A Cambridge-based institute takes a complex systems approach in a wide range of areas, from evolutionary biology to social behavior.

Mason Inman

In the process of designing more-efficient cell-phone networks, we could learn something about how the brain develops. That’s the message from some of the latest research coming out of the New England Complex Systems Institute (NECSI) in Cambridge. The study, in the September issue of Europhysics Letters, shows how cutting away unnecessary links in a broadcast network allows messages to be transmitted faster and with fewer node-to-node “hops,” just as a developing brain prunes connections between neurons in order to process information more efficiently.

Comparing cell-phone networks with brains isn’t just an analogy, says Yaneer Bar-Yam, president of NECSI. A major goal of NESCI is to formalize methods of modeling and analyzing networks and other complex systems, and to find general principles that apply to many kinds of systems, from genes in a genome to the members of a species interacting within a population. NECSI is one of a few independent institutes that are fostering a complex systems approach to a wide variety of topics, from networks and evolution to business management and ethnic violence.

“Collective behaviors occur in every system we know about—physical, chemical, biological, social, engineered,” says Bar-Yam. The same mathematical tools and approaches can be applied to these varied systems, he adds, because ”the principles underlying collective behaviors are universal.”

Understanding these principles not only lets researchers borrow mathematical tools from other fields—it can also help solve tough problems that simpler approaches couldn’t grapple with, such as how cooperation and altruism can arise through evolution.

Faculty network

NECSI’s office is in an old Victorian building just south of Harvard. It’s well situated since nearly all of its faculty are also professors at local universities, including Harvard, MIT, Boston University, and Tufts. The institute has 10 graduate students and postdocs, half of whom are affiliated with schools in the area.

“NECSI was created because of the need for interdisciplinary and interinstitutional collaboration and research that is difficult to place within a departmental context,” Bar-Yam says.

The institute, founded in 1996, organizes the International Conference on Complex Systems, which will be held later this month in Quincy, MA. It also runs intensive one- or two-week-long workshops to train researchers on how to study complex systems.

Growing interest

Interest in the study of complex systems has increased in the last seven or eight years, when researchers began developing more quantitative tools to analyze the massive amounts of information pouring out of genome sequencing projects and gene expression studies. Now complex systems approaches are trickling into other fields.

For example, in evolutionary biology, NESCI researchers have shed light on old problems by taking into account the complexity of populations. In a 2005 paper in the Proceedings of the National Academy of Sciences, Bar-Yam and Justin Werfel (then at MIT, now a postdoc at Harvard) showed how selection often acts on whole groups of organisms, rather than on individuals. Such ideas were lambasted for the past few decades, but a systems approach showed when and where such cooperation can arise—and Bar-Yam argues it’s far more common than biologists thought.

“Most evolutionary models are founded on simple relations [between organisms],” says David Sloan Wilson, a biologist at Binghamton University. But Bar-Yam showed that patchiness can develop in populations—something that the usual models can’t capture very well. By finding ways of addressing these situations, Bar-Yam and colleagues ”have made an important contribution to multilevel selection,” Wilson says, referring to how selection can occur at both the individual and group level.

Adoption of the complex systems approach is still at an early stage, but is growing, Bar-Yam says. “It is so fundamental, it has got to be part of how we think about these systems.”