APS fellowship to Stefano Boccaletti
ISC researcher Stefano Boccaletti has become APS fellows for seminal contributions to self-organization and control of continuous and distributed systems, including pattern formation in extended media and synchronization in networks and hypergraphs. Stefano Boccaletti is part of the Topical Group on Statistical and Nonlinear Physics and will give a Zoom seminar next Monday February 17th for the The klogW Series
Title: Why Are There Six Degrees of Separation in a Social Network?
Abstract
A wealth of evidence shows that real-world networks are endowed with the small-world property, i.e., that the maximal distance between any two of their nodes scales logarithmically rather than linearly with their size. In addition, most social networks are organized so that no individual is more than six connections apart from any other, an empirical regularity known as the six degrees of separation. Why social networks have this ultrasmall-world organization, whereby the graph’s diameter is even independent of the network size over several orders of magnitude, is still unknown. I will show that the “six degrees of separation” is in fact just the property featured by the equilibrium state of any network where individuals weigh between their aspiration to improve their centrality and the costs incurred in forming and maintaining connections. Moreover, the emergence of such a regularity is compatible with all other features, such as clustering and scale-freeness, that normally characterize the structure of social networks. Thus, simple evolutionary rules of the kind traditionally associated with human cooperation and altruism can also account for the emergence of one of the most intriguing attributes of complex networks.
