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This presentation delves into the concepts of social influence and correlation within social networks, exploring their distinct yet interrelated nature. It examines how individuals interact, share advice, and the various driving factors behind social behavior. Through experimental evaluations, including influence and correlation models, we assess the dynamics of social connections and the effects of homophily and confounding factors. The future direction includes investigating stable relationships in online communities and their evolution over time, revealing deeper insights into social network interactions.
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Influence and Correlation in Social Networks Xufeiwang Nov-7-2008
Outline • Background, Concepts • Problem statement • Basic idea • Experimental Evaluation • Future directions
Proofs of social correlation • People interact with others • Advices, reading, commenting • Communicating with others • Non-causal correlation • Both the CO2 level and crime level have increased sharply • Both beer and diaper sales well in a super market • Causal correlation • I bought an IPhone after I’m recommended by my friend
Social influence • A bought an IPhoneafter B told him it’s cool • Directed: B influences A, not A influences B • Chronological: A is influenced after B told him • Asymmetry: B has influence to A doesn’t imply A has the same influence to B
Sources of correlation • Socialinfluence: One person performing an action can cause her contacts to do the same. • A bought an IPhoneafter B told him it’s cool • Homophily: Similar individuals are more likely to become friends. • Example: two mathematicians are more likely to become friends. • Confoundingfactors: External influence from elements in the environment. • Example: friends live in the same area, thus attend and take pictures of similar events, and tag them with similar tags.
Outline • Background, Concepts • Problem statement • Basic idea • Experimental Evaluation • Future directions
Problem statement • Social correlation and social influence are different concepts • Are they related? • Maybe yes and Maybe no
Outline • Background, Concepts • Problem statement • Basic idea • Experimental Evaluation • Future directions
Social correlation evaluation • Influence model: each agent becomes active in each time step independently with probability p(a), where a is the # of active friends. • Natural choice for p(a): logistic regression function: with ln(a+1) as the explanatory variable. I.e., • Coefficient α measures social correlation.
Testing for influence • Shuffle Test: • Chronological property • Edge-Reversal Test: • Asymmetry property C C A A B B
Outline • Background, Concepts • Problem statement • Basic idea • Experimental Evaluation • Future directions
Experimental setup • Influence model • Only use the influence factor • Current node A has “a” active friends, its probability to be active is related with the # of active friends • Correlation model • Use the homophily and confounding factors • Init S nodes as centers randomly, add a ball of radius 2 to each node in S, according to the data on Flickr, randomly pick the same # of nodes to be active
Explanations • The users’ tagging actions are independent • The users either seldom visit their friends’ pages • Or the users visit pages but only care about the content rather than the tags
Outline • Background, Concepts • Problem statement • Basic idea • Experimental Evaluation • Future directions
Future directions I • The relationship in the internet is weak! • How weak it is? • So I think it’s interesting to search close communities, based on strong correlation, in blogosphere • How to define the “strongness” • How the “strongness” among the users • Do we have reasonable datasets • “strongness” is related with time?
Future Directions II • Most of the users don’t contact frequently • How about the contact distribution • Search for stable relationships is also interesting. Seeking stable communities • How to define stable? • Stable relationship can be strong or weak connection • Contact infrequently but regularly • The group can be small • Hold for a long time??