extend your visual modelling skills through the use of the sign graph diagramming technique explore the dynamic relationship between social, economic and ecological factors whose inter-dependencies will determine the complex dynamics of the future as it unfolds identify points of intervention within this complex system in order to "nudge" the situation towards a more favorable outcome

Outcome - you should be able to:

use the sign graph diagramming technique to develop and communicate a systemic understanding of complex situations
identify feedback relationships as fundamental controllers within systems and as points of intervention to enact change

Aim - Practise the use of diagramming techniques as part of a fundamental shift in interpreting issues – from an assembly of static objects to a network of dynamic relationships

investigated a range of factors that may lead up to the ‘perfect storm’: a combination of interlinked environmental, social and economic crises. explored your personal ecology, extending this to incorporate quality of life and environmental impact aspects. You have done this using a range of verbal, visual and mathematical models.

Our mental models evolve through the process of learning. But this can only be made apparent to others through externalizing those mental models through communicative actions. At its most basic, this may just involve having a conversation, drawing a diagram or writing a piece of text. Learning is at its most powerful when we engage with others through communication to reveal and then contrast our mental models.

Explore and communicate the dynamic nature of feedback relationships within systems. This will involve developing increasingly relational models of the world, i.e. moving away from viewing reality as made up of static and distinct objects, to an awareness of the constant flows within which we are immersed. This is a distinct departure from the classical reductionist approach which compartmentalizes reality into separate disciplines, each of which focuses on narrow bands of organizational, temporal and/or spatial scale.

First, shift away from reductionist thinking and direct attention towards the relationship between components, rather than a focus on the components themselves.

Establish the two fundamental mechanisms through which systems engage in flows of energy, matter and information: positive feedback and negative feedback.

These occur when processes which control the flow and transformation of information, material and energy within systems ‘feed back’ to either speed up the flows/transformations (positive feedback) or dampen these down (negative feedback).

How living systems use these feedback processes to maintain an apparent stability?

Role of information in controlling system behavior.

Two techniques for describing feedback relationships and flows/transformations within systems in a visual way.

Engage in developing a more sophisticated visual model of one of the themes raised in the ‘Powerdown Show’ program.

The sign graph diagramming technique is the ultimate visual modelling approach for revealing positive and negative feedback relationships. Use this technique to first explore, and then communicate, the dynamic nature of the complex situation chosen to be investigated.

The first sign graph we will develop will focus on revealing positive feedback relationships – how a range of factors combine to create an increasingly problematic and unsustainable situation. Once you have developed this first sign graph, you will be asked to create a second sign graph by adding factors and relationships which will introduce negative feedback processes i.e. points of intervention to dampen down the escalating deleterious causes and effects identified in the first sign graph.

Resource

Flows and feedback

Systems thinking: the first step

Analysis: A method of understanding something by dividing it into parts and making sense of the parts.

Synthesis: Trying to understand something by considering its relationship to other things. Also the process of making a whole out of parts.

Object: A discrete entity, or one that is perceived to be so. Used to categorise flows of energy, matter and information. This is especially relevant when these manifest levels of structural and/or process stability. For example, a stone or a flame can be objectified because their material composition, energy levels and capacity to convey information are stable enough over time for categorization.

System dynamics: The study of the patterns of feedback in complex systems.

The processes of analysis and synthesis in conventional thinking are based on the concept of an object.

An object is something that can be clearly distinguished from its environment and can be characterized by its attributes. Attributes enable categorization schemes that are the basis of our normal thinking. So when you look at a particular ecosystem, for example a pond, you find different animals and plants. And if you look at any ‘book of the pond’ you find each animal and plant described in terms of the attributes you can recognize it by: at the first level is it an animal or a plant, if an animal then at the second level is it a fish, or an amphibian, and so on. But this scheme tells you nothing about how the pond functions as a dynamic system.

The first stage of the development of systems thinking recognized that reductionist thinking was flawed and did not enable interconnections and interrelationships to be taken into account. This gave rise to the first idea of a system being a set of interrelated objects. The disciplines of system dynamics, complexity theory and chaos theory all arose from this first step.

Use the ideas in a powerful way to explore the problems raised by the reductionist.

In examining our pond, the most obvious interrelationship between the plants and animals, is that some plants and animals are food for other animals and without the food of course they would die of starvation.

We have started identifying ‘objects’ (a pond and some of its components – plants and animals) and highlighted one relationship (some organisms provide food for other organisms). If we visualize the pond system as flows of energy and matter (food) between objects (plants and animals) then we can start building a picture of the pond system’s structure (the objects and their relationships) and function (the purpose of the various interactions).

We have already identified one function of the pond system – food web support. In other words, a pond sustains the flow of matter and energy through a web of living organisms as one feeds off the other. Each object within the food web could be characterized by a range of attributes describing quantity (e.g. level of biomass) or quality (e.g. relative health). At the same time, we can start linking the objects together so that we can represent the food web support function.

In building a picture of food web support within the pond system, we need to exercise both of our skills in analysis and synthesis. Analysis is needed to identify the various objects. For example, we may want to break down one object (animals) into several objects (herbivores, carnivores, parasites). We can continue doing this ad infinitum: species; age cohorts; individuals; organs; etc. Synthesis is therefore needed so as to not lose sight of the primary aim of our investigation – identifying the objects and relationships that contribute towards the pond system’s food web support. One could consider synthesis as a check on the amount of unnecessary and irrelevant analysis.

Ponds, like all living systems, are not static. A major component of systems thinking is therefore coming to terms with the dynamic nature of systems. The next set of readings will take a closer look at two fundamental types of relationships objects can have: positive and negative feedback. These can be considered the conceptual foundations of systems thinking.

Positive feedback and change

Positive feedback reinforces change.

Simple positive feedback loops are easily illustrated since they are the mechanism through which anything changes rapidly.

The greater the population, the greater the amount of births, and the more births there are, the bigger the population gets and the faster it does so.

Gerald Marten’s example is actually a very real occurrence in many lakes and rivers in Africa, North America, Australia and Asia. The water hyacinth prevents navigation and blocks sunlight from reaching the water, while contributing to the water’s dead biomass, further starving the water of oxygen. A large-scale death of fish results and fishermen can't even get to the few fish that are left. A basic understanding of positive feedback may have allowed fishermen to destroy the few water hyacinths at the beginning of the invasion.

Take, for example, the sale of fair trade and organic products. In order to increase sales of ethical and organic products with limited funding for marketing, companies have to ensure that people who buy the product will tell their families, and friends what a good product they have purchased. That has implications for the quality, price, environmental impact, health benefits and ethics of the product. There will be no word of mouth recommendations if the product does not address most if not all of the previous criteria. But if it does, then increased sales will automatically imply increased word of mouth recommendations, which will further imply increased sales – the positive feedback loop that is required for positive change in society.

All positive feedback must eventually come to an end for, sooner or later, the ‘resources’ on which the rapid change is based will also come to an end. But at the end of this process, there is no guarantee that the situation will revert back to its original state.

Negative feedback and stability

negative feedback : Feedback which operates to reinforce stability. Also called balancing feedback.

stability: Unchanging system structure and/or processes, usually applied in situations where the system's environment is changing.

Example of a negative feedback loop is a simple model of human sleep. Here we can connect the ‘amount of sleep’, the number of hours slept each night, with the ‘amount of tiredness felt’ (see Figure 4.3). This variable is perhaps difficult to define but it is easy to understand what is meant, since you understand your own perception of tiredness. It may be the case that the more you sleep the less you may feel tired, and the less tired you feel the less you may sleep, so again you have a reversal of direction. Each of us has our own particular pattern of sleep, a particular number of hours per night, but for everyone if that pattern is disturbed the tendency is always to revert back to the normal pattern after a few nights.

Negative feedback loops therefore result in stability – so if you want stability you must use this model. One of the first uses in engineering was the famous example of Watt’s Conical Pendulum Governor (Ewing, 1899) the function of which was to stabilize the speed of the steam engine. Any tendency for the speed of the engine to rise was corrected by cutting off the steam, and any decrease by allowing in more steam, thus keeping the steam engine stable, working at constant speed.

Dynamic equilibrium

homeostasis: The dynamic equilibrium through which living systems maintain the conditions for their ongoing existence.

Homeostasis is the term used to describe the dynamic equilibrium that maintains living systems. Homeostasis could be described as the perfect blend of positive and negative feedback cycles in order to maintain living systems.

The limits set by negative feedback mechanisms can be both internal and external. The ‘internal’/‘external’ boundary is a significant one when looking at systems: ‘internal’ refers to properties of the living system itself, while ‘external’ refers to properties of larger systems within which the living system is situated. Identifying the boundaries of a system is not always as simple as this internal/external divide.

The human body also depends on homeostasis; we have a vast range of positive and negative feedback systems to promote our growth in childhood and to maintain us in a healthy state. The levels of glucose, sodium and water in our blood are all regulated by feedback mechanisms. Just a small variation of these compounds would place the growth of a child in jeopardy, if not place their life at risk.

We need to eat in order to provide energy for the various bodily functions which help us to grow and survive, but a sudden influx of nutrients could easily overwhelm the fine chemical balance we have in our bodies. This is the case for people suffering from diabetes. In healthy individuals, the sudden increase in blood sugar levels after a high calorie meal is controlled by the release of insulin. This is a perfect example of negative feedback; the more insulin is produced, the lower the blood sugar level becomes, the lower the blood sugar level becomes, the less insulin is produced, etc., until the body achieves the appropriate blood sugar level. Insulin enhances the capacity of our muscles and liver to absorb the sudden surge in sugars. Individuals with diabetes have lost the capacity to produce sufficient quantities of insulin. They therefore have to inject themselves with artificial insulin after each meal. Without the injections, they risk slipping into a hyperglycemia coma and eventual death as the body cannot control the sudden influx of sugars in the bloodstream.

Living systems and information flows

Information is only meaningful to those systems that can perceive it. In other words, these systems need to have components that act as sensors tuned to the particular form of signal that is arriving. On receiving this signal, these sensors must initiate changes in other flows, which may include flows of energy, matter or more information. Information, therefore, is something that does not already ‘exist’ in the environment. It is a reaction by a living system to flows of energy and matter round it. Flows of information are thus always associated with flows of matter and/or energy and a sensor within the living system. What is more, we not only have to have the sensors to receive that particular form of signal from the environment, but we have to have an internal model which can interpret that signal as information and assess its relevance with regards to its various goals.

In order to survive, living systems have evolved the ability to sense changes and react pre-emptively. On the other hand, inanimate systems like thermostats are only an extension of other living systems. The room temperature is only meaningful to the living system that occupies that room, and the room thermostat is essentially an extension of that living system’s information subsystem.

Representing feedback through sign graph diagrams

It is difficult to depict relational information using verbal communication, and the need for other forms of representation that move away from the linear, ‘drilling down’ reductionist approach.

anitsh / til

Understanding the environment: Flows and feedback #947