title: Explosive Contagion in Networks.
abstract: The spread of social phenomena such as behaviors, ideas or products is an ubiquitous but remarkably complex phenomenon. A successful avenue to study the spread of social phenomena relies on epidemic models by establishing analogies between the transmission of social phenomena and infectious diseases. Such models typically assume simple social interactions restricted to pairs of individuals; effects of the context are often neglected. Here we show that local synergistic effects associated with acquaintances of pairs of individuals can have striking consequences on the spread of social phenomena at large scales. The most interesting predictions are found for a scenario in which the contagion ability of a spreader decreases with the number of ignorant individuals surrounding the target ignorant. This mechanism mimics ubiquitous situations in which the willingness of individuals to adopt a new product depends not only on the intrinsic value of the product but also on whether his acquaintances will adopt this product or not. In these situations, we show that the typically smooth (second order) transitions towards large social contagion become explosive (first order). The proposed synergistic mechanisms therefore explain why ideas, rumours or products can suddenly and sometimes unexpectedly catch on.
authors.affiliation: Institute for Biocomputation and Physics of Complex Systems (BIFI), University of Zaragoza, Zaragoza, Spain.|Department of Condensed Matter Physics, University of Zaragoza, Zaragoza, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Gómez-Gardeñes
authors.affiliation: Departamento de Ciencias de la Computaci´on y de la Decisión, Universidad Nacional de Colombia, Medellín, Colombia.|Facultad de Ingeniería Industrial, Universidad Pontificia Bolivariana, Medellín, Colombia.
authors.forename: L
authors.initials: L
authors.lastname: Lotero
authors.affiliation: St. Catharine's College and Department of Chemistry, University of Cambridge, Cambridge, UK.
authors.forename: S N
authors.initials: SN
authors.lastname: Taraskin
authors.affiliation: Institute for Complex Systems and Mathematical Biology, SUPA, King's College, University of Aberdeen, Aberdeen, UK.
authors.forename: F J
authors.initials: FJ
authors.lastname: Pérez-Reche
mesh_terms: D006801:Humans; D007239:Infections / Q000453:epidemiology* / Q000635:transmission*; D008954:Models, Biological; D012919:Social Behavior; D012944:Social Support
references.citation: Science. 2009 Mar 13;323(5920):1453-5
references.pmid: 19286548
references.citation: Proc Natl Acad Sci U S A. 2002 Apr 30;99(9):5766-71
references.pmid: 16578874
references.citation: Phys Rev Lett. 2011 May 27;106(21):218701
references.pmid: 21699346
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2010 Sep;82(3 Pt 2):035101
references.pmid: 21230125
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2007 Dec;76(6 Pt 1):061904
references.pmid: 18233866
references.citation: Chaos. 2012 Mar;22(1):013101
references.pmid: 22462977
references.citation: Nature. 1964 Dec 12;204:1118
references.pmid: 14243408
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2014 May;89(5):052811
references.pmid: 25353848
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2009 Dec;80(6 Pt 1):061105
references.pmid: 20365116
references.citation: Sci Rep. 2015 Jul 07;5:11905
references.pmid: 26148542
references.citation: Phys Rev Lett. 2013 May 24;110(21):218701
references.pmid: 23745940
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2013 Dec;88(6):062815
references.pmid: 24483519
references.citation: Nature. 1964 Oct 17;204:225-8
references.pmid: 14212412
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2015 Jul;92(1):012820
references.pmid: 26274238
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2004 Aug;70(2 Pt 2):026114
references.pmid: 15447552
references.citation: Phys Rev Lett. 2012 Apr 20;108(16):168702
references.pmid: 22680761
references.citation: Phys Rev Lett. 2011 Mar 25;106(12):128701
references.pmid: 21517358
references.citation: Science. 2013 Mar 8;339(6124):1185-7
references.pmid: 23471402
references.citation: Chaos. 2014 Dec;24(4):043106
references.pmid: 25554026
references.citation: Phys Rev Lett. 2004 May 28;92(21):218701
references.pmid: 15245323
references.citation: Phys Rev Lett. 2006 May 26;96(20):208701
references.pmid: 16803215
references.citation: Phys Rev Lett. 2011 Jun 3;106(22):225701
references.pmid: 21702616
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2012 Jul;86(1 Pt 1):011128
references.pmid: 23005389
references.citation: Phys Rev Lett. 2010 Dec 17;105(25):255701
references.pmid: 21231601
references.citation: J Math Biol. 1987;25(4):359-80
references.pmid: 3668394