Why you shouldn't always follow the crowd

The Perfect Swarm: The Science of Complexity in Everyday Life

Basic Books: 2009. 288 pp. $29, £13.99 9780465018840 | ISBN: 978-0-4650-1884-0

A school of fish dives and darts to avoid a predator. The motions of each fish appear chaotic, yet as a group they are effective — the school seems intelligent. Our instinct is to look to individual behaviours and to try to assign a leader, yet biologists have shown that collectives can act purposefully without direction. Group skills emerge from the web of interactions between individuals. Similarly, the shininess of gold foil results from the electronic interactions of many atoms; no single atom can be said to be shiny.

To survive in a fleeing crowd, you should make your own way 40% of the time. Credit: S. WONG/STILL PICTURES

A peculiar rift must be confronted in going from the individual to the collective, as science writer Len Fisher explains in his book. The Perfect Swarm focuses on swarm intelligence — the emergence of purposeful, effective and flexibly adaptive group behaviour from interactions between members following simple rules. Fisher explores how this phenomenon unites the behaviour of ants, fish, birds and locusts, and how it links to all areas of complexity science, from neurobiology to ecology. He also embraces the tough challenge of translating the science into practical lessons for everyday life.

Fisher argues that swarm intelligence lies at the heart of human social capability. Our skill in acquiring ideas and technologies from others, now especially through the Internet, means that anything learned by one person can benefit all. Fisher rightly acknowledges the potential dysfunctions of group dynamics. One example is groupthink — the narrowing of vision and closure to competing ideas that is common to committees.

Swarm dynamics touch on many areas of complexity science, from the study of networks to the discovery of meaningful patterns in masses of data. Fisher describes how abstract mathematical entities that mimic swarms are being used to find features in complex data sets, such as images or financial market fluctuations. Much as a flock of birds reacts when encountering a sharp cliff face, the mathematical swarms signal potentially important discontinuities.

Based on a profusion of examples, mainly biological, Fisher draws up rules for living in a complex world. Few books have attempted this; one exception is Harnessing Complexity by Robert Axelrod and Michael Cohen (Free Press, 2000). Fisher explores rules for business, for social networking and for finding the right balance between perfect solutions versus crude but effective rules of thumb. He includes surprising advice, based on computer simulations of crowd dynamics, for surviving in a crowd that is fleeing catastrophe. To benefit from others' possible knowledge of the best route, but to avoid following the herd into a dead end, Fisher suggests that you should “follow the crowd 60 per cent of the time, and spend the other 40 per cent searching out escape routes on your own”.

By focussing wholly on the science of complexity without using narrative ploys to disguise it, Fisher covers a vast subject quickly in a compact book. The Perfect Swarm is a valuable contribution.

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Buchanan, M. Why you shouldn't always follow the crowd. Nature 464, 35 (2010). https://doi.org/10.1038/464035a

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