Networking the complexity community since 1999
Month: July 2023
Abnormal waves of electrical activity can cause a heart’s muscle cells to beat out of sync. In this episode, Flavio Fenton, an expert in cardiac dynamics, talks with Steve Strogatz about ways to treat heart arrhythmias without resorting to painful defibrillators.
Listen at: www.quantamagazine.org
Yiding Cao, Yingjun Dong, Minjun Kim, Neil G. MacLaren, Sriniwas Pandey, Shelley D. Dionne, Francis J. Yammarino, Hiroki Sayama
Human collectives, e.g., teams and organizations, increasingly require participation of members with diverse backgrounds working in networked social environments. However, little is known about how network structure and the diversity of member backgrounds would affect collective processes. Here we conducted three sets of human-subject experiments which involved 617 participants who collaborated anonymously in a collective ideation task on a custom-made online social network platform. We found that spatially clustered collectives with clustered background distribution tended to explore more diverse ideas than in other conditions, whereas collectives with random background distribution consistently generated ideas with the highest utility. We also found that higher network connectivity may improve individuals’ overall experience but may not improve the collective performance regarding idea generation, idea diversity, and final idea quality.
Read the full article at: arxiv.org
Complexity scientists have been able to make an impressive amount of progress despite the fact that there is not universal agreement about what “complexity” actually is. We know it when we see it, perhaps, but there are a number of aspects to the phenomenon, and different researchers will naturally focus on their favorites. Today’s guest, David Krakauer, is president of the Santa Fe Institute and a longtime researcher in complexity. He points the finger at the concept of agency. A ball rolling down a hill just mindlessly obeys equations of motion, but a complex system gathers information and uses it to adapt. We talk about what that means and how to think about the current state of complexity science.
Listen at: www.preposterousuniverse.com
Marc Barthelemy
Reports on Progress in Physics
Stochastic equations constitute a major ingredient in many branches of science, from physics to biology and engineering. Not surprisingly, they appear in many quantitative studies of complex systems. In particular, this type of equation is useful for understanding the dynamics of urban population. Empirically, the population of cities follows a seemingly universal law – called Zipf’s law – which was discovered about a century ago and states that when sorted in decreasing order, the population of a city varies as the inverse of its rank. Recent data however showed that this law is only approximate and in some cases not even verified. In addition, the ranks of cities follow a turbulent dynamics: some cities rise while other fall and disappear. Both these aspects – Zipf’s law (and deviations around it), and the turbulent dynamics of ranks – need to be explained by the same theoretical framework and it is natural to look for the equation that governs the evolution of urban populations. We will review here the main theoretical attempts based on stochastic equations to describe these empirical facts. We start with the simple Gibrat model that introduces random growth rates, and we will then discuss the Gabaix model that adds friction for allowing the existence of a stationary distribution. Concerning the dynamics of ranks, we will discuss a phenomenological stochastic equation that describes rank variations in many systems – including cities – and displays a noise-induced transition. We then illustrate the importance of exchanges between the constituents of the system with the diffusion with noise equation. We will explicit this in the case of cities where a stochastic equation for populations can be derived from first principles and confirms the crucial importance of inter-urban migrations shocks for explaining the statistics and the dynamics of the population of cities.
Read the full article at: iopscience.iop.org
As evidence of our global survival crisis continues to mount, the expression ‘too little, too late’ comes to mind. We all live in an interdependent world which has an increasingly shared fate. We are participants in an emerging global ‘superorganism’ that is dependent on close cooperation. Indeed, positive synergy (cooperative effects) has been the key to our evolutionary success as a species. However, our ultimate fate is now in jeopardy. Going forward, we must either create a more effective global society (with collective self-governance) or our species will very likely be convulsed by mass starvation, waves of desperate migrants, and lethal social conflict. The greatest threat we may face is each other, and a regression into tribalism and violent conflict. This Element has a more hopeful prescription for a new global social contract. It is based on the many examples of superorganisms – socially organized species – in the natural world, and in evolution.
More at: www.cambridge.org
Complexity Digest 