The “Majority Illusion” and other Paradoxes of Social Perception

Speaker: Kristina Lerman, Ph.D.
Affiliation: University of Southern California

Abstract: Individuals often estimate the opinions and behaviors of others from the local observations of their friends. Social networks, however, have counter-intuitive properties, which may significantly distort the observations people make of their friends. One of these properties is the “friendship paradox” that states that, on average, your friends have more friends than you do. Recently, a variety of other, stronger, paradoxes were demonstrated in social networks, including that most of your friends have more friends than you do. As a result of these paradoxes, an opinion that is globally rare in a network may be dramatically over-represented in the local neighborhoods of many individuals. This effect, which I call the “majority illusion,” leads individuals to systematically overestimate the prevalence of that opinion, and it may accelerate the spread of social contagions and adoption of social norms.

Biography: Kristina Lerman is a Project Leader at the University of Southern California Information Sciences Institute and holds a joint appointment as a Research Associate Professor in the USC Computer Science Department. Trained as a physicist, she now applies network- and machine learning-based methods to problems in social computing and social media analysis.

For more information, contact Prof. Mihaela van der Schaar (mihaelaucla@gmail.com)