Escaping the Complexity Dilemma
Barry Newell & Katrina Proust
The Australian National University
The Complexity Dilemma
1. A feedback system is a set of parts (elements, actors)
that interact to constrain each other’s behaviour.
2. The behaviour of such a system emerges from the
interactions between its parts.
3. Therefore, you can’t optimise the behaviour of the system
by optimising the behaviour of the parts taken in isolation.
4. You have to study the system as a whole.
5. But, when you try to do this, you are overwhelmed by the
complexity of the system. The behaviour appears to be
unmanageable.
Escaping the Complexity Dilemma
One way to escape the complexity dilemma
is to look for shared features or attributes
between things which, at first sight, seem to
be very different.
For example, if a number of apparently
disparate behaviours can be shown to be
just different versions of a single behaviour,
there can be a significant reduction in the
apparent complexity of the observed world.
The Challenge Activities
In system dynamics
terms, your challenge
was “construct a
generic dynamic
hypothesis”.
1. Constructing freeways
2. Substance abuse
3. The war on terror
4. The war on drugs
5. Taxing alcopops
6. Urban renewal
7. Constructing flood-control levees
8. Engineering the climate
9. Intensive irrigation development
10. Spraying ragweed with broad spectrum herbicides*
11. Using mould ‘killers’ in bathrooms*
12. Introducing shrimp to feed freshwater salmon*
13. Planting wheat on the Great Plains*
System Dynamics
System dynamicists construct models, mental or
formal, that explain why things behave the way that
they do). Causal theories.
All such theories attempt to isolate invariant
behaviours in the world. That is, behaviours that
are observed in many different contexts and at
many different times. Generic behaviours.
All such theories attempt to provide simple
explanations for these generic behaviours.
Powerful explanations.
System Dynamics
“The feedback loop is the fundamental
building block of system dynamics
models, and is the basic unit of analysis
and communication of system
behaviour.”
George Richardson, 1991, Feedback Thought in
Social Science and Systems Theory, p. 4.
System Dynamics
Only two types of feedback:
Reinforcing
Positive
Balancing
Negative
System Dynamics
Only two types of feedback:
Positive feedback is not necessarily good.
Negative feedback is not necessarily bad.
System Dynamics
Only two types of feedback:
Feedback can cause counterintuitive behaviour.
System Dynamics
Only two types of complexity:
Detail Complexity (Combinatorial)
Examples: Scheduling commercial aircraft
movements at a large airport. Scheduling
classes into classrooms, particularly
when there is significant course flexibility.
Dynamic Complexity (Feedback)
Example: The Ragweed Problem
The Ragweed Problem
The Ragweed Problem
But … leads to more ragweed next year. Why?
The Ragweed Problem
The Mould Problem
CHOICE
Magazine
Shonky Awards
2012
It’s habit forming
The Mould Problem
Salmon and Shrimp
Spencer et al. 1991, BioScience, 41, 14-21.
Salmon and Shrimp
Wheat on the Great Plains
Fixes That Fail
Generic
Structure
System Archetype
Fixes That Fail
Generic
Structure
System Archetype
Fixes That Fail
System Archetype
Signature Behaviour
System Traps and Opportunities
Meadows considers System Archetypes to be
“system traps and opportunities”.
Traps – because they can cause unexpected
outcomes, such as ‘fixes that fail’ – barriers to
effective policy implementation.
Opportunities – because, once recognised, they
can help isolate powerful ‘leverage points’ –
places in a system where small pushes can lead
to large changes.
Meadows, D.H., 2009, Thinking in Systems (Earthscan:
London)
Fixes That Fail
Leverage Point
Fixes That Fail
Leverage Point
Fixes That Fail Template 1
System Archetype
Fixes That Fail Template 2
System Archetype
Apply the Archetype
The Fixes That Fail archetype can be used to
structure a discussion of the similarities of the
activities on the challenge list.
1. Working in groups, develop an explanation of the
failure of one or more of the ‘fixes’ (Activity 1 to 9,
inclusive). You can use the templates provided.
2. Select one of your archetypes for presentation
and discussion.
3. Nominate a group member to make the
presentation.
Further Reading
Meadows, D.H., 2009, Thinking in Systems: A Primer
(Earthscan: London). A good general introduction to system
thinking and system dynamics. Easy reading.
Senge, P., 1990, The Fifth Discipline: The Art and Practice
of The Learning Organization (Random House: Sydney).
The first published discussion of system archetypes, which
he calls “Nature’s Templates.” Easy reading.
Sterman, J.D., 2000, Business Dynamics: Systems Thinking
and Modeling for a Complex World (Irwin McGraw-Hill:
Boston). A thorough discussion. Do not be misled by the
word ‘business’ in the title—this is a solid textbook that will
be valuable to readers in all disciplines. ~1000 pages.