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Since the last major ice age, populations of large animals have dwindled. These declines have directly affected climate change, wildfires, and natural resources. A March 17-19 working group brings together historical ecologists, conservation biologists, computational modelers, and archaeogeneticists to explore these impacts further and develop new tools for predicting ecosystem resilience and preventing future megafauna loss.

Using a variety of analogy puzzles, SFI researchers have shown that the reasoning abilities of OpenAI’s GPT-4 model fall short when faced with small changes. Recognizing the limitations of these tools is critical to knowing when and to what extent they can be trusted.

In a recent study in Physical Review Letters, SFI Complexity Postdoctoral Fellow Aanjaneya Kumar and colleagues show that the margin of victory for any election can be predicted solely by the voter turnout.

Medieval friar William of Ockham posited a famous idea: always pick the simplest explanation. Often referred to as the parsimony principle, “Ockham’s razor” has shaped scientific decisions for centuries. But lately, incredibly complex AI models have begun outperforming their simpler counterparts. A new paper in PNAS argues that by relying too much on parsimony in modeling, scientists make mistakes and miss opportunities.

Applications for the third Complexity Global School (CGS) are now open. The school will be hosted at Universidad de los Andes in Bogotá, Colombia, and applicants from all countries are eligible to apply. Supported by the Omidyar Network and the Ford Foundation, the school is free, with expenses covered, for all admitted students. Applications are due by March 16, 2025.

Cultural traits — the information, beliefs, behaviors, customs, and practices that shape the character of a population — are influenced by conformity, the tendency to align with others, or anti-conformity, the choice to deliberately diverge. A new way to model this dynamic interplay could ultimately help explain societal phenomena like political polarization, cultural trends, and the spread of misinformation. 

Over the past three years, SFI has hosted an annual Complexity-GAINs school — two-week-long programs organized around a theme for Ph.D. students — in different locations in Europe. The third and final school, focused on ecological resilience and persistence, was held last October in Sète, France.

Half a century ago, economic research took a little-noticed yet dramatic departure from the study of concepts most people might be familiar with from Econ 101. The field shifted from an almost exclusive focus on market transactions and government policies to include societal interactions for which supply-and-demand models don’t work. A new paper in Economics Letters uses a machine-learning technique to document this shift away from state-related topics toward a focus the authors term "civil society."

Knowing only the building blocks of our own biosphere, can we predict how life may exist on other planets? What factors will rein in the Frankensteinian life forms we hope to build in laboratories here on Earth? A paper in Interface Focus co-authored by several SFI researchers takes these questions out of the realm of science fiction and into scientific laws.

On December 19, the SFI Press published Volume 4 of Foundational Papers in Complexity Science. Following the publication of Volumes 1 and 2 in May and Volume 3 in September, this concluding book contains papers published between 1989 and 2000 — an era when complex-systems science had become a fledgling field of study in its own right. Hardcover and paperback versions of each book are available globally at cost.

A significant body of research has investigated why, as city populations grow, so do violent crime, contagious diseases — and per-capita GDP. A new paper now finds that cities with strong interconnectivity show a marked economic benefit, even beyond normal scaling.

Multi-scale complex systems are ubiquitous and also notoriously difficult to model. In disturbed systems, conventional bottom-up or top-down approaches can’t capture the interactions between the small-scale behaviors and the system-level properties. SFI External Professor John Harte and his collaborators have worked to resolve this challenge by building a hybrid method that links bottom-up behaviors and top-down causation in a single theory. 

Organisms that respond quickly to changing environments have an advantage over those that don’t. However, reacting too quickly wastes time and energy in tracking meaningless environmental changes. A new study presents a mathematical model for optimal learning in a changing environment.

A recent study by SFI Complexity Postdoctoral Fellow Katrin Schmelz and coauthors explores various scenarios when it may be beneficial to stand out and when it might be better to blend in. 

Stephan Mertens passed away on October 9, 2024, at the age of 62 after a seven-year battle with multiple myeloma. At the time of his passing, he was a Professor of Theoretical Physics at Otto-von-Guericke University Magdeburg in Germany and an External Professor at the Santa Fe Institute.

Every other month, the subscription-based indie press ISOLARII publishes a single book. ISOLARII’s distinctive palm-sized volumes offer thought-provoking texts on exquisitely crafted pages. Their newest release — a 120-page reprint of science-fiction writer Philip K. Dick’s 1978 speech “How To Build A Universe That Doesn’t Fall Apart Two Days Later” — includes an introduction by SFI President David Krakauer. 

The emergence of new viruses is often unpredictable, jumping as they might from infecting one species to another. A November 12–13 working group organized by SFI External Professor Santiago Elena convenes to identify which factors are important to emerging viral pathogens. 

Fifty-six participants from six continents met at SFI for the 2024 Postdocs in Complexity Global Summit on September 23–26. Participants shared knowledge and skills, discussed challenges, deepened existing research collaborations, and developed new project ideas.

SFI's Past President and Distinguished Shannan Professor Geoffrey West has received the Freedom of the City of London award. West was nominated by the Lord Mayor, Professor Michael Mainelli, for his work on scaling theory and its implications for the growth and dynamics of cities, companies, and the sustainability of the planet. West received the award at a ceremony in London’s Mansion House on October 28.

No matter how mundane or life-changing, the decisions we make are necessarily based on whatever limited information is available to us. If you’re weighing the risks of going outside during a pandemic, for example, you might base your decision on the news (which is updated only periodically) or whether you personally knew anybody who was sick (which is a small sample size.) SFI Complexity Postdoctoral Fellow Aanjaneya Kumar studies the science of making sound decisions based on limited information.