Science Forums 2

[CraigD]

Originally Posted by Boerseun

I agree with that, but discussing the origins of the idea that humans are supposedly monogamous, and whatever benefits upholding that pretension might have, is surely scientific.

Originally Posted by InfiniteNow

Sorry to have to disagree with you here, mate, but I do. Shouldn't one first prove there is a such thing as unicorns before they go on conjecturing about which chemical causes them to be different colors?

Humans are not monogamous

I disagree with several of the statements implied by these quotes.

First, when studying animal behavior, even that of members of the brainy, social, human species, studying our ideas – which, in this context, I think is more clearly termed our beliefs – about the behavior is complicated and problematic. It’s more effective, I think, to approach the subject empirically, defining and measuring the collection of behavior in questions. While even little experienced students of non-human animal behavior usually understand the importance of and strive to avoid anthropomorphizing the object of their study, students of human behavior need also to understand and avoid this source of bias, and attempt to study humans as just another animal species, as if the student was not of the same species.

Second, the analogy that studying monogamous behavior in humans, or any other animal, is like studying unicorns, is, I think, off. Animals don’t exhibit well-defined “unicorn-related behavior”, but various species do exhibit monogamous behaviors. A source of potential confusion is that there are several important behaviors to which the term “monogamous” applies – social, sexual, genetic, and marital, to name just those in the wikipedia article to which InfiniteNow linked. Some members of an animal populations, including humans, engage in various combinations of these behaviors at different times and circumstances in their lifetime.

So stating that humans are or are not monogamous is like stating that humans are or are not swimming, or some other inconstant behavior. Better, I think, to agree with the statement “some humans sometimes behave monogamously”, and seek a clear definition of what this means.

Toward this end, I propose that we adopt a “central dogma of human monogamy”, that is, a core area of empirical observation on which we can agree. Here’s my first draft, culled from various anthropologists and zoologists, especially Desmond Morris:

• The likelihood of children surviving to reach maturity and having offspring is increased by being protected by adults, and decreased by being attacked by adults.
• Usually, adults are more likely to protect, and less likely to attack, children they believe are their genetic offspring than those who are not.
• Because of an uninterrupted “chain of custody”, a mother is almost always certain if a child is hers.
• A man is certain that he is the father of a child only if he is certain that no other man had procreative sex with the mother during the period in which conception occurred.
• A man is certain that he is not the father of a child if he has not had sex with the mother during this period.

From these few assumptions, the rationale for a variety of behaviors are suggested:

• To assure that a man will protect her offspring, a woman will attempt to assure a man with whom she’s had sex that she has had sex with no other man.
• To assure that the child of a woman with whom he’s had sex is his, a man will attempt to assure that the woman has sex with no other man.
• To assure that many men will think they might be her child’s father, a woman will have sex with as many men as possible
• To assure that he has as many children as possible, a man will have sex with as many women as possible.
• To assure that another man who has had sex with a woman will protect her child, believing it his own, a man will attempt to keep his having sex with her secret

Throw on top of this list the biological trait of human females, unusual in the primate family, that it is difficult to determine when they are or are not able to conceive, and the species's great language and social skills, and you have a motivational basis for myriad, complicated, culturally-dependent confidence-winning, deception, suspicious and jealous behaviors. Whether you categorize the collection of these behaviors for a given culture or the whole of human kind as “primarily monogamous” or “primarily promiscuous”, or eschew such labels, these behaviors are clearly not simple.

An additional biological trait of human females, common among mammal species, is that breastfeeding greatly reduces the likelihood of conception, gives rise to a grim tendency in human male behavior. If a man is having sex with a woman with a young child he is certain or strongly suspects is not his own, he has a motive to stop her from breastfeeding it, by some means, so that he she can conceive his child. Even if the child is no longer breastfeeding, it requires resources that may be limited, and shared with children the man is confident are his. Thus, as in many mammal species, males are more likely to kill children than females, with stepchildren being at greatest risk.