Damon Centola, University of Pennsylvania

Abstract

Despite decades of work on the network structures underlying social influence, standard measures of node centrality frequently misidentify the most influential nodes in a network. Meanwhile, these standard measures continue to be widely employed in policy-relevant domains, from marketing to public health, for the purpose of identifying influential “seed” nodes for initiating the spread of behavior. In this work, we identify a key assumption in prior network-based measures of node centrality and social distance that significantly limit their capacity to characterize social influence. Standard measures of node centrality often assume a “simple” model of contagion, in which individuals only require exposure to one activated peer to adopt. Yet, many social contagions are “complex,” for which people require exposure to multiple activated peers. In this study, we provide novel topological measures of i) “complex path length” (which replaces the classic measure of “simple path length”), and ii) “complex centrality” (which replaces all standard measures of network centrality) to identify seeding locations that maximize the spread of social contagions across complex networks. We test our predictions empirically by applying the theory of complex centrality to identify optimal seeding strategies for a microfinance program in India, and experimentally evaluating the best seeding practices for initiating the spread new farming practices in Malawi.

Speaker Bio:

Damon Centola is the Elihu Katz Professor of Communication, Engineering and Sociology at the University of Pennsylvania where he is Director of the Network Dynamics Group and a Senior Fellow at the Leonard Davis Institute of Health Economics. Before coming to Penn, Damon was a Robert Wood Johnson Fellow at Harvard University, and a Professor of System Dynamics at MIT. Damon is one of the world’s leading scholars on social networks and behavior change. His work has received numerous awards including the Goodman Prize for Outstanding Contribution to Sociological Methodology in 2011; the James Coleman Award for Outstanding Research in Rationality and Society in 2017; and the Harrison White Award for Outstanding Scholarly Book in 2019. He was a developer of the NetLogo agent based modeling environment, and was awarded a U.S. Patent for inventing a method to promote diffusion in online networks. He is a member of the Sci Foo community and Fellow of the Center for Advanced Study in the Behavioral Sciences at Stanford University. His work has been funded by the National Science Foundation, the Robert Wood Johnson Foundation, Facebook, the National Institutes of Health, the James S. McDonnell Foundation, and the Hewlett Foundation. Popular accounts of Damon’s work have appeared in The New York Times, The Washington Post, The Wall Street Journal, Wired, TIME, The Atlantic, Scientific American and CNN, among other outlets. His speaking and consulting clients include Amazon, Microsoft, Apple, Google, Cigna, the Smithsonian Institution, the American Heart Association, Moore Foundation, General Motors, the National Academies, DOD, US State Department, U.S. Army and the NBA, among others. He is a series editor for Princeton University Press, and the author of How Behavior Spreads: The Science of Complex Contagions (Princeton, 2018), and Change: How to Make Big Things Happen (Little Brown, 2021).