title: Homophily and the speed of social mobilization: the effect of acquired and ascribed traits.
abstract: Large-scale mobilization of individuals across social networks is becoming increasingly prevalent in society. However, little is known about what affects the speed of social mobilization. Here we use a framed field experiment to identify and measure properties of individuals and their relationships that predict mobilization speed. We ran a global social mobilization contest and recorded personal traits of the participants and those they recruited. We studied the effects of ascribed traits (gender, age) and acquired traits (geography, and information source) on the speed of mobilization. We found that homophily, a preference for interacting with other individuals with similar traits, had a mixed role in social mobilization. Homophily was present for acquired traits, in which mobilization speed was faster when the recuiter and recruit had the same trait compared to different traits. In contrast, we did not find support for homophily for the ascribed traits. Instead, those traits had other, non-homophily effects: Females mobilized other females faster than males mobilized other males. Younger recruiters mobilized others faster, and older recruits mobilized slower. Recruits also mobilized faster when they first heard about the contest directly from the contest organization, and decreased in speed when hearing from less personal source types (e.g. family vs. media). These findings show that social mobilization includes dynamics that are unlike other, more passive forms of social activity propagation. These findings suggest relevant factors for engineering social mobilization tasks for increased speed.
authors.affiliation: Section on Critical Brain Dynamics, National Institute of Mental Health, Bethesda, Maryland, United States of America; Behavioral and Clinical Neuroscience Institute, Departments of Experimental Psychology and Psychiatry, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Jeff
authors.initials: J
authors.lastname: Alstott
authors.affiliation: Information Technologies Group, Sloan School of Management and Engineering Systems Division, School of Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America.
authors.forename: Stuart
authors.initials: S
authors.lastname: Madnick
authors.affiliation: Institute for Manufacturing, Department of Engineering, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Chander
authors.initials: C
authors.lastname: Velu
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D005260:Female; D033062:Friends / Q000523:psychology*; D006801:Humans; D033181:Information Dissemination; D007398:Interpersonal Relations; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012929:Psychological Distance; D012737:Sex Factors; D060756:Social Networking; D012944:Social Support; D013997:Time Factors
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