The Perfect Swarm: The Science of Complexity in Everyday Life

by Len Fisher

Simple Rules for Complex Collective Behavior (Arising From Simple Rules), February 18, 2011

By

Fort Hugo "Hugo Fort" ((Montevideo, Uruguay)) - See all my reviews

This review is from: The Perfect Swarm: The Science of Complexity in Everyday Life (Hardcover)

The Perfect Swarm is a thought provoking book that does a very good job in transmitting the state of the art and the beauty of the science of Complexity, more a collection of ways of thinking -that have developed from different fields emphasizing concepts like holism, emergence, innovation, adaptation, and self-organization- than a well established theory.

The book displays a plethora of interesting and sometimes bold ideas on complexity, illustrated by well selected examples taken from everyday life and covering a wide range of fields. Written in a pop science style that makes complex ideas accessible to the lay person, it touches crucial issues either avoiding technical terms or explaining them in a simple (but not simplistic) way. The main topic is a fundamental one in science in general, namely the emergence of complexity in nature out of simple laws. Fisher explores this problem in the case of animal groups, from insects to humans, in order to better understand how their collective complex behavior arise from simple rules of social interaction between individuals.

A central concept is swarm intelligence : "Swarm behavior becomes swarm intelligence when a group can use it to solve a problem collectively, in a way that the individuals in the group cannot." Swarm intelligence is a paradigmatic example of self-organization of complex systems that requires no leader or central planning. The author argues that self-organization needs the complementary roles of positive and negative feedbacks: the former produce "chain reactions" and work as amplifying factors, while the latter act as regulatory mechanisms. This mathematics of bum and bust is well exemplified by the popular logistic equation from population ecology. In fact this is the only equation that appears in the book, so Fisher took seriously the advice that "each equation halves the audience".

I found particularly interesting the discussion of chapter Five, on whether choosing the majority opinion or some sort of average opinion. Besides its obvious relevance to decision making in modern democracy, the author analyses its usefulness in estimating quantities and finding optimal solutions. The conclusion is simple: For problems that involve figuring out the value of something (like the number of jelly beans in a jar or the weight of an ox), that is, state estimation in technical parlance, the best solution is to take the average of all answers. On the other hand, for problems that involve choosing the right answer from among a small number of possible alternatives, majority opinion serves better. Indeed the author supports this claim with two theorems: Page's Diversity Prediction Theorem for the first situation and Condorcet's Jury Theorem for the second.

This problem of decision making in complex situations with incomplete information, in a finite time, and with a finite budget is addressed again later on. Since in the real world, search for solutions to problems costs time and money, there is a point where the expected costs exceed the benefits and further search is no longer justified. So our minds rely most of the times on simple heuristics that are more rapid but usually less accurate than strategies that use more information and computation. Indeed "Homo heuristicus can often outperform Homo sapiens" . The alternative to simple heuristics is to search for patterns within the complexity. The problem is that noticing real patterns in the often apparent chaos of nature, and distinguishing randomness from complexity, can be a really complicated business.

In summary I strongly recommend this book to anyone interested in complex systems in general and concepts like emergence, adaptability and in a unifying perspective about the organizational principles of swarm intelligence to solve complex tasks by integrating simple individual behavior for the well-being of the whole group. I learned from both the contents and arguments presented by the author and I really enjoyed reading this book.

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**"For every thousand hacking at the leaves of evil, there is one striking at the root."**David Thoreau (1817-1862)

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