Intro To Multi Agent Modeling I


This week we're going to look at multi-agent modelling. This approach concentrates on modelling the actions of hundreds of decentralized agents (in the manner of the GoL) that can have relatively complex interactions with each other. The idea is that simple behaviors can result in complex group-level behavior. One of the outcomes of this week is that you'll know how to use NetLogo, a sophisticated general-purpose multi-agent modelling environment.

Questions and tasks

Read the Turtles book (149 pages).

Do you agree with Resnick's whole "era of decentralization" statement? Is he glossing over anything or ignoring a whole series of changes in the other direction? Any examples of decentralization that he left out or that struck you as being a good example (from your life, classes, or research)?

This book uses StarLogo but I prefer NetLogo. NetLogo is a descendant of StarLogo, implementing several refinements to the StarLogo language. You can use StarLogo if you want but I'll be using NetLogo.

When reading through Chapter 3 in Turtles, be sure to have NetLogo and the associated models running (see the "Turtles models in NetLogo" section below) so that you can play with them while you read. The important part of reading this book and having NetLogo available to you is that you begin to get a sense of how emergence works. And the only way that I have seen for this learning to occur is to do it.

Each one of you should take 3/1 (enrolled/not) of the models in Chapter 3 of Turtles and be prepared to discuss it in-depth with the class (no more than 5 minutes each). (Note the models you choose below in the "Turtles model assignment" section.) It would disappoint me if each of you doesn't play with all of these models while you're reading the chapter. Ensure that all of the models get allocated. I am not looking for a formal presentation; I am looking for evidence that you have been thinking and are able to help others learn. You can control my computer and display the model or whatever you want during your talk. Discuss the following in the presentation:

  1. Did you learn anything interesting about these processes by using these models? This can relate to the computer model techniques themselves or insights you gained from the model. You should assume that the other students have read the book and looked at the model briefly. Your job is to investigate the model in more depth and to facilitate the learning and discussion process.
  2. Given our discussion from the first few classes, what reasons do you think there are for creating and running and investigating this simulation? How might the models you investigated be made better science?


  1. Turtles, Termites, and Traffic Jams: Explorations in massively parallel microworlds, by Mitchell Resnick. MIT Press, 1997.
  2. NetLogo community models: These models are contributed by the community and aren't official models (whatever that means). On the other hand, some of these models are very interesting and applicable to this seminar.
  3. More resources
    1. "Aspects of Complexity in Life and Science", by Claus Emmeche, Philosophica, 59(1):41-68, 1997.
    2. "An aesthetic of turbulence: The works of Net Kahn," by David Mather.
    3. "Complexity and scientific modelling", by Bruce Edmonds, Foundations of Science, 5(3):379-390, 2000.
    4. Traffic simulation
    5. Boids and bird flocks

Turtles models in NetLogo

  • Slime Mold (p 50-59): Biology/Slime
  • Artificial Ants (p 59-68): Biology/Ants
  • Traffic Jams (p 68-74): Social Science/Traffic Basic
  • Termites (p 75-81): Biology/Termites
  • Turtles & Frogs (p 81-88): Social Science/Segregation
  • Turtle Ecology (p 88-95)
  • New Turtle Geometry (p 95-103): There's no direct translation of this model but there are a lot of related ones in the model library under "Mathematics".
  • Forest Fire (p 103-110): Earth Science/Fire
  • Recursive Trees (p 110-116)

Turtles model assignment

If you're taking the class for credit, sign up for three of these models. If auditing, sign up for one.

Model Students
Slime mold Suresh
Artificial Ants Suresh
Traffic Jams Andrea
Termites Suresh
Turtles & Frogs Mins
Turtle Ecology Andrea
New Turtle Geometry student
Forest Fire Andrea
Recursive Trees student

Notes if you use NetLogo

NetLogo, while a descendant of StarLogo, differs in many small ways from its ancestor. However, many of these changes are improvements rather than change for change's sake (in my opinion, anyway). Further, and pertinent to this class, the StarLogo models discussed by Resnick in Turtles are all available in NetLogo.

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