What Is A Network and why do we

What Is A Network? (and why do we care? )

Recap: Network Defined “A collection of objects (nodes) connected to each other in some fashion” - Watts, 2002 An Introduction to Network Theory | Kyle Findlay | SAMRA 2010 | 2

Recap: In A Network … are affected by the actions of others around it. • An agent/object's actions made in isolation, i. e. , they are contingent • Actions/choices are not on the actions and choices of others An Introduction to Network Theory | Kyle Findlay | SAMRA 2010 | 3

Recap: Terms • Node = individual components of a network, e. g. people, power stations, links • Edge = direct link between components (referred to as a dyad in context of social networks, a relationship between two people) • Path = route taken to connect two nodes. “Six degrees of separation” average path length = 6

Recap: Power Law

Recap: CA F 500 Companies http: //flickr. com/photos/11242012@N 07/1363558436

Two New Concepts • Dunbar Number • Tipping Point An Introduction to Network Theory | Kyle Findlay | SAMRA 2010 | 7

Dunbar Number • Dunbar, an anthropologist at the University College of London, studied primates. . there is a cognitive limit to the number of individuals with whom any one person can maintain stable relationships… • • … this limit is a direct function of relative neocortex size, and that this in turn limits group size … … language evolved as a "cheap" form of social grooming … •

Dunbar Number • Off-line (real world) networks • Estimate: 150 (average) • Does it apply to online digital networks? It is the mean when a group is “highly incentivized to remain together” • An Introduction to Network Theory | Kyle Findlay | SAMRA 2010 | 9

Dunbar Number danah boyd: [Dunbar] found that the MAXIMUM number of people that a person could keep up with socially at any given time, gossip maintenance, was 150. This doesn't mean that people don't have 150 people in their social network, but that they only keep tabs on 150 people max at any given point. •

Dunbar Number … …. versus optimal group size • Anecdotal: appears to be 5 -9 members • Mythical Man Month How a software project manager would schedule timeline for a baby (it’s a joke!) • An Introduction to Network Theory | Kyle Findlay | SAMRA 2010 | 11

Dunbar Number … … and Facebook and Twitter is example of a directed social network (lack of reciprocity) • Facebook (fully connected network) requires reciprocity • Neither concept measures conversation as “connection” • An Introduction to Network Theory | Kyle Findlay | SAMRA 2010 | 12

Tipping Points • Popularized by Malcolm Gladwell Term comes from epidemiology – the moment in an epidemic when a virus reaches critical mass. • Critical mass comes from nuclear physics – “any mass that, when exceeded, causes something to happen” • An Introduction to Network Theory | Kyle Findlay | SAMRA 2010 | 13

Tipping Points The point in adoption cycle when “everyone has to have <it>” • • Applies to ideas, products, “viral videos” "Will You. Tube be the tipping point for livestreaming? ” • An Introduction to Network Theory | Kyle Findlay | SAMRA 2010 | 14

Tipping Points Discontinuous change - Gladwell: “Things can happen all at once, and little changes can make a huge difference. ” • Law of the Few (idea needs endorsement by connectors, mavens and salesmen) • Stickiness Factor (what makes us pay close attention to something) • • Power of Context An Introduction to Network Theory | Kyle Findlay | SAMRA 2010 | 15

Facebook Visualization Be sure to deauthorize these apps after testing! • • Facebook Visualizer • Friend Wheel • Like. Button Visualizer An Introduction to Network Theory | Kyle Findlay | SAMRA 2010 | 16

Credits • Kathy E Gill, @kegill, CC share-alike, non-commercial