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Common Sense
Surprising new research shows that crowds are often smarter than
individuals
By Michael Shermer
In 2002 I served as the "phone a friend" for the popular television series
Who Wants to Be a Millionaire. When my acquaintance was stumped by a question,
however, he elected to "poll the audience" instead. His choice was wise not
only because I did not know the answer but because the data show that the
audience is right 91 percent of the time, compared with only 65 percent for
"experts."
Although this difference may in part be because the audience is usually queried
for easier questions, something deeper is at work here. For solving a
surprisingly large and varied number of problems,
crowds are smarter
than individuals. This is contrary to what the 19th-century Scottish
journalist Charles Mackay concluded in his 1841 book, Extraordinary Popular
Delusions and the Madness of Crowds, a staple of skeptical literature:
"Men, it has been well said, think in herds. It will be seen that they go
mad in herds, while they only recover their senses slowly, and one by one."
This has been the dogma ever since, supported by sociologists such as Gustave
Le Bon, in his classic work The Crowd: A Study of the Popular Mind:
"In crowds it is stupidity and not mother wit that is accumulated."
Au contraire, Monsieur Le Bon. There is now overwhelming evidence, artfully
accumulated and articulated by New Yorker columnist James Surowiecki in his
enthralling 2004 book, The Wisdom of Crowds (Doubleday), that "the
many are smarter than the few." In one experiment, participants were asked
to estimate the number of jelly beans in a jar. The group average was 871,
only 2.5 percent off the actual figure of 850. Only one of the 56 subjects
was closer. The reason is that in a group, individual errors on either side
of the true figure cancel each other out.
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For a group to be smart, it should be autonomous, decentralized and
diverse.
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A similar result was discovered in an example so counterintuitive that it
startles. When the U.S. submarine Scorpion disappeared in May 1968,
a naval scientist named John Craven assembled a diverse group of submarine
experts, mathematicians and salvage divers. Instead of putting them in a
room to consult one another, he had each of them give a best guesstimate--based
on the sub's last known speed and position (and nothing else)--of the cause
of its demise and its rate and steepness of descent, among other variables.
Craven then computed a group average employing
Bayes Theorem, a
statistical method wherein a probability is assigned to each component of
a problem. The Scorpion's location on the ocean floor was only 220 yards
from the averaged prediction.
Stranger still was
the stock
market's reaction on January 28, 1986, the day the space shuttle Challenger
exploded. Of the four major shuttle contractors--Lockheed, Rockwell
International, Martin Marietta and Morton Thiokol--the last (the builder
of the defective solid-rocket booster) was hit hardest, with a 12 percent
loss, compared with only 3 percent for the others. A detailed study of the
market (a sizable crowd, indeed!) by economists Michael T. Maloney of Clemson
University and J. Harold Mulherin of Claremont McKenna College could find
no evidence of insider trading or media focus on the rocket booster or on
Morton Thiokol. Given four possibilities, the masses voted correctly.
Not all crowds are wise, of course--lynch mobs come to mind. And "herding"
can be a problem when the members of a group think uniformly in the wrong
direction. The stock market erred after the space shuttle Columbia disaster
on February 1, 2003, for example, dumping stock in the booster's manufacturer
even though the boosters were not involved.
For a group to be smart, it should be autonomous, decentralized and cognitively
diverse, which the committee that rejected the foam-impact theory of the
space shuttle Columbia while it was still in flight was not. In comparison,
Google is brilliant because it uses
an algorithm that ranks Web pages by the number of links to them, with those
links themselves valued by the number of links to their page of origin. This
system works because the Internet is the largest autonomous, decentralized
and diverse crowd in history, IMHO.
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Michael Shermer is publisher of Skeptic (www.skeptic.com) and author of
The Science of Good and Evil.
MORE SKEPTIC:
Turn Me On, Dead Man
The Feynman-Tufte Principle
The Fossil Fallacy
Abducted!
Quantum Quackery
Skeptic.com
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