 The question of macro-scale social dynamics is of great interest to many. Questions of why the eastern islanders or Mayan civilization collapsed capture our imagination and challenge us to question whether there is some fundamental dynamic built into social systems through which we can interpret these events. We see clear, reoccurring patterns of instability that lead to financial crisis and the fall of brittle dictatorships. We also see social systems in places like Indonesia and Japan that have managed to develop over hundreds or even thousands of years in a sustainable fashion. And of course, this is not just an academic debate but a great relevance to our world as the 21st century context is challenging us to tackle this big idea of how to develop sustainable economies and societies. Complexity theory has a number of different models to help us in trying to formalize the dynamics of social systems and this area of research is called social dynamics. Social dynamics uses various mathematical and computational models but probably the most important and the one we'll be focusing on here is that of system dynamics. The systems dynamics modeling paradigm is used for analyzing complex systems in many different areas. It is part of systems theory and as such it takes a holistic perspective on a systems development over time trying to capture the basic causal interactions that drive its long term patterns of development. System dynamics is another non-linear modeling framework as it is very much focused on these feedback loops that we previously discussed. It is primarily concerned with how these feedback loops affect the systems development over time. If we remember there was just two types of feedback loops, positive and negative so we'll talk about how each of these affect the social systems development over time. As we've previously touched upon, negative feedback involves some balancing mechanism meaning what happens now will get balanced out by something that happens in the future. Thus there is some counterbalancing force that will hold the system within some limiting parameter values. For example if I take out a loan I will now have lots of money but this is being counterbalanced by what I'll have to pay back in the future. This counterbalancing creates a steady flow within the system. Whatever is being gained is being lost again at some future stage and thus we do not get a large accumulation within the system. Negative feedback is an inherent control mechanism. A system governed by this negative feedback can be said to be under control. We get positive feedback when the system starts to move in one direction without a counterbalancing force being exerted. Through this positive feedback we get non-linear exponential change and the system can now be said to be out of control. Non-linear change and non-equilibrium are a product of some broken negative feedback. This means that the system is not paying the full price for its operation. There is now some free source of energy being imported to the system and entropy is being exported to the system's environment. As an example we might think about the huge change within human society as we moved into the modern era. Human societies, demographics and economic output remained relatively stable for thousands of years due largely to the fact that it was fueled by manual labour that represents a negative feedback loop. In order to produce physical resources we had to do physical work thus taking from our stock of resources. In order to get more we had to give more thus balancing each other and maintaining some equilibrium. With the rise of modern technology and the use of petroleum we've broken this negative feedback loop. We now no longer have to do all this manual labour and this has led, among other factors, to exponential growth driven by this positive feedback loop. But of course as we know these fossil fuels and modern systems of technology are creating negative externalities. This positive feedback happens because of some externality. The cost is now being borne by someone or something else meaning that the counterbalancing force is being in some way externalised from the system. We could take the recent financial crisis due to subprime mortgages as an example of this. Within any financial security there is both a risk and a return. This creates the negative feedback loop. The more return you want the more risk you're going to have to take and this is a balancing mechanism. But with these toxic assets the risk was being externalised. Those who were making a return by supplying the assets were not bearing the true risk. The risk was being externalised to some third party and they were paying the cost for running the system by bearing that risk. This externality created a strong incentive for those supplying the assets to overproduce and this is the foundations of where we get the rapid growth from. As another example we might cite the Matthew effect that we previously discussed. Where the rich get richer there is clearly a positive feedback loop here. The more you have the more you'll get. The more popular a book, video or piece of music is the more people will want it. And experiments have shown that this is simply due to its popularity not because of any inherent quality to that item. There is of course a negative externality here. This excess attention that is given to those popular items is being taken from others. New books, videos or music will find it more difficult to gain traction. And thus the overall level of meritocracy in the system will be reduced and thus over time the overall quality will also be reduced. Another example would also be the phenomena of group think. The more people that believe in an idea or opinion the more of an attraction this places on others to also believe in it. Out of this we can get the Emperor's new clothes phenomena where people are simply believing in something because everyone else is also. Again this is a form of negative externality because no one is actually questioning the value of that thing this can distort any form of value system that correlates with the underlying context that is supporting it. And of course the classical example of this being bubbles within financial markets where people start to believe something has value just because it has value within the financial system irrespective of its value within the real economy and of course this is distorting the real economy which the whole system is ultimately dependent upon. This mechanism of positive feedback and negative externalities is a pervasive phenomena within socio-cultural systems. As an example within psychology we might think about the phenomena of confirmation bias which is the tendency to search for, interpret, favour and recall information in a way that confirms one's beliefs or hypotheses while giving disproportionately less consideration to alternative possibilities. This is a positive feedback loop as these hypotheses are self-fulfilling and there is a negative externality in that they are excluding other alternatives. In all of these examples this positive feedback dynamic coupled with negative externalities ultimately works to disintegrate the environment or context within which the system operates and thus reducing its sustainability. These positive feedback loops combined with negative externalities are key sources of path dependency. As positive feedback creates a strong attractor towards a certain behaviour while negative externalities work to degrade other possibilities and options. This creates a lock-in effect making it more and more difficult to choose some other path. Positive feedback makes it easier to do more of the same while negative externalities reduces the development of other options. What this means is inertia which is the resistance to change that we stay doing the same thing and become more incapable of doing other things. Think about learning a new language it is not so difficult for a child to learn a second language as they're growing up but the further you go down the path of speaking just one language the better you get at it and the more difficult it becomes to learn another. This is path dependency as the system develops more efficient at exploiting or processing a particular resource but also more dependent upon this single source creating a lock-in effect. So-called carbon lock-in is an example of this. Carbon lock-in refers to the self-perpetuating inertia created by large fossil fuel-based energy systems that inhibit public and private efforts to introduce alternative energy technologies. The source of carbon lock-in inertia arises from the co-evolution of large interdependent technological networks and the social institutions and cultural practices that support and benefit from the system's development. The growth of the system is fostered by increased returns to scale which is a positive feedback but this example will help to illustrate an important part of this dynamic surrounding complexity and interdependence. As the system stays developing down a particular trajectory this development means increased complexity more subsystems with greater interconnectivity and interdependence between them this complexity has to be maintained and it costs something to do that. The American anthropologist and historian Joseph Tainter has studied many forms of social collapse and he talks about this phenomena of increased complexity as such quote When I looked at what happened to ancient societies over long periods of time I realized the challenge they faced was the cost of their society becoming more and more complex as these societies face problems whether it was problems of external enemies or managing their own environment they would tend to develop more complex institutions very often this meant a larger military larger government or more control over their people and these societies tended to tax their citizens more heavily to pay for their complex problem solving the difficulty with complexity is that it always costs something in ancient societies that I've studied for example the Roman Empire a great problem that they faced was when they would have to incur very high costs just to maintain the status quo invest very high amounts that don't yield a net positive return but instead simply allow them to maintain what they've already got in all of these previous examples the positive feedback loop is insulating and protecting the system from disturbances from its environment group think reduces the social systems exposure to external ideas that might disturb the consensus confirmation bias reduces the exposure of our hypotheses to disturbance our store of petroleum enables us to create artificial environments independent from the natural environment when we reduce the disturbance during the system's development we increase the tightening of the coupling within the system the connections become stronger and as it develops they become more dense a system that is moving towards a critical point has a high degree of connectivity and interdependence between its subunits this is called high percolation where we can think of percolation as simply the density of the connections within the system a good example of this comes from research done on forest fires in California which has shown that if the forest receives less disturbances that is to say if we reduce the number of small frequent fires then the density of trees within the ecosystem builds up it becomes more tightly coupled as the percolation increases this creates more pathways for the fire to spread from tree to tree as this percolation becomes more dense the system reaches a point from where any small fire can now spread through the whole forest creating a large systemic effect and this is what we call criticality the system has reached a critical point when we have all of these factors positive feedback driving the system down a particular trajectory negative externalities which are degrading alternative options the growing cost of maintaining the system's complexity tight coupling interdependencies and high percolation then the system is moving into a critical regime the term critical in mathematics and physics relates to or denotes a point of transition from one state to another these critical points before a transition are studied within the domain of nonlinear dynamics called catastrophe theory catastrophe theory studies dramatic changes within the system's topology the most famous of which being what is called the cusp curve where the topology dramatically folds back in itself creating a cliff-like structure a system is then said to be critical if its state changes dramatically given some small change in an input value to a control parameter once the system has reached its critical point even the smallest perturbation can have major consequences and this is uncontrollable as the system becomes more critical its eventual collapse becomes greater and its eventual transformation becomes more inevitable but less predictable we know it's going to happen because any small event can trigger it at this stage but because it is in this critical state and so many different small events can trigger this transformation we don't know exactly which one will or when it will beyond the critical point we get some runaway effect a tipping point has been passed and the system moves into a phase transition as it is now irreversibly moving into a new regime at this stage the system becomes extremely nonlinear it breaks down almost completely massive direct interventions within the system can have a very negligible effect you as a government can put billions into the market buying up toxic assets with this having only a negligible effect on the price because the failure is distributed out any small event can trigger a large systemic effect in this situation there is no real possibility for control previously unknown interconnections and interdependencies become revealed and random events can determine significant outcomes within a social system this is what is called societal collapse the system is moving to a lower state of functionality as the social structure breaks down this process of non-equilibrium social dynamics is equally applicable to social systems on the micro-macro level from a financial trader going boom and bust through the positive feedback loop of irrational exuberance to small extremist groups formed out of the positive feedback and negative externalities of some ideology built on out-group derogation and of course it is applicable to whole societies as described by conflict theory where the positive feedback of the rich-get-richer effect leads to increased inequality which if left uncounterbalanced will move the social system towards extreme polarization at some point the oppressed simply can't bear the oppression anymore and we get ensuing riots and revolution and of course we also see this pattern of societal collapse on the macro level of whole civilizations such as with the Roman Empire this whole dynamic of positive feedback driving exponential growth and decay is a form of what is called self-organized criticality which is a property of a nonlinear dynamical system that has a critical point as an attractor a good example of this would be the tragedy of the commons where each individual is driven through a positive feedback loop to overuse the commons with the negative externalities from this destroying the whole resource and leading us to collapse this is self-organized criticality because it is the way that the dynamic is set up that attracts the agents towards pursuing agendas that lead to a macro level critical outcome in this video we've been looking at social systems dynamics we talked about how positive and negative feedback loops can give us a model for interpreting these dynamics we briefly discussed how negative feedback can give us a relatively stable process of development involving counterbalancing forces that maintain the system within some equilibrium we then went on to talk about a non-equilibrium process of change where this negative feedback gets broken and positive feedback coupled with negative externalities leads to rapid unsustainable development within this dynamic path dependence, lock-in and heightened percolation all lead to eventual criticality and a phase transition in this module we've been using these very simple tools of positive feedback loops to describe what are in reality very complex social processes of change feedback loops do offer us some deep insight into these dynamics but if we want to get a more sophisticated and complete representation we would need to add a few more tools to our toolbox including the ideas of adaptation, diversity and the process of evolution all of which would help us to understand better how social systems managed to develop in a more sustainable fashion we'll be covering evolution and adaptation in a later section to the course so we'll move on for the moment