Humans are naturally monogamous
The lives of celebrities, politicians and other prominent people have constantly fed society’s ample appetite for juicy gossips. News, particularly of tabloid material has constantly bombarded our consciousness and has even seeped into the lives of ordinary men and women that the word monogamy is fast becoming unknown.
Scientists are attempting to explain how humans socially relate with other humans, whether man is naturally monogamous or polygamous. Studies have based their conclusions mainly by focusing on the behaviour of animals.
The practice of monogamy can be seen in the animal kingdom, and it has been found that birds far exceed its practice — scoring more than 90 percent compared to mammals with only 7 percent.
In the context of scientific study, an animal that engage with only one pair to raise up their young despite having sexual relations with another is still enclosed within the definition of social monogamy. Hence, a spouse who pursues extramarital affairs but still continues to live and raise the family is still regarded as socially monogamous.
This differs from sexually monogamous creatures that avails itself exclusively with one partner and has been observed to be extremely uncommon among animals.
Further from this description, the scientific field do not have a clear cut explanation for monogamy. There is great debate as to the natural inclination of man — whether it is naturally monogamous or polygamous. A closer look into its respective practice among animals and human society, as well as the factors which could be responsible for either behaviour is in order and thus, attempt for greater comprehension on the subject.
II. Monogamy Among Non-Human Primates
Five different types of sexual strategies had been observed to be exhibited among non-human primates. One is collective in type, comprising of a number of male and female primates, raising together their dependent young. The multiple pairing had been found among macaques and chimpanzees.
Another type, the most common strategy involves one male forming multiple bonding with several females and raising all the young. Multiple pairing is practiced among gorillas and spider monkeys.
A different approach is the monogamous pair. Compared to the other four types, monogamy has been seen as extremely rare in the animal kingdom. Gibbons, titis, owl monkeys are one of the few primates that have monogamous pair. Dual participation in raising their young is one of the aspects that are quite unique to this kind of pairing, in addition to pair bonding between the male and female primate. Pair bonding though, most often do not last a lifetime nor does mating apply exclusively to their current partner. Titi monkeys fall under this category while certain species of gibbons significantly differ by practicing sexual loyalty to their pair bond and stay committed for life. Gibbons tend to spend time and maintain close proximity with their social partners (Mason 1966: 23).
III. Biological Explanation
Towards the turn of the century, the field of neuroscience had gained more insight into various brain processing. One of which includes the discovery of a group of genes that play an important role in the development for normal brain functioning. No matter how far reaching scientific research has progressed on these subjects, the science of neurobiology however, can shed little light for understanding the biological explanation of emotional bond.
The study of emotion is quite complex and covers a wide range of expression. Although studies on aggression or the neural effect of loss and separation is not deficient in scientific literature, very few had delved into the area on the emotion that bonds two creatures.
This does not mean however, that there is a total absence of scientific literature on the matter, but pertaining to research on emotional ties or attachment is quite deficient. Reason for this lack, can be blamed on the inadequate scientific definition of what emotional attachment is that binds commitment between mates. There is also the dilemma of how to biologically differentiate between fleeting attractions and one which carries strong commitment. Whether it is referred as attachment, pair bond or love, our society recognizes the beauty of such an experience. However, it is not quantifiable that can easily be measured under rigid control in the laboratory. Moreover, the emotion that spurs human pair bond cannot be fully replicated by studying the behaviour of animals. Strong maternal devotion had been exhibited by animals, particularly that of rats, among their young. Nonetheless, they are not discriminating in showing their affection. Care and devotion is not exclusively given to their own brood but is generally shown to other young rats placed near them.
Hormonal and Gene Influence
In studying two kinds of rodents, prairie and montane voles, neurobiologists have found significant difference in the behaviour of mate preference through the observation of differences in brain structure and chemical composition.
Studied in their natural habitat, prairie voles live with a single breeding partner often staying committed for life. Even upon the death of their mate, majority of these voles reject to have another breeding mate. It appears that prairie voles develop attachment to an unrelated male consequently after mating. Mating plays a crucial role in the progression of mate selection and preference.
Montane voles, related specie of the prairie vole display an apparent contrast in sexual approach. Montane voles do not exhibit any inclinations to form significant pair bonding. Male montane voles do not even play an active role in rearing their young. They neither develop any preference to form commitment with a mate even after mating but they are rather more inclined to live in seclusion in their own burrow.
Due to the noticeable difference between these two closely related species, scientists are looking for explanations to these differences in social behaviour through the examination of the chemical brain activity and structure. For now, researchers are pinning down on the presence of oxytocin (OT) and vasopressin (AVP), coupled with how these neuropeptides are transmitted, as the factors affecting the complex social behaviour of monogamous and polygamous activities. The participation of OT in brain activities had been present during giving of birth and reproduction of milk, thus OT helps to foster ‘maternal instincts’. Laboratory studies have zeroed in on OT as the sole neuropeptide to have direct causality over developing attachment even among non-monogamous creatures. The release of OT during mating is seen to have an effect in developing partner preference and bonding. Even laboratory manipulations wherein the release of OT was induced while a female prairie vole was exposed with close proximity with a male vole; attachment was developed even with the absence of copulation. It must be recalled that in the natural setting, mating was a crucial role in the release of OT and the preference for a mate. To further reinforce these findings, during mating, females were treated with a blocker for OT. These female voles significantly did not build attachment to their sexual partner. It would appear that OT is one of the most significant factors that affect the behaviour of choosing and developing attachment particularly among females of this specie.
However, the same neuropeptide do not seem to have the same effect among its male. AVP among male voles are linked to aggressive and territorial behaviour (Ferris 1992: 212). Just as the inducement of OT among females produced pair bonding preferences, inducement of AVP and exposure to a female among male prairie vole even without mating caused attachment with the female. Blocking of AVP during copulation caused the failure of the progression towards making a preference for a partner. The absence through blocking of AVP among males also inhibited the formation of paternal behaviour.
The same application and manipulation had been done to the montane voles that were naturally polygamous. Conversely, the same application did not create the same effect of developing pair bonding, either male or female montane voles. This seeming dissimilar effect of OT and AVP among differing species also shows the role of brain structure in such behaviour.
Although both voles have OT and AVP, they differ in where these hormones are transmitted through the receptors by which these peptides pass through. Prairie and montane voles have mark difference in the pathway in which these hormones are distributed. OT and AVP activate regions in the brain of prairie voles that promote bonding behaviour while brain receptors in montane voles are activated in regions associated with non-social actions, hence the behaviour difference. Therefore, the formation or lack of pair bonding do not simply depend on the amount of OT and AVP but the anatomy of its neural pathways in which it travels and the area of the brain it is targeted to activate.
Among humans though, there is little scientific knowledge as to how behavioural pattern of pair bonding is shaped. Like the voles, OT and AVP are also present among humans and are released during mating. It is not clear though, whether monogamous or polygamous tendencies are dictated by differences displayed among prairie and montane voles replicates the same condition among different individuals (Insel &Young 2007).
In a related study conducted by a Swedish scientist the gene coding of over 552 respondents involved in heterosexual relationships were investigated. The amount of Gene RS3 334 among men has been seen as responsible for influencing how they form attachment with their partners. It is possible that men can have an absence of RS3 334, or one can also have one to two of the said gene. The study’s findings revealed that the more RS3 334 that a man possesses, the more likely it will experience poor bonding. Having the maximum amount of RS3 334 displayed a lack of commitment thereby increasing the likelihood of staying “unattached” or given that they enter marriage, have the greater tendency to have poor marital relations compared with those who had one or none of the gene (Shetty 2008).
Despite these revolutionary scientific findings, bioethicists warns the public that caution should still be in place before the fidelity or infidelity of partners be totally be blamed or excused by a single gene or hormone. Human relationships are enclosed within a myriad of factors (Keim 2008).
IV. The Issue of Monogamous and Polygamous Bonding in Humans
Transcending from animal to human behaviour, many would rather conclude that even man are not naturally inclined to be monogamous. Like the primates, two forms are readily observable in society. Of the two types of marriage systems, polygamy (plural marriage) has been found to be the most common throughout history than its opposite form of monogamy. Polygamy has taken two forms: polyandra, in which a wife has two or more husbands; and polygyny, in which a man has two or more wives. This second form of plural marriage has been much more common, historically, than the first, and still is, although polyandry still persisted towards the early 20th century in parts of India, on the high plateau of Tibet, and in other scattered localities.
Primary reason for its practice mainly falls out of necessity. Sustenance depends from a limited number of farmland and the careful balancing of population against food reserves. Each family therefore, avoids dividing its meagre tillage in ever-diminishing lots among its progeny by having the younger sons share the wife of the eldest son. Not only does this practice reduce the number of children in each generation, and keep each property permanently within the family, it has some other curious results.
Polyandry, for some reason not wholly accounted for by anthropologists, reduces the fertility of wives, and produces an abnormal ratio of male to female births. Custom obliges them to treat each husband with equal favour, but it often happens that a woman of many husbands may prefer one brother to all the others. Due to contacts with dwellers outside their village, women are feeling the stigma of polyandra. More women from this system then, are beginning to revolt and are asserting their own demands for monogamy (India: Too Many Husbands 1955: 41). Such social pressures are absent among non-human primates and thus, there are little chances of evolving towards monogamy.
The Moslem religion sanctions polygyny, four wives being permitted the male, according to the religious creed. China’s early history has always had its system of concubines. Much of Africa practices polygyny. Historically, most people practiced polygyny with concubinage as an integral part of the marriage-family system. The concubine is considered a wife with inferior status.
Polygamy is accompanied by a series of attitudes, roles, and statuses making it socially possible and appropriate, just as is monogamy. In East Africa the wife (cattle and goats are the coin used) to help her with the farm work. If he fails to increase his wives as his cattle increase, existing wives felt mistreated. More wives mean more rest for the older wife, as the younger ones can grub the brush, plant the corn and tend it against jungle beasts.
Place the attitudes of the current monogamous wife in our society in this setting, and they will not fit at all. She sees in such an arrangement only jealousy between women, quarrelling, and perhaps a little hair pulling. But wives fit into polygamous settings, just as do husbands into polyandrous settings, if the institutional forms demand it. A Chinese concubine revealed attitudes of this family system. She was married to a man as his concubine and bore him a child. On conversion to Christianity she learned of its monogamous requirements. She was left with a great predicament: leaving her status as a concubine and follow the dictates of her newfound faith which would incur social ostracism even from her own family. She also faces the difficulty of how to fend for herself and her son since she is used to being provided for everything she has need of by the husband. Another choice would be, to maintain the status quo and live with lifelong guilt (Leynse 1937:191-92).
As the Western pattern becomes known to women in polygamous cultures, there is increasing revolt. Take Pakistan, which is rapidly borrowing Western education and other Western practices. The feminist movement calls for the cessation of polygamy.
While plural marriage is still the approved marriage form in most densely populated areas of the world, and is today the dominant type, as cultures and peoples go, most couples remain monogamous even within polygamous societies. Most marriages in the world are, therefore, pair marriages.
Only 16 percent of societies across the world claimed to be monogamous. However, only 16 percent of the men among the non-monogamous societies did truly have more than one wife. Conversely, the study showed in these various societies that among the 16 percent so-called monogamous society had men and women acknowledged being involved with more than one sexual partner, other than the spouse.
It would seem that the aforementioned studies above in both the animal kingdom and human societies had brought a voluminous account of polygamous practices, which tends to lead to the conclusion that humans are naturally polygamous, a fact which many had already accepted as true.
Nevertheless, there is a strong factor which plays a key role of fostering monogamous inclinations among humans, which is the complimentary role that a man and woman contribute in rearing their children. The most overriding reason for man’s natural tendency towards monogamy entails the nurturing of offspring. In humans, all three individual members of the symbiotic trinity of mother-father-child are affected.
It is easier to see that there is increasing dependency in evolutionary sequence, together with increasing maternal care and more prolonged suckling. The reason that the newborn baby may commit more of its birth-weight to the human specialty, brain, and relatively less to a largely helpless body, is precisely that it enjoys this protected dependency and fostering by the mother — for the body is much more mature in other non-primate newborn, for example the colt, the most important and conspicuous trait of which is the different equine specialization in long legs at birth. In humans, the disproportionate parts of an infant’s body demands more of maternal care and the whole emotional pattern of greater closeness in the mother-child bond has ultimate effects upon the more intense inter-individual bond between the sexes.
Indeed, it seems probable that the specialization in maternity and in infancy, so to speak, of two members of the trinity would not be possible unless the sexually bound male were increasingly protective of the family. Homo sapiens are, strictly speaking, a domesticated animal; and domestication is defined as special protection from wild enemies, and special provision of food. The child could not therefore increase its dependency without being met by increasing nurture of the mother; but in turn, the mother could not increase her domesticated sexual dimorphism for this purpose without the protective attendance of the male; but the male increases his attendance upon the female because of inter-individual (sexual) drive. The full adult social state in all societies is a procreative membership in a biological family — not necessarily monogamous, not necessarily lifelong in duration, but nevertheless a condition toward which all adult human animals permanently strive. Therefore, human parents invest more on rearing their young compared to any other animals (Are Humans Meant to be Monogamous? 2008).
There is also ample evidence that sexual competition in polygamous set-up is disruptive (Wrong & Gracey 1968:55) which also help to promote monogamy. But the strong emotional striving could be motivated by sexual love, or which others interpret such intense feelings now commonly labelled as “romance”. Highly influenced by today’s fiction, drama, and movies, the latter is upheld as the center on the emotional relation between partners. In general, romance is accepted as having occurred when partners feel that they had chosen each other freely. Whether the choice is really “free” is not only beyond proof but from the perspective of the social scientist, it is totally irrelevant as to whether man’s will is really “free”. It is the actor’s sense or feeling of being free to choose that matters.
Man is neither a fallen angel who has lost his morals nor a reformed ape that has given up his “lower” nature and has somehow risen “above” the mammalian dispensation. Man has not ditched his mammalian inheritance. On the contrary, he has invested and built his evolutionary future ever more solidly upon it. The human female is plainly neither avian nor egg-laying: the human female is in every significant respect exuberantly more mammalian than any other mammal. Among mammalian infants, the human infant is as extravagantly infantile as they come. And among male animals, the human male is, without doubt, the best mammal in the business. In these circumstances, with the father coming home to stay, it is clearly the inescapable predicament of Homo sapiens to become human.
1. Mason, W. A. (1966). Social Organization of the South American Monkey, Callicebus moloch: A Preliminary Report, Tulane Stud. Zoology
2. Feris, C. 1992. Role of Vasopressin in Aggressive and Dominant/Subordinate Behaviours. New York: New Pork Academy of Science Press
3. Insel, T.R. & Young, L.J. 2007. The Tie that Bond: The Molecular Basis of Monogamy. Science and Spirit. Available at http://www.science-spirit.org/article_detail.php?article_id=190
4. Shetty, P. 2008. Monogamy Gene Found in People. NewScientist. Available at http://www.newscientist.com/article/dn14641-monogamy-gene-found-in-people.html?DCMP=ILC-hmts&nsref=news2_head_dn14641
5. Keim, B. 2008. Male Monogamy Gene? Not So Fast. Wired Science. Available at http://blog.wired.com/wiredscience/2008/09/male-monogamy-g.html
6. India: Too Many Husbands. Time, 1955. Time, Inc.
7. Leynse, P.J. 1937. A Chinese Concubine Tells Her Story. Review of the World. N.J: Prentice-Hall, Inc.
8. Wrong, D.H. & Gracey, H.L. 1968. Man’s Animal Nature: Continuities Between the Human and the Animal. New York: Macmillan Company
9. Are Humans Meant to be Monogamous? Available at http://www.chinadaily.net/world/2008-03/20/content_6552096.htm
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