Saturday, July 11, 2009

Conceptually rich but unnecessarily complicated

Complex and Adaptive Dynamical Systems: A Primer

by John H. Miller and Scott E. Page (2007)

Complexity is a hot subject. Unfortunately, the language of dynamical systems theory is advanced mathematics, which means that most of the available literature is not readily accessible to lay readers. Educated nonspecialists are left with few options aside from the occasional overview which, typically, does not delve too deeply into the subject matter. Given this state of affairs, Miller and Page’s book would seem to be a godsend.

A stated aim of the book is that of providing a “clear, comprehensive, and accessible account of complex adaptive social systems” for “both academics and the sophisticated lay reader.” Insofar as comprehensiveness, the authors deliver. Readers are first offered preliminary discussions on complexity in social worlds, modeling, and emergence, followed by a more detailed treatment of computational modeling as a tool for theory development and agent-based objects as the recommended means to explore complex adaptive social systems. Then a basic framework of agent-based systems is presented, followed by discussions of unidimensional complexity models and the edge of chaos, social dynamics, evolving automata, and organizational decision making. These topics are largely illustrated with the authors’ previously published models. Finally, conclusions are derived regarding the book’s central theme: the “interest in between” as it pertains to complex social systems (which tend to fall in between the usual scientific boundaries). Two appendices bring up the rear: an agenda for future research in complex systems and an outline of best practices for computational modeling. The thematic coverage is ample and varied, excellent for a general introductory work on social complexity.

Insofar as clarity and accessibility are concerned, however, I find myself in disagreement with the book’s blurbs. Much of the mathematical formalism has been expunged from the discussions, yes, but that by itself does not guarantee enhanced communicability. The logic of the arguments, which in this field is considerable, must now be conveyed by other means, either verbal or visual. The authors do make an effort to explain in words the basic concepts when they begin a new topic. But when they proceed to discuss an actual model, they shift gears. Instead of explaining or illustrating in detail the model’s functional intricacies, they switch to summarizing their findings and present a table or figure that encapsulates the model’s results. Repeated readings of the text are almost always necessary in these cases, but understanding does not always automatically ensue. This approach does not appear to contribute to the goal of making the models “as simple and accessible as possible.”

This situation is not due to writer’s oversight but to a deliberate choice. Prior to discussing their first example model (a computational version of Tiebout’s model), the authors state: “Rather than fully pursuing the detailed version of the model we just outlined … here we provide just an overview.” Fateful words which amount to an announcement of their modus operandi, as the subsequent instances demonstrate. Caveat lector. The reader is also assumed to possess a working knowledge of such things as game theory, elementary combinatorics, and statistics, among others. So brush up on the basics and stay close to a search engine.

Reading this book takes time and some effort; it is not a breezy read. One never gets to see an actual piece of code or even pseudocode, which one would normally expect in an introductory book on computational modeling. The reader is left in a vacuum as to the mechanics of implementation. Still, it is a good book in terms of its conceptual content. However, the inconsistency between the stated aim of providing clarity of exposition at an introductory level and the actual product the reader interacts with detracts from the book’s overall quality. It seems like we are still waiting for the canonical text on complex adaptive social systems.

Note: If you are looking for a general overview of complexity theory intended for a lay audiece, I would suggest Melanie Mitchell’s Complexity: A Guided Tour. It is excellent. At the other end of the spectrum, if you’re heavily into power math, consider Complex and Adaptive Dynamical Systems: A Primer (Springer Complexity) by Claudius Gros. It is rigorous.

Zahid

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