The Evolution of Hierarchy

By Peter Turchin December 20, 2014 17 Comments

Two weeks ago I went to a studio in Amherst, MA, to participate in a BBC Forum on Hierarchy. It was broadcasted last week, and you can listen to it here.

I arrived at the studio in plenty of time, but there were inevitable SNAFUs. First, I couldn’t get into the building (not sure why they lock it during the business hours), and for a while nobody was responding to my frantic hammering at the door. Then, I had to drive to a distant parking lot (they did not have a parking space for me near the building) and run back, so I started the program out of breath.

Still, I thought the program went quite well. The format of the show doesn’t force you into reducing the complexity of your ideas to sound bites; instead giving you time to develop your argument in a logical way. The other two panelists were really interesting and articulate people (read about them on the BBC site). It was a pleasure to listen to their perspectives.

Sign up for our newsletters

I wish to receive updates from:

In today’s blog I’d like to revisit the main idea I was trying to get across. Nothing can substitute the written word for clarity and conciseness.

For over 90 percent of our evolutionary history humans lived in small-scale groups. Agreeing on a common course of action to achieve collective goals was relatively easy. It is quite possible to come to a consensus in a small group of ten or fewer people simply by having a common discussion, listening to everybody’s concerns, and not allowing anybody to dominate the decision-making process. If such a group finds it impossible to achieve a consensus, it disbands and reforms in a different configuration, or sheds uncooperative individuals.


It is much harder, but still possible to concert a common policy in groups consisting of many tens of individuals; very difficult in groups of hundreds; and simply impossible once you get into thousands. That’s probably one of the fundamental principles of social dynamics (which the Occupiers did not seem to understand).


The only way that large human groups can arrive at a common course of action is by structuring interpersonal connections. Imagine a large human group as a network in which any particular node (a person) has a thick connection to just a few other people, between 4 and 10 of such connections. This is a small enough number so that each person in a pair can know the other quite well, and they can rapidly coordinate their objectives and actions.

So the coordinator at the center of the network speaks to and gets feedback from ten other people. Those ten speak to ten more people each, and so on. It is possible to connect a group of any size using this scheme, by adding extra levels of communication and decision making. For example, a society with one million members would need six levels. We need only 10 levels to connect everybody on Earth!


This is a hierarchical organization in its neutral, informational (or, as my father would say, cybernetic) sense, which should not be confused with ‘hierarchy’ in its negative sense, that is, unequal distribution of power. Biologists are quite used to speaking of hierarchies in the neutral sense (for example, we speak of life being organized in a hierarchical way, from molecules to organelles, to cells, to tissues and organs, to individuals, and to populations or societies).

The problem, of course, is that as soon as you put someone in a central position of a decision-making network, you give them a lot of structural power, and they can, and often will, attempt to convert it into more malignant forms of power: ability to order others around, and acquisition of a disproportionate amount of resources. If there are no effective checks on leaders, then hierarchy breeds inequality. Sociologists even have a name for this, the Iron Law of Oligarchy.

So what happened to humans during the Holocene (which started roughly 12,000 years ago with the end of the Ice Age) is that they spread all over the Earth, and their numbers increased to the point where human societies came into frequent contact and conflict with each other. Warfare became more intense and exerted a very powerful selection on human societies. Societies that were larger and better organized outcompeted smaller and more shambolic ones. Hierarchical organization was one of the cultural traits that was heavily favored by the new selection regime in the Holocene.

Politically centralized societies (chiefdoms) appeared and spread, and then evolved into larger scale societies, complex chiefdoms and archaic states. These societies were extremely unequal. Large segments of populations were enslaved, or became the fodder for bloody rituals, in which multitudes were sacrificed on tops of pyramids. The rulers set themselves up as gods on Earth.


Such extreme forms of inequality alienated the 99 percent of the population, and corroded society-wide cooperation. Ironically, inequality reduced the ability of the despotic archaic states to compete with other societies (which is why they were extremely fragile, and often did not survive their founders). Now cultural evolution began working ceaselessly to make societies less despotic and less unequal. Not because evolution cares about our wishes (and, particularly, that the majority of the population prefers more equitable outcomes), but because more equal, just social arrangements win in competition with the grossly unequal, tyrannical ones.

We’ve come a long way since the days of the early despotisms, but we have an equally long way to go to construct truly just societies. What lessons do Sociology and Cultural Evolution have for us?

First, it’s a pipe dream to imagine that a large-scale society (e.g., a million people or more – a small nation by today’s standards!) can be organized in a non-hierarchical, horizontal way. Hierarchy (in its neutral sense) is the only way to organize large-scale societies. In itself, it’s not a bad thing.

Abuse of power and gross inequality are unquestionably a bad thing. Evolution has been working to eliminate the worst excesses, but we need to help it along. ‘Evolution’ sounds like such a faceless, impersonal force. But it actually is a result of a multitude of actions of real people, from common folks to rulers. Our societies today are much less despotic than the early ones, thanks to such people as the Israelite prophet Amos, who denounced powers that be, and the Chinese sage Confucius, who championed justice, sincerity, and morality.

So what we need is not less hierarchy, but more control over our leaders to ensure that they govern for the collective good, rather than for selfish needs of themselves and their cronies. How we achieve this end is a big question, to which I don’t have a ready answer – and certainly not something that I’d want to deal in this post.

Published On: December 20, 2014

Peter Turchin

Peter Turchin

Curriculum Vitae

Peter Turchin is an evolutionary anthropologist at the University of Connecticut who works in the field of historical social science that he and his colleagues call Cliodynamics. His research interests lie at the intersection of social and cultural evolution, historical macrosociology, economic history and cliometrics, mathematical modeling of long-term social processes, and the construction and analysis of historical databases. Currently he investigates a set of broad and interrelated questions. How do human societies evolve? In particular, what processes explain the evolution of ultrasociality—our capacity to cooperate in huge anonymous societies of millions? Why do we see such a staggering degree of inequality in economic performance and effectiveness of governance among nations? Turchin uses the theoretical framework of cultural multilevel selection to address these questions. Currently his main research effort is directed at coordinating the Seshat Databank project, which builds a massive historical database of cultural evolution that will enable us to empirically test theoretical predictions coming from various social evolution theories.

Turchin has published 200 articles in peer-reviewed journals, including a dozen in Nature, Science, and PNAS. His publications are frequently cited and in 2004 he was designated as “Highly cited researcher” by Turchin has authored seven books. His most recent book is Ultrasociety: How 10,000 Years of War Made Humans the Greatest Cooperators on Earth (Beresta Books, 2016).

Sign up for our newsletters

I wish to receive updates from:


  • SirNemesis says:

    Anyone who has done any significant editing on Wikipedia can readily understand just how difficult it is for large groups to function without a hierarchy.

    • Peter Turchin says:

      Any large group cannot function without hierarchy. They either acquire it and become successful, or sit around debating endlessly, or fall apart.

  • Antonio says: I read to Victor M. Yakovenko for mathematical models of inequality. I think that It’s very interesting. What do you think about this?

  • Lee Doran says:

    This is an excellent post Peter and a good basis for further thought and discussion. I have one initial thought and that is we are bedevilled not only by the requirements for hierarchy in a structural sense in order to make it work, but we are also challenged by the values in whose ‘favour’ any given hierarchy is working.

    It seems to me that, most basically and generally, specific hierarchies ‘work’ in support of their given (and usually quite well-defined ‘in-group’) — and they often do it (or did traditionally) by demonizing and de-humanizing their out-group(s).

    An associated and critical issue, in my view, is the values that drive their specific group. If they are group-specific and local and relatively immediate (food, or shelter or women or beads or…) that’s one thing… if they are larger and more inclusive (the nation, the continent … dare we think: the globe!?) then we are getting close to our ‘modern’ dilemmas… of globalization socially and climate physically…

    As more and more people attend to the more universal issues and their enabling values, the closer we get to something like openness and access that of necessity seems to bring equity with it… or so I would hope!

    Thanks again!

    Best to all,


  • a missing foundation for the Jeffersonian “checks & balances” model: “the hundreds”

  • Ross David H says:

    I found fairly convincing Mancur Olson’s analysis was on to something. To summarize, he thought that it took time for small groups to acquire the ability to manipulate the government to their interests. The longer it had been since a society had been disrupted by a defeat in a major war (or other equally-sized shock), the smaller the groups that were in control of the government.

    He wrote this before the Wall fell, but I think that Germany’s unification served as a benevolent shock of this sort, and explains a lot of why Germany has done better since 1989 than Japan; the latter has had longer (since WWII) to acquire entrenched, smaller interest groups in control of things, whereas in Germany the barnacles were shaken loose in 1989 (for example the current Chancellor wasn’t even a West German citizen).

    What is somewhat lacking though, as far as I know, is a good, objective metric for how far this process has gone in a given society. I know you have been working on this kind of thing, Dr. Turchin, but I’m curious if there’s a single metric (presumably a weighted composite of several others) that you think can be used to test an hypothesis of this sort. Have you looked at James K. Galbraith’s inequality database, for example? It only includes industrial economies but it might work for more recent societies.

    • Peter Turchin says:

      I am familiar with this argument of Olson. Looks plausible. However, as far as I know it was never tested empirically.

  • Doug Jones says:

    String quartets don’t need conductors; symphony orchestras (past a certain size) generally do. In the heady early days of the Soviet Union, the effort was made to do without conductors for symphony orchestras. The main one lasted for ten years before being disbanded. Check out “Conductorless orchestra” and “Persimfans” (=First Conductorless Symphony Ensemble) on Wikipedia.

    Doug Jones

  • Yoram Gat says:

    > The problem, of course, is that as soon as you put someone in a central position of a decision-making network, you give them a lot of structural power, and they can, and often will, attempt to convert it into more malignant forms of power: ability to order others around

    What is the difference between being “in a central position of a decision-making network” and having the “ability to order others around”? How can the former be legitimate while the other malignant?

    > more control over our leaders to ensure that they govern for the collective good

    This is the usual failed recipe of “checks and balances” or “accountability”. Supposedly we first give “leaders” power to abuse and then somehow make sure they don’t.

    A more promising (and historically validated) approach is setting things up so that decision makers are not pre-disposed to abuse their power to begin with. This can done by having the interests of the decision makers aligned with those of the population. This in turn is done by using sortition to select decision-makers (rather than elections or any other competitive mechanism).

    Instead of having rule by an elite, with its own distinct characteristics and interests, sortition-based selection relies on the law of large numbers to guarantee that the decision-makers, who are a statistical sample of the population, are truly representative of the population – their material interests, their ideology, and any other characteristic – are the same as those of the population. The decision-makers can then be expected to promote the interests of the entire population by promoting their own.

  • lpetrich says:

    On the subject of inequality, one has to be careful that some proposed solution does not produce Yet Another Arrogant Ruling Class. I like George Orwell’s Animal Farm, an animal allegory about Soviet Communism and how it produced a new ruling class.

    I’ve found some interesting research that shows how economic and social inequality can emerge without the winners being especially skilled or diligent or crooked, although such attributes certainly help. PLOS ONE: Entrepreneurs, Chance, and the Deterministic Concentration of Wealth It describes simulations of populations of simulated entrepreneurs. Each one invests their wealth in various businesses and the like, though the simulations only include the return rates, which are positive with some scatter. It’s the scatter which makes some of the entrepreneurs come out ahead, because some are luckier than others. The average return being positive then makes a small fraction of the entrepreneurs much more wealthy than the others, to the point that nearly all the wealth becomes owned by only a few of them.

    It would be interesting to do this sort of simulation with finite resources, like land, or finite markets, like customers for various goods and services. One may also include bankruptcy for entrepreneurs whose wealth becomes too small, so they drop out of the simulation. It would be interesting to see if one gets integrative-disintegrative cycles out of such simulations.

  • Helga Vieirch says:

    This is a quibble. I don’t think you have quite managed to distinguish here between the role of ranks and the role of hierarchies. Leadership roles can emerge out of very informal ranking systems, but hierarchies tend to create more long-lasting leadership which slips into systems of top-=down authority fairly quickly without checks and balances, as many have recognized.

    You have presented a model of how decisions about joint activity are taken within small groups, as are typical of the smallest organizational segments of any society, not just hunter-gatherer camps, but you fail to mention that among foragers too, there are vast networks of interconnect and that seasonal aggregation into larger groups is a pattern found to be almost universal. At such times, high rank among people translates into greater responsibility for keeping food distribution fair, and for resolving conflicts.

    I had a shudder when I read the following statement:

    “So what happened to humans during the Holocene (which started roughly 12,000 years ago with the end of the Ice Age) is that they spread all over the Earth…”
    Human spread all over the planet LONG BEFORE THE HOLOCENE. It was the hunting and gathering economy and associated social systems that accomplished this.

    Next you say “ Hierarchical organization was one of the cultural traits that was heavily favored by the new selection regime in the Holocene.”

    I wonder how many of your readers might mistake this “new selection regime” for an evolutionary one – altering the KIND of biological human that was favoured by higher frequencies of hierarchical structures in group decision making and leadership? I hope most would not jump to this kind of inference.

    I think it important to make it quite clear that human beings did not then, or since, need to have different kinds of cognitive or behavioural biology to adjust to the economic diversification of the Holocene. If that were so, a person from a formerly egalitarian culture could not cope with living in modern industrial state.

  • Less Entropy says:

    Cross reference the recent discovery by Noonan et al in Oxford of the hierarchy centre in the limbic system. Then buy a tank and some fish and watch them slog it out for dominance. Hierarchy isn’t a cultural invention – it is hard-wired and ancient. Incidentally, you may have heard Professor Steve Jones say (BBC radio) that EP has made no testable predictions. The existence of the brain centre for hierarchy was predicted from EP (okay, by myself).

  • John Strate says:

    The argument is sound and is supported by empirical evidence. Simpler political communities do less (have fewer functions) than more centralized ones. At a minimum, political communities engage in external defense or protection. Offensive warfare follows. Larger and more populous political communities add functions as opportunities for the provision of new public goods appear. I’d add that more centralized political communities typically include territorial subdivisions that are organized in a hierarchy. How to prevent abuses of power is an old question. Warfare does eliminate political communities with more autocratic and abusive rulers. It happens internally too. The greater the perquisites of political power, the more likely that other elites will be tempted to usurp that power. New rulers may be less abusive than those they replace.

  • leigh says:

    nice. This is what makes “free “market economics an illusion..

  • David Draguta says:

    What if we have local direct democracies with common ownership of the means of production put together through voluntary association into a global federation? No one social cell has to ever become so big as to necessitate hierarchy.

Leave a Reply

<textarea name="ak_hp_textarea" cols="45" rows="8" maxlength="100" style="display: none !important;">

This site uses Akismet to reduce spam. Learn how your comment data is processed.