“Connected” At Last

Networked LifeCIS 112

Spring 2010Prof. Michael Kearns

What’s Different?

• Backgrounds of Christakis and Fowler– practicing medical and social health researchers– more likely to conduct survey studies, examine social interactions in detail

• Compared to “The Tipping Point”– considerably less anecdotal– almost all claims backed up by scientific studies

• Compared to “Six Degrees”– almost entirely empirical– field studies of social networks and contagion vs. math models and data

analysis• Detailed tracking of influence and contagion

– in the physical world, not online/virtual– details of individuals in the social network– tracked over many years/decades– much of it based on the Framingham Heart Study data– contagion: from metaphor to mechanism

Christakis and Fowler “Rules”

• We shape our network– deliberate structuring/restructuring of our social NWs– contrast with “passive” network formation models considered so far– later: “economic” network formation models --- closer to C+F, but…

• Network shapes us– declining IQ of later-born children and network structure– divorce as a devastating reduction of clustering coefficient (0.52 in USA)

• Emergent behavior in networks– “Social networks can have properties and functions that are neither

controlled nor even perceived by the people within them.”– flocking/schooling, stadium waves, standing ovations,…– much more coming in “Micromotives and Macrobehavior”

• Three degrees of influence– a claim about dynamics of influence, vs. static structure (6 degs of

separation)– applies to word-of-mouth recommendations, weight gain, ideas,

happiness…

Emotional Contagion• Highly localized: “laughter epidemic” in Tanzania 1962• Evolutionary benefits of emotion contagion

– herding behavior, protection from predators; contagion of courage– maternal protection– may predate, and be faster than, oral communication

• Case studies of Mass Psychogenic Illness (MPI)– perhaps easiest to identify and study– Tennessee 1998: phantom fume epidemic; contagion of anxiety– NYC 1990: Triborough Bridge “sweetness” epidemic– Now: “nut free” schools?

• What about more diffuse contagion?

Moods, Health and Habits• Let’s look at the Christakis-Fowler papers on:

– contagion of happiness– contagion of loneliness– contagion of obesity– contagion of smoking (cessation)