Informational Cascade

"We like to think that people improve their judgment by putting their minds together, and sometimes they do. The studio audience at “Who Wants to Be a Millionaire” usually votes for the right answer. But suppose, instead of the audience members voting silently in unison, they voted out loud one after another. And suppose the first person gets it wrong.

"If the second person isn’t sure of the answer, he’s liable to go along with the first person’s guess. By then, even if the third person suspects another answer is right, she’s more liable to go along just because she assumes the first two together know more than she does. Thus begins an “informational cascade” as one person after another assumes that the rest can’t all be wrong.

"Because of this effect, groups are surprisingly prone to reach mistaken conclusions even when most of the people started out knowing better, according to the economists Sushil Bikhchandani, David Hirshleifer and Ivo Welch. If, say, 60 percent of a group’s members have been given information pointing them to the right answer (while the rest have information pointing to the wrong answer), there is still about a one-in-three chance that the group will cascade to a mistaken consensus."

So says the New York Times!

I continually see informational cascades at work. Heck, I even start some of them.

I read a headline, presume the story behind it, and repeat what I presumed as if it related to the headline. I see someone behaving in some way that would mean something very specific if I were behaving in that way. (God and the person I see only know what their behavior really means!) I don't check in with them before concluding exactly what their behavior actually means, then pass my clever conclusion on just as if it were fact.

Fact is, I don't very often check my facts. I live on a diet of impressions, projections, and unsupportable conclusions. You probably do, too. My prejudices probably influence more of my conclusions than provable fact ever will --- or even could.

Ever had a piece you've written "fact checked?" It can be a disconcerting experience, as someone armed with encyclopedia and a LEXUS/NEXUS account tries to verify the truth of what you've written. In practice, the quality of the story seems more important than the absolute facts behind any story. Who could (or should) ever let the truth stand in the way of telling a compelling story?

To learn that scientists no less than any of the rest of us fall prey to informational cascades shouldn't surprise me. I spent about ten good, middle adult years, eating stuff that was supposed to lower my cholesterol but didn't.

We live, and apparently thrive on speculation. Always have. Always, I speculate, will. But then what do I really know? Our time here is little different than our ancestors' time here. Different speculations, but speculations none-the-less. We are confident that we know a lot, much of which isn't actually so.

Pass it on!

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