Just wondering if there is evoanth suggesting hominids are monogamous creatures or monogomy just lies on the spectrum of dispositions?
In case you don’t feel like reading through the second EvoAnth (Colin, you’re meant to capitalise it) post in two days I’m just going to give you the answer right now: the latter. There’s nothing which suggests that humans are meant to be monogamous.
This is true regardless of what perspective you view it from. For starters you could play the numbers game. Whilst most people today are monogamous this is due to the success of a handful of pro-monogamy cultures. As such you couldn’t really tell if monogamy was typical or there are just large a-typical cultures distorting the results. Europe and the USA, for example, make up over 1/7 of the worlds population and are almost completely monogamous (as in the people inside it are, not those two regions only love each other). Thus they could distort the results of any “head-count” quite considerably.
A better way to count it is to make all societies equal and measure how many societies are monogamous rather than how many individuals. When you count it like that you wind up with 85% of human societies practising polygamy of some description, so monogamy is far from the norm for our species. Indeed, 85% is the number for polygyny (one man having multiple wives) rather than polygamy as a whole. Polyandry (when women are the lucky ones) is rarer, granted, but still exists. As such 85% is a low-end number.
Alternatively you could look at it biologically. Perhaps we have some hormone that prompts lovey-dovey feelings, but only when exposed to the same individual. Surely that would be a pretty sure indication that hominins are meant to be monogamous. Of course if such a thing were discovered I’m not sure whether it could be used to demonise non-monogamous people. Being different isn’t something we should be automatically intolerant of, especially if that is the product of their biology.
However, my caveats against discrimination are somewhat moot given that we have yet to find this lovey-dovey hormone which only responds to a single individual. Neurobiologists are aware of a range of hormones associated with affection and attachment in relationships (although they still don’t have the complete picture). These include vasopressin and oxytocin (the famous “cuddle hormone“) which are released during intimacy and work with the dopamine system to make bonding with someone a rewarding experience (dopamine being the brains reward system).
There’s also testosterone (whose involvement people don’t know much about) and several others, including serotonin. This chemical appears to be associated with happiness, yet contrary to what you might expect it actually decreases during the early stages of a relationship. This may be associated with how you idealise a partner during those early days. Such a decrease is also associated with OCD, leading to the amusing quote from the aforelinked paper.
Indeed, early stages of romantic love show similarities to OCD, including symptoms of anxiety, stress, and obtrusive thinking….although we should keep in mind that OCD is a Diagnostic and Statistical Manual of Mental Disorders version IV (DSM-IV) disorder and the early stage of romantic love is not.
Again, there’s nothing about any of these hormones that limits them to only applying to only one individual. Serotonin, for example, is also linked with food consumption yet you can enjoy two dishes. Oxytocin is also associated with breast feeding yet a mother can love two children. There’s no need to limit these chemicals to only allowing monogamous relationships.
That said, some studies have been done which show a relationship between monogamy and oxytocin in voles. However, these aren’t comparing monogamy with polygamy but whether a monogamous vole will have an “affair” (it won’t if it has more oxytocin) or they reveal that a monogamous species has more oxytocin receptors than a species which has more “affairs.” In other words they’re measuring monogamy versus promiscuity rather than monogamy versus polygamy. As such they can’t really applied to this situation and so the presence of oxytocin does not mean humans are meant to be monogamous.
So there you have it. Humans aren’t supposed to be mongoamous. However, that shouldn’t be construed to suggest we are meant to be polgyamous. Instead these are just both parts of the wide spectrum of human mating strategies. Neither are really “correct” any more than a particular hair colour is right. It’s just natural human variation.
|A. de Boer, E.M. van Buel, G.J. Ter Horst (2012). Love is more than just a kiss: a neurobiological perspective on love and affection Neuroscience, 201, 114-124 DOI: 10.1016/j.neuroscience.2011.11.017|
|Henrich J, Boyd R, & Richerson PJ (2012). The puzzle of monogamous marriage. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 367 (1589), 657-69 PMID: 22271782|
|THOMAS R. INSEL, LAWRENCE E. SHAPIRO (1992). Oxytocin receptor distribution reflects social organization in monogamous and polygamous voles Proceedings of the National Academy of Sciences, 89, 5981-5984 DOI: 10.1073/pnas.89.13.5981|
|Ophir AG, Gessel A, Zheng DJ, & Phelps SM (2012). Oxytocin receptor density is associated with male mating tactics and social monogamy. Hormones and behavior, 61 (3), 445-53 PMID: 22285648|