Bayesian Learning in Social Networks

http://pages.stern.nyu.edu/~ilobel/socialnetworks_revised.pdf

by wallflower • 16 years ago

49 4 16 years ago

pages.stern.nyu.edu

samd• 16 years ago

Can anyone translate the jargon into English? I tried to figure out what they were talking about, but their jargon is so impenetrable even Google struggles to provide meaning. It seemed to be something about how a Bayesian agent will inevitably reach the "right" decision given some type of social network...

snikolov• 16 years ago

I took a class on networks with Ozdaglar and Acemoglu and tried (unsuccessfully) to apply this paper to a more special case of networks whose interconnectivity is influenced by geometry (actual physical positions).

The short story is that this is a model of "herd" behavior, where observing enough (wrong) decisions by other before will make you choose the wrong thing as well, even if you know better. The next person after you will do the same, resulting in an "information cascade" of wrong decisions, even though everyone "knows better." The paper studies theoretical conditions for whether such information cascades happen or not.

The slightly longer story about these types of models is that you have a bunch of agents that decide A or B one after another. It is assumed that either A or B is "better." Each agent gets to see the decisions of some subset of the previous agents. Each agent also has their own belief. The agent will then make a decision based on observing the decisions of others (assuming something about their decision making process to try to estimate what might be the true answer).

The punchline is that even if your personal belief is biased toward the better answer, if enough people make the wrong decision by chance, everyone after them also will, despite knowing better, because it turns out to be optimal.

akshayubhat• 16 years ago

So many upvotes, I find information cascade happening here.

Bayesian Learning in Social Networks

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