Emergence 2006
Reviews of Relevant Books
On Serendip

In his book Turtles, Termites, and Traffic James, Mitchel Resnick introduces the ideas of decentralized systems that result in different layers of emergent phenomena. He mostly addresses the question of why decentralized systems are important, and how we can teach decentralized thinking to children, and does not really write about how emergent systems work, or why. This book is an effective introduction to the basic ideas of emergence from an educational standpoint. Resnick divides the book into five sections: Foundations, Constructions, Explorations, Reflections, and Projections.

In the "Foundations" section, he describes the trend towards decentralization in five areas: organizations, technologies, scientific models, theories of mind, and theories of knowledge. He refers to the dissolution of the USSR and the decentralization of IBM as examples of the trend away from centralized power structures. However, I do not entirely agree with his claim that organizations are become more decentralized; when I look at mega-corporations like PepsiCo and Disney, I see gigantic hierarchical structures that are constantly growing and acquiring new companies. On the other hand, he is correct about new academic theories. New ideas in biology, cognitive science, and physics are resting more and more on decentralized self-organizing systems.

Moving onto "Constructions," he describes StarLogo, the system he created to help students design and observe decentralized systems. He believes that this will help the students understand these systems much better than if he just explained how they work or demonstrated them. He quotes Confucius: "I hear, and I forget. I see, and I remember. I do, and I understand." To me, this raises questions about the usefulness of this book; most of it consists of telling us about certain Starlogo simulations, and while Resnick provides Internet links to let us try the simulations ourselves, these links no longer work. He emphasizes that in StarLogo, the patch system makes the environment more important, and the turtles make object-oriented programming more intuitive to students.

In the "Explorations" section, Resnick shows us nine examples of simplified simulations of real-world phenomena that result in emergent behavior. He starts with slime mold aggregation using diffusing pheromones, and then goes through ant foraging behavior, traffic jams, termite wood chip collection, segregation, predator/prey ecology, forest fires, and trees. There is also a section on geometry, which seems really out of place in this book; it does not really have anything to do with decentralized systems or emergent behavior. All of the examples are fairly interesting and well-explained, but it is never clear why they are important except as tools to help students understand the basic ideas behind decentralized systems.

The "Reflections" section discusses why the "centralized mindset" is so prevalent, and provides "heuristics" for thinking about decentralized systems. Resnick urges us to keep in mind that positive feedback can be constructive, randomness can help create order, it is important to separate different levels of behavior, and the environment plays an important role in agent behavior.

The last section, "Projections," is only two pages. Resnick argues that in order to overcome the centralized mindset in children, it is important to integrate education about emergence and decentralized systems into the academic curriculum from an early age.

Overall this book is an effective introduction to the basic ideas of decentralized systems and emergent behavior for someone with little experience in the field, or who is interested in teaching these ideas to students. It felt rushed towards the end; the examples and sections kept getting shorter, until the final chapter was only two pages long and had almost no content. It would also have been much more effective if the website it linked to still existed, so that readers could try out the simulations it referred to. To me it was most interesting that the book was written in 1994, and we are still running the exact same simulations in 2006. It makes me wonder if Mitch Resnick was just far ahead of his time, or if the field has really been essentially stagnant for the past twelve years.


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