Pair Bonding & Ritual Marriage

Over the past few years, something like a perfect storm has been brewing over human pair bonding and the profound impacts it has wrought on human social structure. This is a welcome development in a field that has long been dominated by those who wish to root the relatively modern idea of marriage in ancient evolutionary soil. Such a desire usually stems from the notion, metaphysical in nature, that marriage is a timeless and sacred institution. Given this animating impulse, much of the evolutionary literature on pair bonding and “marriage” has been a fact and fossil free zone where just about anything goes, and what goes usually serves the sub rosa interests of institutionalized religions. This has begun to change.

In 2008, Bernard Chapais published Primeval Kinship: How Pair-Bonding Gave Birth to Human Society. Chapais observes that primate sexual practices limit the recognition of kinship. When kinship is recognized, it does not extend far. This in turn constrains group size, composition, and alliances. Humans are obviously different, but how did it happen? Commenting on a recent study of hunter-gatherer group composition and kinship that appeared in Science, Chapais explains:

A key event might have been the advent of pair bonding in the human lineage. Our closest relatives, chimpanzees and bonobos, live in large mixed-sex groups [and] mate promiscuously, with both sexes having multiple short-term partners. [This results in a genealogical structure that] is to a large extent “socially silent.” Now suppose that pair bonding evolved in this type of social structure. This brought the multifamily composition of human groups, with enduring associations between mothers and fathers enabling children to recognize their fathers. This, in turn, made it possible for children to recognize their father’s relatives; that is, pair bonding would reveal the underlying genealogical structure and create bilateral kinship.

In the nascent “tribe,” males were now able to circulate freely between groups in which they had kin and in-laws, cross-sex kin maintained lifetime bonds, and between group alliances were ensured by kinship bonds, “marital” ties, and the ensuing extensive networks of bonds between in-laws. [T]he dramatic and fortuitous extension of kin recognition brought about by pair bonding would have launched the evolution of supragroup social structures in which a large proportion of individuals were now distantly related.

Pair bonding, in other words, triggered a cascade of kinship effects that irrevocably altered human social structure. Groups would have become larger, more cooperative, and more cohesive. Networks resulting from pair bonding and bilateral kinship would have enabled between group cooperation and “multilevel alliance structures.” These effects are mathematically unassailable and ethnographically observed.

Chapais was not, however, the first to suggest that pair bonding is a key hominid adaptation. In his 1981 article “The Origin of Man,” C. Owen Lovejoy proposed that pair bonding was the “breakthrough” adaptation for hominids. While intriguing, Lovejoy’s hypothesis was largely referential (depending heavily on primate models) and theoretical (grounded extensively in life history analytics). It was short on evidence, whether from fossils or people. Three decades later, there is now some evidence from both.

In 2009, Lovejoy was part of the team that unveiled the 4.4 million year old Ardipithecus ramidus or “Ardi” in a special issue of Science. The team argued that Ardipithecus is an ancestral hominid and the genus that spawned Australopithecus (which in turn led to Homo). Lovejoy’s contribution, “Reexamining Human Origins in Light of Ardipithecus ramidus,” re-states his case for pair bonding as a breakthrough adaptation and places it within a suite of adaptations that uniquely altered the course of hominid evolution. It is a densely packed and impressive argument that hangs primarily on the slender thread of canine reduction in Ardipithecus.

Although Lovejoy’s paean to proto-marriage has the distinct feel of an umbrella hypothesis, this does not make it untrue. In fact, the recent study of hunter-gatherer group composition by Kim Hill and colleagues provides additional support for the idea that pair bonding is the key to extended kinship. While we currently have no way of knowing when hominids began pair bonding, there seems to be little doubt that it played a critical role in human evolution.

Given this fact, it is not surprising that nearly all organized religions target and sanctify this key evolutionary adaptation. It is important to realize, however, that the pair bond has not always been subject to supernatural sanction or ritual blessing. In many pre-state societies where shamanic practices prevail, pair bonding or “marriage” is a rather low key affair detached from the spirit world. Hunter-gatherers “marry” and “divorce” with relative ease and without the kinds of rituals or covenants that arose in conjunction with the earliest organized religions. The metaphysics of modern marriage are a post-Neolithic invention.


Chapais, B. (2011). The Deep Social Structure of Humankind. Science, 331 (6022), 1276-1277 DOI: 10.1126/science.1203281

Hill, K., Walker, R., Bozicevic, M., Eder, J., Headland, T., Hewlett, B., Hurtado, A., Marlowe, F., Wiessner, P., & Wood, B. (2011). Co-Residence Patterns in Hunter-Gatherer Societies Show Unique Human Social Structure. Science, 331 (6022), 1286-1289 DOI: 10.1126/science.1199071

Lovejoy, C. (1981). The Origin of Man. Science, 211 (4480), 341-350 DOI: 10.1126/science.211.4480.341

Lovejoy, C. (2009). Reexamining Human Origins in Light of Ardipithecus ramidus. Science, 326 (5949), 74-74 DOI: 10.1126/science.1175834

Langdon, J. (1997). Umbrella hypotheses and parsimony in human evolution: a critique of the Aquatic Ape Hypothesis. Journal of Human Evolution, 33 (4), 479-494 DOI: 10.1006/jhev.1997.0146

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6 thoughts on “Pair Bonding & Ritual Marriage

  1. admin Post author

    Thanks! Chapais spins a fairly impressive argument and I have been thinking about it much lately, primarily from an ethnological perspective. I wonder whether pair bonding had similar (but lesser) effects on wolves? It could explain much about pack behavior.

  2. Renee

    Excellent article. The advent of agriculture would have been pivotal in the formation of pair bonding, instead of the other way around. The loose structure of the hunter gatherer tribes works well to ensure a (more or less) even sharing of meat in a time of abundance but agriculture requires a long engagement, so to speak, before the food is harvested. Planting pairs would be more successful than individual farmers and, in times of scarcity, would out-breed the more ‘traditional’ poly-amorous members of the tribe. Slowly natural selection would favor the pair bonded and their idea would become habit then tradition and, as such, be woven into religions the world over.
    As far as wolves go… yes, it seems that pair bonding has done the same thing for pack size, hierarchy though kin-bonds, and overall lower male-aggression. So what does that say about wolves’ herd culling strategies? Are they cultivating herds in a similar manner to the early cultivated grain of homo sapiens? Hidden in those similarities, between human and wolf, is another, more powerful cause, that resulted in pair bonding. But what is it?

  3. Cris Post author

    The idea is clever but faces this problem: all known hunter-gatherers engage in pair bonding. This surely means it has been around for a very long time, going back at least to the Upper Paleolithic 45,000 years ago. I don’t think agriculture did much to pair bonding other than to set the stage for property and unequal pair bonding. In other words, women in hunter-gatherer societies are much better off in general than their agricultural counterparts. Women are not chattel or subject to the “master” in hunter-gatherer societies.

  4. Renee

    Thank you for your quick response. I’m not trying to say that pair bonding did not exist… but that it wasn’t as ‘popular’ in pre-agrarian society as it is in post-agrarian society. Similarly, polygamy still exists… As recently as Columbus, some Native American tribes were engaging in multiple partner relationships. Often married men took additional wives in the case of death of a warrior and as long as the hunter was capable of killing enough game he was free to ‘marry’ as many women as he wanted. Also the African Maasai tribe, recently featured on BBC, engages in polygamy. It is true that these are only examples of polygyny. Nonetheless, evidence of pair-bonding as far back as the upper paleolithic does not negate the idea that agricultural society is more successful when the members are pair bonded and therefore, by extension, it can be deduced that agricultural societies favor pair bonding. I argue that these polygyny references in recent hunter gatherer tribal conditions reinforce the idea that agriculture may have had an impact on the marriage structure. Polygamy (of all types) decreases over time in direct proportion to the increase of agriculture. But you are completely right that women were not treated as property, in hunter gatherer society as frequently as women are in pair bond situations. It seems to be an unfortunate side effect of the house becoming the man’s domain and the increasing patriarchal organization of society. Ok I promise I’m finished arguing and I won’t refute further comments if you chose to write them! Thank you for your insightful posts. Keep up the good work!

  5. Cris Post author

    Many Native Americans were polygamous even post-Columbus; the Plains Tribes certainly were. There simply weren’t enough men to go around. Mortality rates from hunting and fighting were quite high.

    As for agricultural and post-Neolithic societies, I have no doubt that they encouraged or favored pair bonding (but then again, so do hunter-gatherers). Given that the Neolithic transition wrought fundamental change on all aspects of society, it would be odd if it didn’t also affect pair bonding and place greater emphasis on it, and subjecting it to rules or laws.

    A greater emphasis on pair bonding sure, but not a change in kind.

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