The New Science of Synchrony
In Sync: The Emerging Science of Spontaneous Order, scientist and mathematician Steven Strogatz takes the reader on a wild ride through more than a century of observations, theory and scientific research on the fascinating subject of synchronization in nature. Synchronization is a universal phenomenon that pervades many processes in the natural world and society. Strangely enough, most of us, most readers of this article, for instance, may not even be aware of Sync when it is happening around us. Flocks of birds fly together, keeping a uniform distance from one another, in a display of natural synchronization. Shoals of fish avoid obstacles and predators alike as they commute the grand waterways of our seas. Your heart beats unerringly a regular number of times every minute, thanks to pacemaker cells that work in synchrony from when you were a foetus in your mother’s womb, until the very last moment of life. When you see a certain kind of picture with similarly contrasted objects in specific positions, your brain tries to recognize a face from the image in a simultaneous, synchronized firing of neurons from your brain’s visual cortex. In the Olympic games and during the national parades, team based synchronized behaviour is on display in swimming events and in group dances alike. Traffic moves along everyday in our cities, where disparate sizes of vehicles ranging from bicycles to trucks – agents of essentially selfish commuters – collaboratively travel together to get to their respective destinations. Sync takes a look at all these phenomena at their very fundamental level. The book also touches upon the lives and work of researchers ranging from Victorian era scientists through the greats of the nuclear and space ages, to contemporary scientists that inhabit the same internet as you and I.
All stories of scientific research begin somewhere, usually from one or a few individuals who are party to exceptional experiences, and also have the insight and wherewithal to see the value in these exceptional experiences and not consider them trivial. Christiaan Huygens – famed astronomer; the Cassini Huygens Titan planetary probe is named for him – noticed on a long voyage by sea, that clock pendulums placed next to each other would automatically synchronize their oscillations. Even when you perturb them so that, for instance, one would approximately swing left even as the other swings right at a completely different speed, they would eventually start swinging together in perfect synchronized opposition. Kurt Wiesenfeld of Georgia Tech, a scientist associated with the renowned scientist Per Bak in his studies of self organizing systems in the 1980s, reproduced Huygens’ pendulum experiment in recent times and understood the underlying conditions for such pendulum synchronization to occur. Per Bak himself spent a large part of his career studying self-organization in complex systems, which is a pervasive order in nature that is related to the more fundamental subject of synchronization at some level. Decades before him, Edward Lorenz played with climate models that turned out to be representations of nonlinear dynamical systems, and decades before Lorenz, Lucien Poincare cogitated the first principles of what we now know as nonlinear dynamics in studies of topology. In a sense, Huygens’ child-like speculation on why pendulums synchronize, led to entire generations of scientists interested in why oscillators synchronize, and whether there was a greater order in nature. It was that seed of speculation that has led us to this self-similar tree of knowledge, where we see the same patterns of synchronization and self-organization in disparate things, whether in natural or in synthetic processes.
Before pendulums were studied in the lab in times of scientific speculation, humans have observed synchronization in various forms during the course of our evolution, and inevitably, become part of many phenomena that require synchronization. We’ve seen deadly locusts eat our crops and stampedes of animals (and humans) kill humans and animals alike. We’ve seen shoals of fish swim together or avoid obstacles and predators by collective intelligence. Each of these phenomena require communication by following simple rules in the space they navigate. By following simple rules, this large number of agents leads to complex behaviour and interesting results. An example of time based synchronization that is handled in the book, at the very beginning, is that of the fireflies on the banks of rivers in Thailand. Millions of fireflies exhibit time synchrony as they flash, in a kind of resplendent bioluminescent theatre. If it is as spectacular as it is described in the book by Strogatz, I hope to see it someday with my own eyes. Strogatz describes our ability to be surprised by such behaviour succinctly, when he suggests that humans are used to thinking in terms of direct cause and effect, and in terms of chains of command. Much scientific beauty remains unrecognized and unacknowledged, because our own limited imagination and because of how we see things with a limited scientific lexicon.
London’s Millenium bridge was famously party to the phenomenon of synchronization in a rather destructive form. On the day of its inauguration, the bridge featured hundreds of commuters stepping side to side as they walked forward, in an effort to maintain their balance on the bridge. Starting from a small sideways perturbation to the bridge, the oscillation developed into a self-reinforcing “emergent behaviour” that stressed the bridge enough to send off warning signals. The bridge was subsequently closed to the public before the engineers who worked on the structure remedied the problem. This and the Tacoma Narrows bridge, a favourite example for many of how not to design bridges for the kinds of wind loads it experienced, are touched upon in Strogatz’s book. Apart from this much studied structural engineering example, the book takes us on a tour to the surreal and sometimes unnatural-sounding phenomenon of superconductivity as discovered by Heike Kamerlingh-Onnes in the 1920s, in ultra low temperature substances. Everything about superconductivity seems counterintuitive – electrons have no need to march in step and not offer current any resistance – and yet, experiments proved superconductivity’s existence. In his narrative, Strogatz takes us through the work of Brian Josephson and electrons that pair up in “Cooper pairs”. The antecedents of this work lie in the work of one of India’s greatest sons: Sathyendra Nath Bose, who teamed up with Albert Einstein to propose the Fermion-Boson framework before Josephson’s research. Josephson’s contributions and his life, especially the tragic last phase of his scientific career are described in some detail. The reader is made to wonder whether the temerity to study the most fundamental principles of the universe comes only with the bravado to consider all ideas and sundry, with an open mind, and entertain even the strangest sounding ideas as long as they were plausible, and sometimes, even when they were implausible. How wide is the thicket of uncertainty that you wander, before you reach certainty, and if this is not the true spirit of inquiry, what is? If anything, Bose’s idea was itself dismissed by most scientists until Einstein came along to take it seriously. Science books can have souls. This discussion on superconductivity and the passages towards the end, where the beauty of sync notwithstanding its complexity is discussed, are where this particular book is revealed to have one.
Some of the enduringly beautiful passages in the book concern the early work of Edward Lorenz, Boris Belusov, Benoit Mandelbrot and other pioneers of chaos theory. Lorenz was a climate scientist – the kind of scientist you wouldn’t associate with big scientific breakthroughs in the 1960s. And yet, from his work and Belusov’s in the Soviet Union (Belusov’s rather tragic story makes for engaging reading in the book), later scientists developed the foundations of chaos theory and nonlinear dynamical systems. It is in the study of Belusov’s work that we are introduced to Arthur Winfree, a colourful and maverick researcher in the field, and a recipient of the Macarthur Genius award, one of the highest US awards for intellectual achievement. Winfree’s work inextricably involves Strogatz himself. As one of Strogatz’s inspirations for his work, Winfree sets up the context for Strogatz’s own research into nonlinear dynamics and chaos, and in the process, connects Belusov’s chemical reactions to trefoils – a unique class of geometric curves, in a series of experiments. Strogatz’s personal takes and his accounts of his growth as an experimental scientist here make for interesting reading. (In another context – that of cellular automata, Belusov’s work is shown to have similarities with the work of another genius who was visited by tragedy, Alan Turing, in an award winning BBC documentary, “The Secret Life of Chaos”.) The book also discusses Benoit Mandelbrot and the Mandelbrot fractal, which has become a sort of rubber stamp for modern day physics, like the stereotypical atom insignia with three electrons pervaded the nuclear age. Mandelbrot was an utterly unconventional, being a self-taught mathematician who haunted the halls of IBM in its heyday. Drawing upon old studies that started with Huygens’ contemporary, George Cantor (of Cantor set fame) and Swedish mathematician Helge von Koch’s eponymous curve, he mated computers with self-similar patterns and coined the term “fractal”, which has entered regular use in English. His work explained everything from the shapes of coastlines to the patterns of ferns and trees and many of the commonly observed, intricate shapes in nature. His book “The Fractal Geometry of Nature”, like James Gleick’s book on Chaos, Ron Eglash’s TED talk on African fractals, or the Xaos and FractForge fractal generator programs on old Linux distributions, had an incredible impact on how I saw the world, when I picked it up. Few ideas change your worldview and clear the mind’s cobwebs of old ideas and instigate new curiosity. Path breaking science like the science of complex systems surely has this capacity, given its depth, meaning and the broad swath of interdisciplinary problems its studies are applicable to.
The book engagingly discusses Strogatz’s own work as well. What does the synchronized beating of millions of fireflies or the behaviour of Josephson pairs of electrons in a superconducting liquid have to do with how well your friends are connected in your favourite social network? Quite a lot more than is immediately apparent, perhaps. Steven Strogatz has done important research that helps us understand how groups of agents behave. When that cat video goes “viral”, or when some earthquake survivor gets help thanks to social media, or when news spreads from its point of origin at some newsroom and transforms opinion across social networks, or indeed, when AIDS and similar epidemics spread across communities and countries, small world networks are at work. Recent studies into networks of terror outfits affirm similar principles of “small world-ness”, or, in the words of Albert Barabasi, “scale free” networks, apply. Duncan Watts, one of Strogatz’s collaborators, wrote a rather interesting book called “Six Degrees” that essentially delineated the Kevin Bacon game from a scientific view point. By examining the social connections we have, we can understand how the human race on this planet at large is connecting together and behaving as one “super organism”. Sync covers the Milgram experiment and Watts’ original research in the chapter on Small World Networks. Nature, it would appear, is not entirely random about the way it organizes networks, but exhibits a parsimonious behaviour somewhere between order and chaos – true order being a uniformly arranged social network, and true chaos being a social network with little semblance of any periodicity of any kind. Strogatz, Watts and MEJ Newman published a seminal paper in the Nature journal in 2006, which I read in around 2008 with awe. The authors describe random networks, small world networks and clustering. For those who haven’t read Six Degrees (and for everyone on Facebook or Twitter), this particular chapter is sure to drive home the importance of Sync to our new reality.
In conclusion, Sync: The Emerging Science of Spontaneous Order, is a must read for those interested in contemporary science and for youngsters interested in doing scientific research. The book connects the past to the future, in an unending chain of scientific discoveries that lend increasing clarity to the complex world we inhabit. A theme that pervades the book, from the very start of it, is the creation of simple models that explain complex observations. I can’t think of one more pervasive need to read this book than to peer into the minds of people who provide simple explanations for the seemingly complex nature of the problems they explain. The book is a product of new ways of looking at the world that have their roots in timeless and childlike speculation from centuries ago. The science described here and research that stems from the work described will probably take us to the next scientific frontiers.
Other related books:
- Chaos: Making A New Science, James Gleick
- Six Degrees: The Science of a Connected Age, Duncan Watts
- An Introduction to Complexity, Melanie Mitchell
- Linked: The New Science of Networks, Albert Laszlo Barabasi
- Introduction to Nonlinear Dynamics and Chaos, Steven Strogatz