1. Introduction to Complex Systems: How to think like nature
A bit presumptuous?
Introduction to Complex Systems: How to think like nature
Unintended consequences: mechanism, function, and purpose
Besides, does nature really think?
Russ Abbott
Sr. Engr. Spec.
Rotn to CCAE
The Aerospace Corporation. All Rights Reserved.

2. A fable Once upon a time, a state in India had too many snakes.
To solve this problem the government instituted an incentive-based program to encourage its citizens to kill snakes.
It created the No Snake Left Alive program.
Anyone who brings a dead snake into a field office of the Dead Snake Control Authority (DSCA) will be paid a generous Dead Snake Bounty (DSB).
A year later the DSB budget was exhausted. DSCA had paid for a significant number of dead snakes.
But there was no noticeable reduction in the number of snakes plaguing the good citizens of the state.
What went wrong?

3. The DSCA mechanism DSCA
What would you do if this mechanism were available in your world?
DSCA
Receive dead snake certificate. Submit certificate to DSCA.
Receive money.
Start a snake farm.
Dead snake
verifier
Catch, kill, and submit a dead snake.

4. Moral: unintended consequences
The preceding is an example of what is sometimes called an unintended consequence.
It represents an entire category of (unintended and unexpected) phenomena in which
a mechanism is installed in an environment, but then
the mechanism is used/exploited in unanticipated ways.
Once a mechanism is installed in the environment, it will be used for whatever purposes “users” can think to make of it …
which may not be that for which it was originally intended.
The first lesson of complex systems thinking is that one must always be aware of the relationship between systems and their environments.
That’s how nature works.

5. Dicrocoelium dendriticum *
D. dendriticum spends its adult life inside the liver of its host. After mating, the eggs are excreted in the feces.
The first intermediate host, the terrestrial snail (Cionella lubrica in the United States), eats the feces, and becomes infected by the larval parasites. … The snail tries to defend itself by walling the parasites off in cysts, which it then excretes and leaves behind in the grass.
The second intermediate host, an ant (Formica fusca in the United States) swallows a cyst loaded with hundreds of juvenile lancet flukes. The parasites enter the gut and then drift through its body. Some move to a cluster of nerve cells where they take control of the ant's actions.
Every evening the infested ant climbs to the top of a blade of grass until a grazing animal comes along and eats the grass—and the ant and the fluke.
The fluke grows to adulthood and lives out its life inside the animal—where it reproduces, and the cycle continues.
* Text and image from Wikipedia.org.
See also, Shelby Martin, “The Petri Dish: The journeys of the brainwashing parasite,” The Stanford Daily, April 20,

6. Toxoplasma gondii * The life cycle of T. gondii has two phases.
* Text and image from Wikipedia.org.
The life cycle of T. gondii has two phases.
The sexual part of the life cycle (coccidia like) takes place only in members of the Felidae family (domestic and wild cats).
The asexual part of the life cycle can take place in any warm-blooded animal.
T. gondii infections have the ability to change the behavior of rats and mice, making them drawn to rather than fearful of the scent of cats.
This effect is advantageous to the parasite, which will be able to sexually reproduce if its host is eaten by a cat.
The infection is almost surgical in its precision, as it does not impact a rat's other fears such as the fear of open spaces or of unfamiliar smelling food.
See also, Charles Q. Choi, “Bizarre Human Brain Parasite Precisely Alters Fear,” Live Science, April 2,

7. Spinochordodes tellinii *
The nematomorph hairworm Spinochordodes tellinii is a parasitic worm whose larvae develop in Orthopteran insects.
When it is ready to leave the host, the parasite causes the host to jump into water, where it drowns, but which returns the parasite to the medium where it grows to adulthood.
* Text and image from Wikipedia.org.
See also, James Owen, “Suicide Grasshoppers Brainwashed by Parasite Worms,” National Geographic News, September 1,

8. Follow the energy/money
Energy (and its proxy money) is fundamental.
Any mechanism that provides access to energy/money/resources is a potential target of unintended consequences.
A niche:
Energy (and its proxy money) is fundamental.
Any mechanism that provides access to energy/money/resources is a potential target of unintended consequences.
A niche: a way of extracting energy/money/ resources from an environment
Example: power is supplied to computer USB ports
Presumably to provide power for USB devices.
The wifi bridge uses the Internet (not USB) Port to transfer data.
But it gets its power from the USB port.

9. Locomotion in E. coli
[E. coli] movements consist of short straight runs, each lasting a second or less, punctuated by briefer episodes of random tumbling: each tumble reorients the cell and sets it off in a new direction.
Cells of E. coli are propelled by their flagella, four to ten slender filaments that project from random sites on the cell’s surface. … Despite their appearance and name (from the Greek for whip), flagella do not lash; they rotate quite rigidly, not unlike a ship’s propeller. …
A cell … can rotate [its] flagellum either clockwise or counter-clockwise. Runs and tumbles correspond to opposite senses of rotation.
When the flagella turn counter-clockwise [as seen from behind] the individual filaments coalesce into a helical bundle that rotates as a unit and thrusts the cell forward in a smooth straight run. …
Frequently and randomly the sense of the rotation is abruptly reversed, the flagellar bundle flies apart and the cell tumbles until the motor reverses once again.
Harold, Franklyn M. (2001) The Way of the Cell: Molecules, Organisms, and the Order of Life, Oxford University Press.

10. Locomotion in E. coli
Cells that are moving up the gradient of an attractant … tumble less frequently than cells wandering in a homogeneous medium: while cells moving away from the source are more likely to tumble. In consequence, cells take longer runs toward the source and shorter ones away.
How can a cell “know” whether it is traveling up the gradient or down? It measures the attractant concentration at the present instant and “compares” it with that a few milliseconds ago.
E. coli can respond within a millisecond to local changes in concentration, and under optimal conditions readily detects a gradient as shallow as one part in a thousand over the length of a cell.
Franklin Harold, The Way of the Cell

11. Mechanism, function, and purpose*
Mechanism: The processes built into an entity. (Difficult to define without circularity.)
The chemical reactions built into E.coli that result in its flagella movements.
The DSCA mechanism.
Function: The effect of a mechanism on the environment and on the relationship between an entity and its environment.
E. coli moves about. In particular, it moves up nutrient gradients.
Snakes are killed and delivered; money is exchanged.
Purpose: The consequence for the entity of the change in its environment or its relationship with its environment.
E. coli is better able to feed, which is necessary for self-persistence.
Snake farming is encouraged?
Wikipedia Commons
Socrates
Philosophical interlude
*Compare to Measures of Performance, Effectiveness, and Utility

12. A significant aspect of the study of complex systems is the clarification of terms
The Periodic Table, Oxford University Press, 2006
Eric Scerri (Chemistry, UCLA) traces the history.
property-bearing
cannot be decomposed
atomic weight
We now use atomic number to characterize element.
We observe phenomena and struggle to characterize them.
Element (Merriam-Webster)
any of the fundamental substances that consist of atoms of only one kind and that singly or in combination constitute all matter.”
emphasis added
We are still at the stage in studying complex systems where we are struggling to characterize the phenomena.
Hence mechanism, function, and purpose and their military counterparts.

13. Nassim Taleb describing a workshop on risk
My first surprise was to discover that the military people thought, behaved and acted like philosophers …
They thought out of the box, like traders, except much better and without fear of introspection. An assistant secretary of defense was among us, but had I not known his profession, I would have thought that he was a practitioner of skeptical empiricism. …
I came out of the meeting realizing that only military people deal with randomness with genuine introspective intellectual honesty — unlike academics and corporate executives using other people’s money.
They just need to go the extra step in realism.
emphasis added
The struggle is to be simultaneously philosophically aware and actionably concrete.

14. It is implemented in Java. Version 4.0 was released September 2007.
NetLogo ( describes itself as “a cross-platform multi-agent programmable modeling environment … for simulating natural and social phenomena.”
It is produced by the Center for Connected Learning and Computer-Based Modeling at Northwestern University. (Uri Wilensky)
It is intended primarily for education (high school, middle school and even earlier) and for qualitative modeling.
It is not a detailed modeling or analysis tool.
It is implemented in Java.
Version 4.0 was released September 2007.
It’s free to download, but it’s not open source.
It produces models that run both as applications and as applets.
It has a large library of models, which also run as both applications and applets, and which can be run directly from the website.

15. Let’s try it File > Models Library > Biology > Ants
Click Open

16. Three tabs Interface tab: control the model.
To run most models, press setup and then go. Press go again to stop the run.
Information tab: documentation about the model
Procedures tab: the model in NetLogo code
Online guide:

17. Simple ant foraging model
Ant rules
If you are not carrying food,
Move up the chemical-scent gradient, if any.
Pick up food, if any.
Otherwise move randomly.
If you are carrying food, move up the nest-scent gradient. When you reach the nest, deposit the food.
population: number of ants
diffusion-rate: rate at which the chemical (pheromone) spreads
evaporation-rate: rate at which chemical evaporates
Turns plotting on/off.
In “to look-for-food” procedure, change “orange” to “blue”.
Implemented chemically in real ants, by software in NetLogo.
After running once, play around with the population, diffusion-rate, and evaporation-rate.
Can you get this picture, with paths to all food sources simultaneously?

18. Two levels of emergence
No individual chemical reaction inside the ants is responsible for making them follow the rules that describe their behavior.
That the internal chemical reactions together do is an example of emergence.
No individual rule and no individual ant is responsible for the ant colony gathering food.
That the ants together bring about that result is a second level of emergence.
Colony results
Ant behaviors
Ant chemistry
As we’ll see later, each layer is called a level of abstraction

19. Two levels of emergence
Presentation
Session
Transport
Network
Physical
WWW (HTML) — browsers + servers
Applications, e.g., , IM, Wikipedia
Colony results
Ant behaviors
Ant chemistry
As we’ll see later, each layer is called a level of abstraction
Notice the similarity to layered communication protocols

20. Complex systems terms
Emergence. A level of abstraction that can be described independently of its implementation.
Examples include the movement of E. coli toward a food source and the gathering of food by ant colonies, both of which can be described independently of how they are brought about.
Multi-scalar. Applicable to systems that are understood on multiple levels simultaneously, especially when a lower level implements an emergent property at a higher level.
E. coli motion and ant foraging are both examples of multi-scalar systems.
Isn’t that true of all systems?
System: a construct or collection of different elements that together produce results not obtainable by the elements alone. — Eberhardt Rechtin
Systems Architecting of Organizations: Why Eagles Can't Swim, CRC, 1999.
System: a construct or collection of different elements that together produce results not obtainable by the elements alone.
Rechtin, E., Systems Architecting of Organizations: Why Eagles Can't Swim, CRC, 1999.
We are in the business of producing emergence