Let's face it, the universe is messy. It is nonlinear, turbulent, and chaotic. It is dynamic. It spends its time in transient behavior on its way to somewhere else, not in mathematically neat equilibria. It self-organizes and evolves. It creates diversity, not uniformity. That's what makes the world interesting, that's what makes it beautiful, and that's what makes it work.”
― Donella H. Meadows, Thinking in Systems: A Primer
What is systems thinking?
System dynamics is the modelling of conditional, imprecise projections of dynamic behaviour
People seldom realize the pervasive existence of feedback loops in driving everything that changes through time. Most people think in linear, non-feedback terms. When we think of education, for example, we think variables are independent, have no causality, and change instantaneously and linearly. Figure 1 illustrates this limited mind model when we think of factors influencing academic success.
Figure 1: Traditional boxed thinking does not take feedback into consideration.
But the system is far more realistically modelled as depicted in Figure 2. There exists a dependence between factors, dynamic causality as the value of one changes the value of another, time delay as changes propagate through the system in a rarely linear way.
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Good teachers increase academic success, but in turn are motivated by the success they observe to perform even better. A good parental pool increases academic success directly by, for example, assisting with homework, while also increasing academic success indirectly by, for example, providing a stable home environment. A good home environment, in turn, enables parents to provide direct support to learners. The elements within a system interact with each other whether directly or indirectly, and influence the trajectory of change within each. This change grows over time in nonlinear ways.
Figure 2: Systems thinking understands the dynamic feedback between elements.
Feedback is the part of a system in which some portion (or all) of the system's output is used as input for future operations. Feedback loops can be either negative or positive. Negative feedback loops are self-regulating and useful for and maintaining an optimal state within specific boundaries. Negative feedback loops are known for being stable, but not especially accurate.
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In contrast, positive feedback loops simply repeat actions that have been effective in the past. The intention of a positive feedback loop is to amplify a desired variable and naturally move the system away from its starting state to a desired state. Problems can occur, however, when the positive feedback loop grows exponentially without any checks or balances.
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Figure 3: Negative feedback exhibits goal seeking behaviour.
Academic performance
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Figure 4: Positive feedback propagates behaviour to exhibit growth.
The combination of positive and negative loops enable us to analyse the observed variable in any system. Complex systems behave in ways entirely different from our expectations derived from experience with simple systems. Because intuition is based on simple systems, people are misled when making decisions about complex systems. System dynamics simulation modelling is the key to making the correct decisions.
Want to learn more?
Visit the System Dynamics Society for more information about system dynamics.
