-350 cubic centimeters (about 20 percent of the brain volume of modern humans). Scratches and marks on the teeth of ancient primates indicated that they were omnivores and ate a lot of fruit. They mostly fed in forests, but periodically searched for food in savannas. Unlike the fangs of modern chimpanzees and gorillas, which use them to argue over territory and females, the fangs of male and female Ardipithecus were practically the same in size, and in general the males were not very larger than the females. Judging by the structure of the skeleton, the ancient primates walked on two legs, but at the same time climbed trees well.

In 2009, based on the results of many years of studying the remains of Ardipithecus, a special issue of Science

, which published an article by American anthropologist Owen Lovejoy. The scientist suggested back in the early 80s that one of the main factors that led to the emergence of man was the emergence of social monogamy, and not the appearance of stone tools or an increase in brain volume. In a 2009 paper, Lovejoy offers evidence for his hypothesis. Male modern apes have much larger canines than females. Males use them as weapons when they try to assert their dominant status. In Ardipithecus, they were almost identical in size in both of them, from which the anthropologist concluded that, apparently, they managed to get along with other males without fighting. Also, ancient primates developed upright walking, possibly due to the fact that they began to look for food on the ground and periodically go out into the savannah. But upright walking is not the fastest or most energy-efficient way to move. In addition, it could lead to injuries. Therefore, Ardipithecus, especially females with cubs, could become easy prey for predators.

It should be noted that modern apes, humans, and, apparently, their ancestors adhered to the K-strategy of reproduction. The species “chosen” by her reproduce relatively rarely and produce few young, and the mother then raises them for several years, investing a huge amount of resources. The R-strategy, on the contrary, is about quantity: such species reproduce often and in large quantities, but take little care of their young.

In conditions where males fight for territory and females (in this case, females also get it, so some of them die), and females are forced to take care of the cub for a long time, alone obtaining food for both and risking becoming a victim of predators, the chances of survival of the species are very high few. However, the direct descendants of Ardipithecus - Australopithecus - not only survived, but also spread throughout much of Africa. Lovejoy explains this paradox by the emergence of social monogamy in Ardipithecus - the male mated with only one of the females, and in return provided her with food. So the females had the opportunity to get food for themselves and for the cub, and at the same time not get into the teeth of a predator. In addition, she had more time to care for the baby. According to Lovejoy, upright walking evolved in part because males needed to bring food to the female. And the females obviously chose those who brought more food. In return, the male received regular sex and ensured the transmission of his genes to his offspring. Therefore, he did not have to prove his dominant position and quarrel with other males. Accordingly, the need for large fangs also disappeared. Probably, females also “helped” by choosing not fighters, but those males who took better care of their offspring. However, a problem arose: the females of modern apes “announce” to all interested males that they have begun ovulation and are ready to mate. In female chimpanzees in particular, the skin around the genitals becomes swollen and red. Monogamous Ardipithecus couples did not need such “advertising”. Therefore, according to Lovejoy's hypothesis, females have learned to hide the moment of ovulation so as not to attract the unwanted attention of strange males.

It should be noted that Lovejoy's theory is not accepted by all anthropologists. Thus, Russian anthropologist Marina Butovskaya suggests that male ancient hominins mated with several females, and females mated with several males, but at the same time they refrained from sexual relations with close relatives.

The emergence of social monogamy according to Owen Lovejoy's hypothesis

Owen Lovejoy / Science, 2009

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In a new study, scientists led by Lovejoy offer a neurochemical explanation for the emergence of social monogamy. Researchers believe that changes in the striatum, or striatum, played a key role in this process. This part of the brain is associated, among other things, with the “reward center,” planning, decision-making and “autonomous” behavior, and, on the other hand, with the ability to adapt to the behavior of others. Behavior, in turn, depends on the concentration of neurotransmitters in the striatum: dopamine, serotonin, acetylcholine and neuropeptide Y.

Researchers suggest that high concentrations of acetylcholine in the striatum increase aggressiveness and provoke dominant behavior. Increasing the amount of serotonin affects the inhibition of impulsive behavior and cognitive control of emotions - key skills for cooperation and forming partnerships. At the same time, a decrease in the concentration of serotonin in the striatum increases impulsivity, including those unacceptable for social relationships, for example, outbursts of aggression. Scientists associate an increase in the concentration of dopamine in the striatum with conformity (change in behavior under the influence of other people) and satisfaction from communicating with others. If an increase in dopamine concentration is accompanied by a decrease in acetylcholine concentration, it promotes social behavior and increased sensitivity to social cues. The role of neuropeptide Y in the striatum in social behavior is still unclear, but increasing the concentration of this substance in the cerebrospinal fluid of patients with schizophrenia improved their social skills.

The researchers analyzed levels of neurotransmitters in the striatum of monkeys (capuchin monkeys, pig-tailed macaques and anubis baboon), great apes (chimpanzees and gorillas) and humans. Humans, compared to other primates, have higher levels of dopamine, serotonin and neuropeptide Y, and, at the same time, lower levels of acetylcholine. According to the authors of the work, this combination helps to increase empathy, the ability to recognize social signals, altruism and conformity. At the same time, lowering acetylcholine levels appears to have reduced the aggressiveness of human ancestors. The researchers noted that chimpanzees, gorillas and humans had higher levels of serotonin and neuropeptide Y than monkeys. These neurotransmitters may have reduced impulsive behavior and enhanced social skills in apes and humans. At the same time, acetylcholine levels in great apes were higher than in humans. Scientists call the combination of increased concentrations of dopamine and decreased concentrations of acetylcholine in the striatum unique for humans. According to them, perhaps it was this that determined the emergence of social behavior specific to people.

The role of the striatum in the origin of man according to Lovejoy. As primates transitioned from the R-strategy to the K-strategy of reproduction, their levels of serotonin (5HT), which reduced aggression, and neuropeptide Y (NPY), which improved social skills, increased in their striatum. In the striatum, modern chimpanzees and gorillas have high levels of acetylcholine (ACh) and low levels of dopamine (DA). Modern humans, on the other hand, have low levels of acetylcholine (Ach) and high levels of dopamine (DA), which makes them more social and less aggressive than apes.

Mary Ann Raghanti et al. / PNAS, 2018

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The authors of the article believe that a decrease in the level of acetylcholine in the striatum, which reduces aggression, and an increase in the level of dopamine, which increases satisfaction from communicating with others, was key to the emergence of social monogamy in ancient people. In some species of modern mammals, social and occasionally genetic monogamy occurs (, ,), but territorial. A couple with cubs does not welcome not only predators, but also other individuals of their species that wander into their territory. People, in general, willingly communicate and establish social connections not only with members of their family, but also with other people.

In another article published in the same issue of Proceedings of the National Academy of Sciences

anthropologists propose a hypothesis to explain the phenomenal reproductive success of people, which allowed them to spread across the planet.
The researchers used macaques as model animals. Crab-eating macaques ( M acaca fascicularis
) and rhesus macaques (
M acaca mulatta
) are the most successful primates after humans in terms of “taking over” territories.
They settled in southeast Asia and were able to survive not only in the wild, but also in urban environments. According to researchers (, ), the annual increase in populations of these species can reach 10-13 percent. But some macaques, such as the Ceylon macaque ( Macaca sinica),
are found only in limited areas and have little population growth. To understand what caused these differences, the authors of the article used data from primatologists (, ,) who observed monkeys and compared the survival rates of female cynomolgus, rhesus and Ceylon monkeys.

In females of all three species of macaques, reproductive age occurs with a slight difference: in rhesus macaques - at four years, in Ceylon macaques - at five, and in cynomolgus macaques - at 5-6 years. At the same time, female rhesus and crabeaters give birth to cubs for 19-20 years. In Ceylon macaques, the reproductive age is half as long - about 10 years. But researchers saw the main reason for the poor reproduction of Ceylon macaques not in this, but in the different survival rates of young females. 75-80 percent of female rhesus macaques, about 67 percent of female cynomolgus macaques, and only 15 percent of female Ceylon macaques survive to reproductive age.

Young female Ceylon macaques are at the very bottom of the hierarchy. Adults bully them and take away food (sometimes literally taking it out of their mouths), so that most of the females die in the first six months of life. As a result, although Ceylon macaques reproduce on average quite often, once every year and a half, their reproduction rate (the average number of daughters a female has during her life) was less than one - 0.9. While in cynomolgus and rhesus macaques the reproduction rate was 3.1 and 1.6-2, respectively.

The study authors conclude that changes in the social structure of ancient human ancestors and the emergence of monogamy seem to be the most likely reason for their reproductive success. Human communities did not have such a strict hierarchy as other primates, and this made it possible to reduce the mortality of young females, which, according to researchers, ensured population growth.

Researchers have also proposed other versions of the emergence of social monogamy. Thus, economist Gary Becker suggested that monogamous couples arose when it became important for a man to be sure of his paternity. Biologists from the University of Waterloo have shown using a computer model that ancient people may have switched to monogamy out of fear of sexually transmitted infections and under pressure from other members of the community who did not want to catch the infection. And ethologists from Cornell University suggested that males were forced to switch to monogamy because they could only protect one female and her offspring.

Ekaterina Rusakova

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