In this article, http://www.worldchanging.com/archives/005507.html, Ethan Zuckerman offers bloggers an overview and a review of Cass Sunstein’s book, Infotopia: How Many Minds Produce Knowledge.  The review is fairly long and covers a large amount of information and Sunstein’s argument about how today’s society aggregates information—for better of worse.  While I cannot cover all of Sunstein’s points, I recommend that you browse through the review to read about the author’s full argument, which incorporates interesting ideas from Hayek’s theory of market aggregation and Habem’s ideas about deliberative groups to prediction markets and open source software.  Zuckerman’s analysis of Sunstein’s argument reveals some of the holes and lingering questions in Infotopia.

One of Sunstein’s most interesting conclusions reflects back to what we’ve learned this week about information cascades.  Sunstein looks into group decision making through the Condorcet Jury Theorem.  The Theorem states that if individual jury members each have a probability of making the correct decision on the verdict that is greater than half (.5), then together, as a full jury, they will have an even better probability of choosing the correct verdict.  But, if the individual probabilities are less than one-half, they combined probability for a correct decision will be even worse.  This jury shares some qualities with an information cascade, if we translate making the correct decision to having a good outcome, as we did in class.  There is a parallel of p(G/H) > p, since Condorcet suggests that p(Choosing right verdict given signals from others) is greater that p, or the individual probability of choosing the right verdict. 

To fix that negative trend of higher probability of a wrong verdict, Sunstein proposes group deliberation as a way to break a cascade in the wrong direction.  Yet, citing his own study that used politically-oriented focus groups in Colorado, deliberation in a group setting often fails to secure the “right” outcome.  Sunstein suggests that deliberation fails for three reasons.  Firstly, individuals in groups support the opinion that is relayed with the most confidence.  An impassioned juror who speaks first can cause a cascade, as we have learned from class.  Also, if you consider the information gleamed from the media during the trial as a sort of better information, an individual member who has this information, as a “fashion leader,” can throw off the cascading jury vote, for better or worse.  The fragility of this cascade demonstrates the importance of isolating jurors during high profile trials.  A second factor limiting deliberation is that individuals in like-minded groups repeat evidence that further supports that dominant opinion and shut out minor opinions.  This “preaching to the choir” trend makes it less likely for a minority opinion, even if it is the correct one, to be heard.  Thirdly, individuals who support the minority opinion, which in this case is the “right” one, tend to avoid conflict and do not speak up in group settings.  In reasons two and three, Sunstein argues that cascades are not as fragile as previously believed.  He suggests that it is rather difficult to change the course of a cascade through group deliberation unless an individual presents the most “strongly-stated opinion.”  By building this argument, Sunstein seems to urge individuals with the “right” opinion to assert themselves in group situations in order to effectively steer the group’s cascading decision-making process.