Part 1. Humans are (Blank) -ogamous

(A)s our forebears adopted life on the dangerous ground, pair-bonding became imperative for females and practical for males. And monogamy – the human habit of forming a pair-bond with one individual at a time – evolved.” (Helen Fisher 2004: 131)

Several types of evidence suggest our pre-agricultural (prehistoric) ancestors lived in groups where most mature individuals would have had several ongoing sexual relationships at any given time. Though often casual, these relationships were not random or meaningless. Quite the opposite: they reinforced crucial social ties holding these highly interdependent communities together.” (Chris Ryan & Cacilda Jethá 2010: 9-10)

 “We are not a classic pair-bonded species. We are not a polygamous, tournament species either…. What we are, officially, … is a tragically confused species.” (Robert Sapolsky)



The above three quotations were selected to illustrate the range of views that exist on the evolution of human sexual and mating behavior. This is not a trivial matter. To primatologist Bernard Chapais: “The central puzzle of human social evolution… is to explain how promiscuity was replaced by the pair bond” (that is, assuming the pair-bond has gained complete ascendancy). But it’s about more than our ancestors’ mating behaviors. Lurking in the background is the notion that our ancestral behavioral patterns impact current ones, via phylogenetic inertia. Additionally, how we view the past is important because, rightly or wrongly, we have a tendency to associate what is natural with what is good (but note well the naturalistic fallacy). For both of these reasons, the past matters.

This is obviously a sensitive topic that goes beyond academic esoterica, so it is important to tread softly. But it is also necessary to confront the facts. Heterosexual monogamy remains the dominant, privileged model in Western societies. However, with sex scandals in the news recently (and… always), and with popular books and articles asking whether monogamy is obsolete, a myth, fettered by unrealistic expectations,or in need of amending, it is understandable that people would wonder how ‘natural’ it is. 

To begin, let me say that I side with Sapolsky. Individuals may figure out what works best for themselves in terms of balancing sex, love, intimacy, and commitment, but collectively we are a tragically confused species. The signposts in our biology and behavior suggest as much. This seems to originate from a few places: our evolutionary past, the overlapping – but independent – drives for love, sex and reproduction, individual variation in sexual preferences and drives, and the powerful effect of culture. One would think, given the importance of sex and mating in evolution, that natural selection would have put a straight-jacket on it and given us a stricter blueprint to follow, as other species seem to have. That doesn’t seem to be the case, however.

Humans are said to have an inclination for homogamy (mating with people from the same ethnic or sociocultural background), and exogamy, where one sex leaves the natal group to find potential mates (evidence from 2 million year-old teeth suggests that, like chimpanzees, Australopithecine females were the ones to leave). But biology is the science of trends and exceptions, not laws. Across the spectrum of human cultures, we can find examples of heterogamy, endogamy, polyandry, polygyny, monogamy, non-monogamy, polyamory, and so on. However, these do not all occur in equal frequencies, so I don’t think we are truly “blank-ogamous.” There is also lots of room for variation within each culture. Being good Popperians committed to the principle of falsifiability, it is probably easier to say what we are not than what we are. One thing is clear: we are not simple.

It must seem audacious to presume to know anything about the sexual and mating behavior of our ancestors. Interpreting the past is tricky because behavior does not fossilize well, and outside of time travel we cannot observe this directly. However, researchers can utilize clues from many fields – cultural anthropology, paleoanthropology, anatomy, genetics, psychology, primatology, neuroscience – to place the pieces of the puzzle on the table to see what the big picture looks like. And the pieces are fascinating. 

A few qualifiers at the outset: I am a biological anthropologist, but this topic is not my specialty so I’m not claiming this will be comprehensive or conclusive. I’m writing this because, from my reading of things, there are good arguments on both sides for humans being pair-bonded with the ability to love deeply, though with a penchant for promiscuity. Trying to synthesize those two arguments is proving quite difficult, which I suppose makes me just another confused member of our species. It probably says something that I actually found it easier to write about the meaning of life. Due to the complexity of the topic, I decided to break this up into a series of posts (still in the works), roughly divided into the evidence for promiscuity in our species, the evidence for pair-bonding, and a synthesis of the two. Each post is probably too long, and in bullet-point style (as my advisor at Binghamton, Mike Little, used to say: “when in doubt, make a list”). I’m not completely satisfied with what I’ve compiled so far, but I am still learning.


  1. Part 1. Introduction Link
  2. Part 2. Promiscuity Link
  3. Part 3. Promiscuity (Genetics) Link
  4. Part 4. Promiscuity (Anatomy/Physiology) Link
  5. Part 5. Pair-Bonding and Romantic Love Link
  6. Part 6. Many Intimate Relationships Link
  7. Part 7. Is It Possible to Love Two People? Link
  8. Part 8. Love and Suffering Link
  9. Part 9. Love Is an Evolutionary Compromise  Link
  10. Part 10. Wondrously Complex Paleo-Sex Link
  11. Part 11. Sexaptation: The Many Functions of Sex Link
  12. Part 12. A Tripartite Conundrum Link
  13. Part 13. Is Monogamy ‘Natural’? Link
  14. Part 14. Paleo Hookups and Archaic Lovers Link
  15. Part 15. Lessons from Models of Sex and Love Link
  16. Related: Erotic Laundry Lists Link
  17. Related: Did Pair Bonds Evolve to Be Asymmetrical? Link
  18. Related: Evelyn’s Story Link


Fisher H. 2004. Why We Love: The Nature and Chemistry of Romantic Love. Putnam. (Link )

Ryan C, Jethá C. 2010. Sex at Dawn: The Prehistoric Origins of Modern Sexuality. Harper. (Link)

Sapolsky R. This quote comes from a lecture series titled “Biology and Human Behavior,” found here (see lecture 11). It was too good not to use.

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11 thoughts on “Part 1. Humans are (Blank) -ogamous

  1. Pingback: The Myth of Monogamous Pair-Bonding | Among Others

  2. Just a minor point about Chapais’ quote since it’s not that clear neither here nor in the NYT article. By pair-bonding, he doesn’t mean strict monogamy as seen, for example, in gibbons. He uses it to differentiate both from promiscuity and monogamy. For pair-bonding to occur, preferential relations between partners are required but in this sense, both serial monogamy and polygyny (and the much rarer polyandry) fit the bill.

    • Thank you for the clarification. That does help my understanding of things. I wonder if something such as consortships (in chimpanzees or other species) would fall under this. Or are they too brief in duration to count as pair-bonded?

  3. That’s a good question. I’m really no expert on this but consortships cause problems of their own kind to begin with. Their duration vary greatly from a few hours to a days and the name itself is used in a variety of ways (1). Furthermore, it’s not clear if it is really or always efficient as a method of mate-guarding because the timing of copulations is important and in many species, females manage to copulate with other males as well (2).

    To come back to Chapais, I wouldn’t want to put words in his mouth so I won’t! But according to his chapter in Kappeler and Silk, which is kind of a brief exposé of his book’s main thesis, he is talking about a multifamily structure which requires stable breeding bonds. His model rests in part on Lévi-Strauss’ reciprocal exogamy model. Contrary to chimpanzees, who live with their kins but mainly don’t recognize them, humans’ kinship is visible because of the pair-bond and it’s correlate : fatherhood. Hence the recognition of agnatic kins which are already present but unknown since the mechanism for this rests on enhanced, or disproportionate familiarity, between a few individuals (I really simplify here so don’t throw rocks if it’s not completely accurate!). (3)

    In this light, I’d say that Chapais doesn’t include consortships in his definition of pair-bond but I couldn’t say if it is an absolute position or if it is only in the context of his model which tries to explain the human community structure. And as Small wrote, consortships could be precursors to more stable pair-bonds.

    (1) Manson, J. H. (1997). Primate Consortships: A Critical Review. Current Anthropology, 38(3), 353-374.
    (2) Small, M. F. (1990). Consortships and conceptions in captive rhesus macaques (Macaca mulatta). Primates, 31(3), 339-350. doi:10.1007/BF02381105
    (3) Chapais, B. (2010). The deep structure of human society: Primate origins and evolution. in Mind the gap: Tracing the origins of human universals, 19.

  4. Pingback: Sex at Dawn and Science « Yes to Connection Blog

  5. Pingback: Humans are not ‘blank’-ogamous | Fieldnotes & Footnotes

  6. Pingback: Patrick Clarkin’s Humans are (blank)-ogamous Series | Welcome to the EvoS Consortium!

  7. Pingback: Part 7. Humans are (Blank) -ogamous: Is It Possible to Love More than One Person? (Poll) « Patrick F. Clarkin, Ph.D.

  8. An extremely engaging topic. I have a mind like a garbage disposal unit, it chews up everything, the sole criterion being that it must be interesting. On the subject of polygamy in humans, and I mention that the president of my country has six wives and twenty legitimate children: polygamy appears to arise when there is a shortage of males who qualify as mates. This could be in societies where it takes a male so long to accumulate sufficient wealth to support a family, or in warlike societies where the males are getting killed off often and early in life. The famous examples are the Jewish patriarchs Solomon and David. Those ancient Israeli men spent a lot of time in battle with its attending high mortality. In addition, when they conquered a rival tribe, all its males would be slaughtered while women and livestock were “acquired.” (Please excuse the scarequotes.) For a female of the time, losing her male owner was a death sentence as she had no legal rights to shelter or the means of livelihood: all the deceased male’s assets went to his male kin. The king became the husband of last resort, marrying women whose husbands and fathers he had sent to die in battle. Naturally he may have bedded the more nubile of his wives as well. If you read the Fourth Surah of the Koran you’ll note the obligation on a man to marry the widow of his brother in order to rescue her from exactly the same situation: he has a duty to marry as many women as he can support. In my country, polygamy started out as a military necessity but its continuing popularity is for financial reasons. Indeed the senior wife may insist that her husband marry again. In a rural setting without electricity or running water, extra wives in a household can share the onerous work.

    I’m looking forward to reading the rest of the series and hope that you have avoided the Skinnerist trap so common in these studies.

  9. Pingback: Monogam, Polygam, oder ...gam?

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