Hierarchical Block Structures and High-Resolution Model Selection in Large Networks

Many social, technological, and biological networks are composed of modules, representing groups of nodes that are assumed to have a similar role in the functioning of the network. The use of statistical generative models that formally characterize this modular structure is a powerful tool that allows...

The Neural Dynamics of Decision Making: Multiple Scales and a Range of Models

I describe a range of models, from cellular to cortical scales, that illuminate how we accumulate evidence and make simple decisions. Large networks composed of individual spiking neurons can capture biophysical details of synaptic transmission and neuromodulation, but their complexity renders them opaque...

From Scaling to Practice: Real World Applications of Cities Research

Annual Science Board Symposium and Meeting Complexity: Theory and Practice

Large-Scale Structure in Networks

Annual Science Board Symposium and Meeting Complexity: Theory and Practice

The Conceptual Framework of Urban Scaling

Annual Science Board Symposium and Meeting Complexity: Theory and Practice

Brief Research Talks - Omidyar Postdoctoral Fellows

Annual Science Board Symposium and Meeting Complexity: Theory and Practice

Physics-Inspired Algorithms and Phase Transitions in Community Detection

Annual Science Board Symposium and Meeting Complexity: Theory and Practice

Pathogen Diversity from an Ecological Perspective

Annual Science Board Symposium and Meeting Complexity: Theory and Practice

Better Forecasting Our Ecological Future: Taming Big Data with Big Theory

Annual Science Board Symposium and Meeting Complexity: Theory and Practice

Welcome to the 2014 SFI Science Board Symposium

Annual Science Board Symposium and Meeting Complexity: Theory and Practice

Polyplexity: Complexity Science for the Social and Policy Sciences

Herbert Simon’s famous ant-on-the-beach metaphor points to the possibility of two alternative representations for the same complex phenomenon: the ant’s convoluted path on the beach may be described as complex behavior against a simple background, or as simple behavior against a complex background. Taking...

What's Science News (and What Isn't)?

SFI journalism fellow Guy Gugliotta talks about what makes a science news story, how reporters choose what they write, and how science reporters interact with scientists — what reporters need, what they get, how reporters and scientists misunderstand each other, and how the process might be streamlined...

Sandpiles and System-Spanning Avalanches

A sandpile on a graph is an integer-valued function on the vertices. It evolves according to local moves called topplings. Some sandpiles stabilize after a finite number of topplings, while others topple forever. For any sandpile s_0 if we repeatedly add a grain of sand at an independent random vertex,...

Denaturation of Circular DNA

DNA denaturation is the process by which the two strands of a DNA molecule separate. This process is essential both for biological processes such as gene transcription and for artificial processes such as PCR. A prototypical model for studying the denaturation of DNA upon heating is the Poland-Scheraga...

The Emergence of Organizations and Markets

The social sciences have sophisticated models of choice and equilibrium but little understanding of the emergence of novelty. Where do new alternatives, new organizational forms, and new types of people come from? Combining biochemical insights about the origin of life with innovative and historically...

Informational Principles in the Perception-Action Loop

Ashby's Law of Requisite Variety (1956) and, in last years, especially its later rediscovery and extension by Touchette and Lloyd (2000, 2004) have indicated that Shannon information acts as fundamental "currency" constraining the potential organization and "administration" of cognitive tasks. In particular,...

Why the Internet Won't Get You Any More Friends

Social media promises us an ever-expanding circle of friends, but that may be an empty promise. Social behavior is firmly rooted in biology, and our brains are hard-wired to maintain meaningful relationships with only about 150 people. Evolutionary psychologist Robin Dunbar formulated "Dunbar's Number"...

What’'s So Social About the Social Brain?

The social brain hypothesis was formally launched two decades ago, and the intervening period has seen a considerable amount of both comparative and neuroimaging research. While evidence in support of the quantitative predictions of the hypothesis has accumulated steadily, it has also become apparent...

Medical, Scientific, Political and Journalistic Pitfalls in the Study of Confusing Illnesses

When illnesses are confusing, without clear mechanisms or sharply-defined symptoms, they are often considered psychosomatic, and there's a consistent pattern of poor handling by federal agencies, researchers, doctors, and the media. AIDS, multiple sclerosis, chronic Lyme disease, and chronic fatigue...

A Game Approach to the Emergence of Hostile Leadership

Recent archaeological models have examined consensual paths to incipient social leadership. A modification of the Hawk-Dove game explores conditions under which non-consensual appropriation of resources is rewarded. In some circumstances such behavior is not rewarded even in the absence of sanctions....