Is monogamy really that ‘natural’?

I had never really questioned the efficiency or stability of monogamous marriage system of ours before reading the article Why monogamy is natural by an Emory Law School professor, John Witte Jr. I always thought that faithful monogamy was the normal and standard pairing system that is just for everyone and prevents families from degenerating. However, I was not much convinced by the article’s reasoning, and actually became more suspicious about the nature of monogamy. I still think monogamy is the most fitting system, and personally I have never cheated even in my past ‘not-serious’ relationships, but the explanations of the article, which perhaps also include people’s common beliefs, looked quite questionable.

The first point was that “unlike most other animals, humans crave sex all the time.” With no further explanation, one can possibly infer that he was meaning that each member can have its designated mate when he/she needs it. However, being assigned with one mate for the rest of his/her life is only eliminating other possibilities outside the relationship. What if the married husband/wife does not want to be involved in sexual activities in a particular occasion? Of course, looking for another mate would mean another ‘opportunity cost’ as evolutionary biologists would say, but how much applicable is that to humans, especially females? These arising questions made the first argument somewhat seem like a reason why polygamy is natural.

The second reason was that “human babies are born weak, fragile, and utterly dependent for many years” and need help from both parents. However, chimpanzee society, which also has fragile infants with extended period of ‘child care’, raise their infants among their group members. Especially female members, together with the mother, take care of the young until it matures. Vast differences between human and chimpanzee do exist and would complicate the argument, but this counter example shows that monogamy is not the only solution for overcoming our vulnerability when young.

The third reason that “most fathers will bond and help with a child only if they are certain of their paternity” seems weak for supporting the argument ‘why monogamy [for humans] is natural.’ I am actually little curious if Brad Pitt will feel offended or really good about himself after hearing the quoted sentence. The author’s argument is quite true if we look at the example of infanticide shown by lions and some primate species who kill babies of other males upon taking over a new group. However human ethics are much more mature than that as shown by good adoption system. Adopting fathers are probably not the most fathers, but we do have many opposing examples of altruistic fathers who take care of children who are genetically not his.

The last point the author mentions is that “men have historically been more prone to extramarital sex than women.” This sentence, again, seems to say that polygamy is the ‘natural’ form of our relationship, at least for men, since extramarital sex would mean that the person’s instinctive desire, which should be ‘natural,’ was not satisfied by his marriage. The author also mentions in the same paragraph that “humans have the freedom and the capacity to engage in species-destructive behavior in pursuit of their own sexual gratification.” However, he is also inevitably saying that humans have the freedom and the capacity to engage in species-productive behavior against their own sexual gratification by submitting to the societal norm, monogamous marital system, which sounds little ‘unnatural’ now.

Polygamy in the history or some primitive societies of Africa or Asia are sometimes viewed as barbaric and looked down upon. However, isn’t something barbaric less artificial and closer to our unpolished nature? One of the readers of the article, ‘reformthesystem’ commented, “In English language, “naturally” is only a synonym for: of course, customarily; not absolutely.” I guess we would need to define the word, ‘natural’ in the first place in order to have a proper discussion of whether monogamy is natural or not. However, I arrived at my own conclusion that monogamy can sometimes be ‘unnatural’ for each individual, but would be ‘natural’ for the human society as a whole, in terms of promoting the stable environment for everybody.


Why monogamy is natural by John Witte Jr.

5 thoughts on “Is monogamy really that ‘natural’?

  1. I really appreciated reading this because we just read an article relating to your blog. In your last paragraph, you quoted a reader defining “natural” as customary- and that is the definition I would like to go with.

    I do believe that monogamy is natural. In fact, it has been proven in prairie voles (who are used as a model system because their social bonding is VERY similar to humans) through experiments done at Emory. It is likely that there are environmental factors involved, but it is also important to focus on two hormones: oxytocin (females) and vasopressin (males).

    Experiments show that injection of these hormones into the nucleus accumbens show an increased rate of partner preference formation. Partner preference formation is the same as loyalty to a partner over a stranger- I relate this to monogamy as it is a single partner at a time. This was proven with statistical significance and I believe the experiment is quite valid.

    As for the fourth paragraph where you mention fathers taking care of children that are not their own- this is an example of alloparenting (individuals other than the parents take on parental role). Generally with normal levels of vasopressin in males or oxytocin in females there would be a 50-50 chance whether they attack the pup or act as a parent towards the nonbiological pup. Only when these hormones are increased, would an increased rate of alloparenting occur. Evolutionarily, this makes sense. You wouldn’t want to waste your resources on strangers because that does allow you to reciprocate your genes- it decreases your fitness.

    This is the article done at Yerkes, Figures 1 and 2 explain the gist:

    I didn’t mean to scare you with the science, I was hoping you’d be less skeptical about monogamy after hearing about research discussing why it’s evolutionary to be monogamous. I could understand if you don’t quite see the relationship between humans and prairie voles- it seems like you were discussing the fact that humans have higher cortical functions and would be cognizant of the consequences of cheating.

    So I don’t know if I made my explanation of the article clear, but any thing you want to add/argue?

    • Thank you sumo, for the explanation about your article. I kind of knew about oxytocin’s role as a ‘love hormone’, but I didn’t know that vasopressin has much to do in relationships. I was also surprised by the fact that the rate of alloparenting could be affected by these hormones too.

      After briefly reading your article, I think the study is valid too. I still think monogamy is natural, and that there are numerous reasons how it became customary. I just wanted to point out the weaknesses or possible invalidities of Professor Witte’s article.

  2. Humint: outstanding analysis of Professor Witte’s article. I appreciate your close reading. I don’t think you can do it here because you are quoting from an online source, but when there are page numbers, remember to include them in your inter textual citation so that the reader can find where you got your evidence from. I would love to hear a response from you to sumo’s vole example seeing as how you are both biology majors. And lastly, great Brad Pitt reference. I didn’t getting at first, but then re-read and it made me smile.

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