Food For Sex?: An Evolutionary Psychologist On How Humans Came To Create Families

Food For Sex?: An Evolutionary Psychologist On How Humans Came To Create Families
Food For Sex?: An Evolutionary Psychologist On How Humans Came To Create Families

Video: Food For Sex?: An Evolutionary Psychologist On How Humans Came To Create Families

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Video: Evolutionary Psychology: An Introduction - Dr Diana Fleischman 2023, January

There are endless debates about the nature of the origin of the family: some are sure that the specific norms of life in marriage are "natural", and, therefore, obligatory for everyone. Others see any reference to human nature as an attempt to impose outdated patterns. The evolutionary psychologist Pascal Boyer, in his book "Anatomy of Human Communities", explains in detail how kinship developed in the course of natural selection in our distant ancestors. The changes that the human evolutionary branch has undergone over the past two million years explains modern approaches to reproduction, caring for children and the existence of social groups. This is a difficult story, because in the course of human development, several evolutionary processes took place simultaneously, strengthening or weakening each other.


To unravel these many causal relationships, let’s start with the emergence of the hunt. The gradual development of hunting has had a huge impact on human evolution, as it gave people the opportunity to eat better, providing them not only with more calories, but also fats and proteins, which are less in the composition of plants. Access to more varied food has allowed larger brains with more complex cognitive abilities to develop. Nutrition is critical here, as the brain requires more energy than any other organ.

The human brain of modern anatomical appearance is twice the size of the brain of the preceding Homo habilis.

But why did the brain become more complex? The establishment of social relationships is among the many factors. A sophisticated brain made it possible to track social connections, which facilitated more effective collaboration between people. In addition, a larger brain made hunting more effective, especially for large animals - deer, mammoths, the prey of which required hunters to collect and accumulate large amounts of information about the behavior of potential prey and develop joint techniques to overcome internal fears. A successful hunt provided nutrients that aided the development of the brain to hunt better. This is the first of many examples of positive feedback in the evolutionary process.

But a big brain also means a big head. Here natural selection ran into a physical barrier. Due to the device of the human pelvis, which allows us to move on two legs, the birth canal limits the size of the newborn's head. Of course, there are many possible evolutionary ways to overcome this problem. In fact, it all ended with the early homo giving birth to babies that were not fully matured, so to speak, not completely ready for life, so that they had time to be born before their heads became too big. This significantly limited the possibilities of people, since children appeared helpless and took a long time to reach a state of maturity. Weak offspring require significant parental support, in particular in the form of breastfeeding, so that for much of their adult life, women were either pregnant or lactating, which limited their participation in the hunt. But even after weaning, babies still need intense care and protection, which also limits women's ability to get food. However, all restrictions are compensated by the fact that with the advent of hunting, more nutritious food becomes available - meat.

Another positive feedback has arisen with the emergence of the practice of cooking: the use of fire destroyed the cell walls of plants, reduced their toxicity, and also softened the meat. It is likely that the combination of these factors accelerated the evolution of the brain, and not only due to the increase in the nutritional value of food, but also due to the fact that the need for its intensive digestion has decreased. As anthropologist Leslie Aiello suggested, the evolution of the brain and the digestive system are interconnected. The brain is a high-cost organ: accounting for only about 2% of body weight, it consumes about 20% of the body's total energy. An increase in this organ in early humans could only occur due to a decrease in energy consumption for an equally high-cost digestive system. Indeed, the intestines of modern humans are not as complex as those of other primates.

The helplessness of children has cost women dearly. Mutual aid helped partly.

As anthropologist Sarah Hrdee noted, breastfeeding has become somewhat of a group affair, as many women, both female relatives and non-female relatives, have had to look after and protect children together. Associated with this important evolutionary event was the emergence of menopause. Unlike other primates, females are able to outlive their fertile age for a long time - a feature that has long puzzled evolutionary biologists. Due to longer life and menopause, grandmothers appeared, that is, women who could invest more time and energy in raising grandchildren, and not have more children. The facts regarding the evolutionary role of menopause are not yet as clear as we would like, but this physiological innovation appears to have created another adaptation cycle. Young children demanded better protection, it took more energy for them, and mothers could provide them with all this, only with the additional help that allowed them to give birth to more helpless babies and feed them longer. A critical evolutionary change was the emergence of married couples, the close union between a man and a woman to bear and raise children. In all human communities, there are such stable predictable relationships between a man and a woman, which are characterized by a "monopoly" on sexual reproduction, joint investment in offspring, as well as unconditional mutual assistance and shared use of resources. And although all this is familiar to us, and precisely because it is familiar, we must remember how unusual this evolutionary behavior is. It is true that family happiness is not alien to pigeons - in fact, many birds form stable pairs for reproducing offspring - but taxonomically they are very far from us. In great apes, the closest relatives of humans, females forage for themselves and their young, and this is the same behavior in a wide variety of reproductive systems - from gorilla harems to promiscuous chimpanzee groups.

Human couples are unusual in other ways as well. First, their bond is often supported by a strong sense of affection or mutual attraction between the partners, as well as an intuitive sense of solidarity. Anthropologists have observed different forms of romantic affection and even passion in a wide variety of communities, so this kind of feeling is definitely not a "Western invention." The frequency with which love and marriage coincide varies greatly from place to place and, of course, depending on the particular marriage.

And yet a sense of common destiny, solidarity of partners is unique and distinguishes us from all other primates.

Secondly, a pair marriage, in addition to the two main participants, includes other people. For example, the union of Victoria and Albert creates social bonds between relatives of Victoria and Albert, as well as between relatives of Albert and Victoria.In other words, in the course of human evolution, not only married couples appeared, but also non-blood relatives. Indeed, in many human groups, parents and kin actually participate in the selection of suitable partners for lasting alliances - this is true of many hunter-gatherer tribes, all agricultural and many modern societies. This fact would have astounded a chimpanzee anthropologist to the core. Other species do not know any nonblood relatives.

Third, fathers are actively interested in their children and are emotionally attached to them, protect and take care of them. Fathers protect their children and provide them with resources, in many cultures they also play with them and have a widespread interest in their well-being for many years. The birth of a child greatly changes the father's motives and is reflected at the level of his neurophysiological and hormonal processes - fatherhood literally rebuilds the man's brain. These similarities in monogamous marriages are significant in light of the evolutionary positive feedbacks described above. Helpless children require great efforts on the part of their parents, and because of this, women are not able to obtain as much food as before the birth of the child. In such a situation, mothers who were able to guarantee themselves stable support from a man are in a better position compared to those who did not succeed.

Usually, the emergence of monogamy in humans was explained by a simple exchange, in which women offered men the opportunity (usually exclusive) of sex in exchange for a stable supply, in particular, that "expensive" high-calorie food, which women had fewer opportunities to obtain, such as meat. This model, originally dubbed "food for sex," has drawn a lot of criticism. Anthropologists have noted that hunting food is less important in the diet of modern hunter-gatherers. In addition, many of these communities have strict rules that oblige the hunter to share the prey with everyone, and therefore a woman can hardly expect special gifts from her man. Finally, the child needs nutrients all the time, and hunting prey is feasts from time to time. They seek to acquire a large animal for the sake of prestige rather than for the purpose of efficient food supply.

The family-building model, originally called food-for-sex, has received much criticism.

Perhaps this criticism is exaggerated. The return on hunting among modern hunter-gatherers is really small, but this is due to the fact that, under the pressure of developed agriculture, these peoples have been pushed into less productive areas. Moreover, the norms requiring hunters to share do not exclude favoritism at all. Many hunter-gatherer communities will still say that it is necessary to share with all members of the group, but individual preferences will affect the actual distribution of prey. Finally, it seems that meat was indeed the most important resource for our ancestors. Even if it provided only a small fraction of the required calories, the fats, proteins, and other nutrients needed for brain development were supplied with the meat.

In the ancient division of labor, there was an obvious economic rationality: both sexes invested more in what gave them a comparative advantage. Sure, women can (and sometimes do) hunt, but men are, on average, more productive hunters. Men can (and often do) collect and process food, but they are not more productive than women. Economic considerations suggest that a division of labor based on these factors will be beneficial to both parties. Naturally, this division did not require direct discussion from the parties.But couples who effectively shared responsibilities were more productive and therefore better suited. It is true, however, that the food-for-sex formula is a narrow and misleading description of this division of labor, because it’s not just about meat and not just about sex. The main thing that a man gave his partner was protection from other men. The well-being of women is always threatened by violence, abduction and especially infanticide - comparative data show that for females of many species, all these are real dangers. These dangers are also present in human communities due to competition between men for access to women, especially in the context of tribal wars, which typically involve the abduction of women from a hostile group (and can flare up because of this). In modern societies, other men also pose a significant threat to women, and protecting against them is considered part of a man's responsibilities as a couple.

In response, the woman provides the partner. But this is where the formula “food (or something else) in exchange for sex” misleads us, because sex is far from the only thing that a woman provides in this exchange, and this requires clarification. Male participation in stable monogamous unions was consolidated if it turned out to be an evolutionary advantage. Any investment in children, from protecting them from enemies to providing food and caring for the child, increases the fitness of the species as it increases the likelihood of offspring surviving. This is why parental investment is so great.

But here an unexpected obstacle may arise, namely, uncertainty about parenthood. Men cannot be sure that all the children presented to them are their own.

And the man who protects and provides for the children of another man is actually working against the transfer of his genetic material. Any genes that lead a man to such behavior can be expected to be excluded by selection. On the contrary, any genes that induce men to be selective in their parenting, to protect and help only those children who are more likely to be their own, will receive a selection advantage. And we see that in males of many species one can find signs of such preferences and the ability to determine paternity or increase its likelihood. People are no exception in this respect. Therefore, being in a stable couple changes the motivation of men - from a simple search for sexual contact to the desire to make sure that a woman is not looking for these contacts somewhere on the side, which, as we will see, can explain some aspects of dominance in gender relations. Excerpt provided for publication by Alpina Non-Fiction Publishing House.

Images: Lucas Cranach the Elder.

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