In the The Wisdom of Crowds, Surowiecki relates a couple of experiments illustrating the importance of diversity and independence in group decision making. In Solomon Asch's classic experiment, three individuals were asked say whether one of two lines on a sheet of paper was bigger, equally sized, or or smaller than another. The catch was, the first two respondents were plants, both of whom gave a clearly wrong answer. But in 70 percent of cases, the third respondent changed his answer, at least once, to match that of the group. Interviewed later, they hadn't thought their eyes were wrong, but they'd assumed safety in numbers. What added information, after all, did they possess that would leave them with a right answer while everyone else floundered? "Groupthink," writes Surowiecki, "works not so much by censoring dissent as by making dissent seem somehow improbable."
Later on, Surowiecki gives an example of an information cascade, in which a few visible individuals get bad information, or reach bad conclusions, in a public and early way. Assume two Chinese restaurants, one clearly better than the other, neither well-known to diners. If the first five dinner customers think they have reliable information that the worse restaurant is actually superior, they'll take their seats there. And if all the other diners see a little crowd in the worse restaurant and empty tables in the better establishment, they'll go into the worse restaurant. They'll assume, in other words, that the crowd is acting off good information, and they will be wrong.
Matt reminded me of this with his point that it wasn't that the experts who got the Iraq War wrong, but that "all the experts the Democratic Party leadership listened to were wrong [about Iraq]." We've had discussions over whether the progressive national security apparatus, the Democratic Party, the media, or some other force bears the brunt of the responsibility for convincing a sizable portion of Democrats to support the Iraq War. It's all of the above -- none are separable, as they all relied on the pressures and signals coming from one another.
A few hyper influential types -- Holbrooke, say, and Ken Pollack, and Tony Blair -- came to the wrong conclusion early on, and their decisions, based, as they supposedly were, on more and better information than the rest of us had, were enormously influential. Many who trusted them assumed, like with the early diners in the Chinese restaurant, that they must be in support for a reason, and so they fell in line. There's your information cascade. And once a critical mass of influentials were for the Iraq War, other influentials with more qualms either quieted their doubts or simply reversed them. It's hard to stand outside the group, particularly when you don't see where your information or expertise differ. If everyone else sees a small line, are you sure you're seeing a long one? And given that the pro-war perspective was broadly considered the safe political choice, and no one was going to get fired for saying what all the other consultants and advisors were saying (but they may well get fired for counseling opposition to a popular and successful war), the failures of our experts -- and thus, in cascade, our politicians, pundits, and many of ourselves -- look almost inevitable. No more excusable, but utterly predictable.
