System Behavior & Dynamics

What Are System Dynamics?

Systems consist of objects and their interrelations. They are dynamic, respond to influences from outside and inside, and exhibit behavior whose causes cannot be reduced to single objects or connections. These complex emerging behaviors are called system dynamics.

Studying system dynamics allows insight into dealing with systems in the real world -- political, technological, biological, or otherwise. Because system dynamics of real-world systems cannot be predicted accurately, it is most useful to gain insight on an intuitive level: after a while, patterns will emerge naturally, and you will be able to detect opportunities and problems on a system level.

The System Behaviors Zoo

Below are common system behaviors you may encounter "in the wild." Detecting them helps you recognize patterns in complex systems.

Catastrophic Shift

It is easy to think of big systems as slow and lumbering beasts. Nothing could be further from the truth. Complex systems have the habit of, once triggered, changing very quickly indeed. Earth formation occurs in series of violent shocks (earthquakes, eruptions, hurricanes). Social systems produce riots and revolution. Economic systems produce sudden market crashes.

Behind these drastic changes is a tendency for every complex system to stabilize itself in an equilibrium (attractor state). When pressures reach a certain threshold, the system may suddenly switch to another attractor state without prior warning.

Rebound Effect

The rebound effect occurs when a change intended to improve the system triggers secondary side effects that counteract the intended change. In economics: an intervention to save costs by reducing prices is counteracted by increased consumption. The result is partly or completely offset by excess spending.

This system behavior is a primary culprit for the unfortunate reality that simply improving the efficiency of our existing systems step by step will not create significant reduction in resource use.

In 2000, a car with significant environmental benefits (~20%) saw a rebound effect: buyers who were already environmentally inclined felt less guilty driving it, drove more and faster, resulting in more impact than the efficiency improvements gained.

Exponential Effects

An exponential effect occurs when one parameter influences various other parameters, which multiply, causing the system to respond with exponential change. Biological organisms mostly grow exponentially before they plateau. Environmental impacts such as melting land ice have exponential effects on climate.

"The greatest shortcoming of the human race is our inability to understand the exponential function." -- Albert Allen Bartlett, Physicist

Law of Diminishing Marginal Returns

This general rule applies to all systems: for each single unit of production increased, the return is slightly less than the preceding one. Growing systems hit a ceiling of efficiency, after which it drops until the system collapses under its own overhead.

Archaeologist Joseph Tainter, in The Collapse of Complex Societies, makes a compelling case that all societal collapse is due to societies reaching and exceeding the top of this curve. Counteracting it requires reducing system complexity or achieving a resource efficiency jump on an exponential scale.

"Anyone who believes exponential growth can go on forever in a finite world is either a madman or an economist." -- Kenneth Boulding

80-20 Rule (Pareto Principle)

Roughly 80% of the effects of systems are caused by 20% of their causes. Named after Vilfredo Pareto, who discovered that 80% of Italian land was owned by 20% of the people. In complex projects, 80% of the time invested lies in 20% of the work (the tweaking stage).

Historical Momentum

Complex systems seem to have an ingrained collective memory. Even when all preconditions for change are met and public will is there, historic momentum can cause a system to change very slowly. To overcome it, search for positive exponential drivers to accelerate the transition, or provide a "transition boost" -- a short moment of excessive impulse.

Tragedy of the Commons

Named after Garrett Hardin's 1968 article: the depletion of a common resource shared by a group, even though each member knows the depletion works against their interests. This effect strengthens as systems grow in population and is a reason why some degree of centralized management is necessary in any system.

The Cobra Effect

British India tried to eliminate cobras by offering rewards for captured snakes. Locals started breeding cobras to collect rewards. When the program was cancelled, breeders released their snakes, increasing the population. The cobra effect occurs when an attempted solution makes the problem worse through unintended consequences.

Working with System Dynamics

Using SiD's network parameters, you can often find exponential patterns between individual parameters. Because complexity usually feeds into resilience in various ways, scaling a sustainable system often has significant impacts on its sustainability -- negative or positive.

Understanding these behaviors does not allow you to predict complex systems, but it does allow you to prepare for them, design for resilience, and find leverage points for change.