No, That’s Not How Anthropologists Think Of Human Social Organization

There is recent a video posted on Slate that summarizes a recent study claiming to give support to the anthropological position that “hierarchical organization of human society is deeply nested in human psychology.” As I sat and watched the video, I thought surely this is a problem of science reporting and the research does not make such claims. Alas, the video is quite accurate in describing the research.

That research, by Benedikt Fuchs, Didier Sornette, and Stefan Thurner (none of whom are anthropologists as far as I can tell) and published in Physics and Society (definitely not an anthropology journal), claims that its conclusions support “the anthropological literature”; yet, there is hardly any anthropological literature cited in the study. In fact, judging by the bibliography, it seems entirely based on the work of only a couple of anthropologists.

The main piece of evidence the research uses is this thing called Dunbar’s number, which is an idea proposed back in the 1990s by anthropologist Robin Dunbar that individual human beings cannot comfortably maintain more than 150 stable relationships. Dunbar arrived at this number not by examining how humans actually interact, nor by averaging numbers found in the anthropological literature, but by looking at data on how various social non-human primates interact. He arrived at that number by taking the ratio of non-human primate social group size to their neocortex volume and then extrapolating the value to an average human neocortex volume. This number led to the development of “the social brain hypothesis,” which says that there is an upper cognitive limit on the number of personal relationships an individual can reliably maintain. Dunbar then searched the ethnographic and historical literature for this number and, lo’ and behold, he found it everywhere, from anthropological reconstructions of Pleistocene groups to ancient Rome. It is important to note that other anthropologists have come up with different numbers, though this concept is not highly utilized in anthropological studies of human social organization.

Frankly, from my perspective, this is not even a particularly interesting way of thinking about human social organization and interaction in anthropology. And needless to say that’s a highly problematic way of drawing conclusions about human social interactions.

Another premise of the study is the application of the Horton-Strahler number to human social organization. The Strahler number originated in studies of hydrological systems and has been used in the analysis of other hierarchical systems, including biological systems. And this is where I find it troublesome to apply it to human social organization. From the video:

It’s used in mathematics as a way to measure the hierarchies of biological structures, like people and the way they interact in groups, and social structures.

But the way people interact in groups is not a biological structure, it’s a sociocultural structure. Society is not an organism; that idea fell out of use in anthropology many decades ago, and it’s annoying to find it still being espoused in public arenas. Later in the video, the narrator makes this claim:

When the researchers applied the Horton-Strahler stream [to the groups in the video game world], they found a branching hierarchy with the same scaling ratio that anthropologists have documented in society as a whole.

The problem here is that anthropologists have not documented this scaling ratio; one particular anthropologist (Dunbar) and some other researchers (based on Dunbar’s work) came up with the ratio and combed the ethnographic and historical record looking for the ratio. But that’s not even the most egregious problem with the above statement. Anthropologists have not documented anything about “society as a whole.” There is not one “society as a whole”; in fact, there are many societies. No anthropologist would ever describe human social organization as being one whole society.

Anyway, the video summarizes the research this way:

Anthropologists track the way humans interact and the hierarchies they create. And what they found are patterns consistent throughout history all the way back to hunter-gatherer groups. Even at the onset of civilization, human groupings have always been highly structured.

This is simply not true. The research the video is describing relies on the work of Dunbar rather than a robust review of the literature. When we look at what anthropologists actually say about foragers (hunter-gatherers), it becomes clear that it’s more complicated and complex.

What we think we know of the social structure of Pleinstocene foraging groups is often based on the highly problematic practice of using contemporary foragers as analogs for the past. But they are not primitive versions of us. They are living peoples with particular cultural histories that are deeply entangled with processes of globalization. They are not living artifacts of a bygone Stone Age frozen in time for us to use to make sense of our own particular histories or support our mythologized narratives of human nature. And even if that was an acceptable way of interpreting the past, there are only a few dozen true (nomadic) foraging groups left in the world today (many contemporary foraging groups also rely on animal herding and/or horticulture), so it is hard to imagine how it could be okay to make claims about 99% of human existence with such a small sample.

Further, I think it’s important to ask what “highly structured” is supposed to mean here. We know that many forager groups are egalitarian in their structure (there are, of course, exceptions). And while they do make distinctions in social organization, most often around age and gender, they do not necessarily place these distinctions into a hierarchy. Is a group that organizes itself only around age and gender without any strict hierarchy a “highly structured” group? I’d say no, but it depends on what “highly structured” is supposed to mean.

I do think it is interesting to look at human social organization and be able to utilize various mathematical formulas to highlight interesting patterns that emerge. But I do not think it is wise to use such formulas and the research of a couple of anthropologists to make universal claims about human nature. The claims in this research, while cool to think about, should be taken with a large grain of salt. Particularly when videos like the one on Slate frame this as an anthropological study. It’s not—it’s a mathematical study published in a physics journal.

In spite of what this video says, anthropologists today generally do not look at societies in the way outlined in this research, using mathematical modeling to make sweeping claims about the entire history of Homo sapiens sapiens. We are much less interested in making (and are, in fact, quite skeptical of) universal claims about human nature than we are about looking at how particular cultural histories create diverse human societies.


Will is the admin of Queereka, part of the Skepchick network. They are a cultural/medical anthropologist who works at the intersections of sex/gender, sexuality, health, and education. Their other interests include politics, science studies, popular culture, and public perceptions and understandings of anthropology. Follow them on Twitter at @anthrowill and Facebook at

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  1. Hmm. Personally, I wish this was studied more, because I can’t help but think Dunbar might have the number not quite right, but he never the less got things accurate. We see a lot of “lumping” going on with humans. This is something that other primates lack the capacity to do, but it is both potentially detrimental, in some cases, and beneficial in others. In essence, we can “lump” much larger groups of people into categories like, “Those dang enemy Muslims.”, or, “People just like me, who are basically good.” Been reading Penn Jillette’s first book and wanted, in more than a few cases, to slap the libertard and yell, “No, people are not basically all good, they are just basically all people, and that is why your nonsense idea that they would all, without social systems, help each other up out of the mud, instead of just walking past in apathy, is, to use the name of your old show Bullshit!” We lump. If we lump them in to a group as, “Like us, and deserving of help.”, we might still, never the less, lump them in as, “But less important than the people I know personally, so I won’t help them anyway.” Or, we can do the opposite, and lump them in with, “Lazy, socialist, liars, who just want stuff for free.”, like some other people do. But, one thing we don’t do, at all, well, is deal with each and every one of them on a case by case basis. We take short cuts.

    Our short cuts are a vast improvement over what any less cognitively creative species can manage, but… its also vastly worse, since they don’t arbitrarily decide that every monkey on the other side of the hill needs to die, purely because they are there either. But, again, I don’t doubt, at all, that we have limits on the number of people we can deal with as individuals. I do know, however, that, for good or ill, we can cram a whole hell of a lot more people into a category, and apply to them all a set of presumed attributes, as a short cut for not being able to know them well enough to do otherwise.

    Otherwise, yeah, two anthropologists… are hardly sufficient to specify what/where those limits really are, and I get the impression that they ignored the categorization ability, which allows for a much more dynamic, and less hierarchical result (at least outside of authoritative world views, like.. say, the right wingers, who think everything is a bloody hierarchy, including probably whether or not their socks are higher in the food chain than their underwear, or something).

    1. Yeah, I definitely don’t have an issue with the idea that there may be some cognitive upper limit as to how many relationships an individual could have, and I agree with you that they could have explored categorization in a more robust way. But that’s not really what most anthropologists are interested in. We are more interested in qualitative questions, like what those relationships mean to people, how and why they go about forming them, how and why they maintain or cut off relationships, and so on. This seems more a question of psychology than anthropology to me (maybe psychological anthropology or social psychology even), but again we know how problematic conclusions drawn from psychological research can be!

      1. I wouldn’t say that anthropologists are not similarly prone to reaching bad conclusions. A lot of *all* fields is a tendency to only think “inside the box”, when it comes to prevailing theory, and to miss one’s out possible confabulation of the result (this is almost inevitable when dealing with something that thinks). A lot of older research is steeped in the “assumptions” about what they should be seeing. The two also overlap a lot. Like.. was the sex studies by Masters and Johnson “Psychology” or “Anthropology”? Would it have been one, but not the other, if it had been one some tribe some place, not people in their own country? How many things did they come real close to confirming to be true, which where not, until they had the guts to say, “The data just doesn’t say that, so something else must be going on.”? How many others have written “standing” texts, which are considered the “defacto” sources for certain subject, who completely failed at this, especially from the 30s->60s?, when even bloody archeology had its head up its collective butt in some ways (like burning mummies, instead of studying them, for a good segment of time)?

        The point being that, to me, the question, “What does someone’s relationship, and how does it effect other relationships, to a ‘category’ of people?”, ***is*** a perfectly reasonable question to ask, in either field. ;)

  2. Very interesting. As someone who likes applications of math to describing the behavior of humans and other animals, I think your second-to-final paragraph is really apt, and something people like me should be well-advised to heed.

    I would like to defend the social brain hypothesis a little, though. To be clear, “Dunbar’s number” is not really the central claim of the social brain hypothesis, it’s more of a corrolary. And I completely agree that the argument in favor of such a number being rooted in cognitive complexity is much weaker (e.g., it’s hard to disentangle whether a limit on social group size is due to too much cognitive complexity, or the investment of time and other resources needed to maintain each relationship — in non-human primates it may be the former, but in humans I suspect it’s the latter). The main claim of the social brain hypothesis is that among primates, the most important evolutionary pressure driving changes in the neocortex, and the prefrontal cortex in particular, is the computational demands of complex social interactions. Dunbar’s original formulation used neocortical volume as a proxy for its complexity and computational power, and species-typical social group size as a proxy for social complexity. As proxy measurements, these are both really crude, and can be criticized on a number of grounds, but at the end of the day there’s actually a pretty clear relationship between the two among non-human primates. (There’s also some recent work suggesting that this relationship holds ontogentically as well as phylogenetically, which is pretty interesting.) But I do think that the extent to which we should interpret this fact to be important in understanding human behavior is open to debate.

    I’m afraid I didn’t have time to watch Timothy Ingold’s talk that you linked to. (I’m supposed to be writing my dissertation right now…) But based on the abstract, I think his criticisms of the social brain hypothesis are mis-aimed. He says, “In this lecture I show that the hypothesis is misconceived in three respects. First, it rests on a false opposition between social and ecological relations.” This is definitely not true. I don’t know if this is based on something Dunbar wrote, but if Dunbar ever said that, he’s wrong too. It is possible (and in certain cases necessary) for some neural systems to play a role in helping an animal navigate both social and ecological relations. There are, for example, similarities in the kinds of computations that need to be performed during foraging and during certain types of social exploration, and some systems in the brain could be (and in my opinion probably are) important for solving both problems. In this case, all that is necessary for the social brain hypothesis to apply is that the sophistication of such neural systems among primates is more than adequate to the task of foraging, but under strong selection when the demands of the social environment increase. There is research by Dunbar and others suggesting that this is the case. No “opposition between social and ecological relations” is necessary.

    I wrote responses to his other two points, but upon reading it, I realized I was probably becoming overly tedious even by my standards (okay, even more overly tedious), particularly since this wasn’t really the main point of your post. I couldn’t let this statement stand, though: “I argue, to the contrary, that the brain is not an organ but an entanglement of neural tissue…” I’m afraid this strikes me as nonsense. It’s like saying, “You are not a human but a bag of salt water with a little protein and lipids.” Arguing that the brain is not an organ is a display of either profound ignorance or unproductive contrarianism.

    But back to the main point about the use of the Horton-Strahler number, and regarding what’s meant by “highly structured” in this case, I think that’s an important question. Will, you noted that many forager groups have highly egalitarian societies, as opposed to hierarchical societies. I’m not really certain, but based on what I understand about the kind of analysis being used to produce the Horton-Strahler number, I’m not sure that’s the notion of “hiearchy” that’s meant here. I think the “hierarchy” in question is more in the social network organization of, e.g., individuals belonging to family groups belonging to “clans” belonging to “tribes”. (Please forgive me if I’ve used those terms incorrectly, but I hope you understand my meaning.) As I understand it, the presence or absence of a “dominance hierarchy” should be unrelated to the kind of thing that the Horton-Strahler number measures. So I’m guessing that what they mean by “highly structured” is that the social network of who has a relationship with whom (without considering the nature of that relationship) exhibits that kind of tiered clustering.

    Anyway, even if we take the result of the study at face value and believe that a wide array of human societies, including online “societies”, exhibit a similar mathematical property in their social networks, I definitely agree that it is a huge leap to say that this provides evidence for the idea that the “hierarchical organization of human society is deeply nested in human psychology.” I can think of all kinds of alternative explanations for the result.

    1. Good lord what a wall of text. This is at least the second time I’ve done this on Skepchick, sorry.

    2. Thanks for the comment, biogeo. No need to be sorry, you bring up great points.

      I think what Tim Ingold is trying to get at is that there is a false separation in the social brain hypothesis between what is “social” and what is “ecological”–they are both always already entangled in his view. That’s certainly open to debate, but I think it’s an important point to remember when thinking about social organization. For his point about the brain not being an organ but an entanglement of neural tissue, I agree with you that that is a weird thing to say. He’s probably trying to get at extending the idea of the eco-social relationship to the brain–it is also a “social” (i.e., neural) network of sorts. Ingold is definitely one of the more…poetic? thinkers in anthropology.

      Re: Horton-Strahler number, that’s exactly what I was curious about. The word “hierarchy,” when used in anthropology, does not have the meaning you’ve elucidated here as how it’s meant in mathematics. And, more importantly, the general public (to which this video was aimed) thinks about “hierarchy” as a ranking rather than a particular kind of mathematical structure. This seems to be a classic case of common words with technical meanings that lead to misunderstandings (e.g., “theory”).

      I wonder what a not-highly structured set of social relationships would look like. I ask because, if all social relationships in all social animals make these kinds of patterns, I am unsure what the purpose of making the “highly” qualifier is. I haven’t read up on that, though, so I’m not sure what the state of that research is.

      Good to hear from you and I hope your dissertation is coming along well!! =)

      1. “I think what Tim Ingold is trying to get at is that there is a false separation in the social brain hypothesis between what is ‘social’ and what is ‘ecological’–they are both always already entangled in his view.” Well, I definitely think that’s a fair point, and in fact my tendency (being a biologist) is to view the social as one important part of the ecological, rather than wholly distinct.

        On your point about the word “hierarchy,” I totally agree. I encounter these kinds of jargon problems all the time in my work. In this case, maybe they would have been better off talking about “nested group membership” or something.

        That’s a really good question about “not-highly structured” social relationships. I think there are probably just a few basic patterns here: totally unconnected “networks”, for completely non-social animals (to the extent that such a thing even exists); very “flat” networks where every animal has about the same number of relationships, representing, for example, highly territorial animals who have relationships only with their neighbors (e.g., the eastern fence lizard); networks consisting of tightly connected clusters which are largely unconnected from each other, representing species that form stable family units (e.g., scrub jays, beavers); and “highly structured” networks of the sort described here (e.g., macaque monkeys, American crows, orcas, and of course humans). There might be a few other types of patterns I haven’t considered. I’m not really sure to what extent the social networks of humans, as assessed by techniques like the one in this study, can be quantitatively or qualitatively distinguished from those of other “highly structured” animal societies. My guess is that if you ran the same analysis on rhesus macaques or gelada baboons you’d find something roughly similar.

        Actually, if you’re interested, a friend and colleague of mine is a primatologist who’s a leading expert on applying social network analysis to non-human primates. This is an academic review she wrote on the topic: (If she says anything in there that contradicts what I just said, she’s definitely right.)

        Thanks for the well-wishes! To be honest, I’m slightly panicked at how much work I have left before it’s due. Apparently one of my solutions to this panic is to check Skepchick compulsively, which may not be the most adaptive strategy…

        1. I think you’re getting at what Ingold is critiquing about the social brain hypothesis, which is that the ecological (the study of the interactions among organisms/environment) is always already social in the sense that organisms always interact with other organisms (even “non-social” organisms) as part of their environment.

          Those are interesting breakdowns of the degrees of complexity in social structures. I can see how, from a biological (the discipline) perspective, that makes sense. From an anthropological perspective, I guess we are a bit anthrocentric and I think of varying degrees of complexity in human social structures.

          Ah, interdisciplinarity! ;)

          Thanks for the suggestion on the paper. I will definitely give it a read.

          I hope you will drop a note when you’re done with your dissertation! I’d love to see what you’re work is about. You can always get in touch through the contact form. ;)

  3. I heard ‘computer simulation’ and from that point on, my brain just started playing the Mario World 1-1 theme.

    I’ve seen computer simulations that started with the presumption that acupuncture cured about 60% of patients with an affliction, tested them on, say, 1000 simulated patients, and, what do you know? 60% of the patients on acupuncture were cured!

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