Cascading Into Serfdom
An interesting article in the New York Times today about the "Cascade Effect" on scientific consensus. Specifically, the article is dealing with the theory - pushed as stone-tablet fact for generations - that a high fat diet caused heart disease and a host of other problems. It turns out that the facts are quite different after the pseudo-science is stripped away.
In 1988, the surgeon general, C. Everett Koop, proclaimed ice cream to a be public-health menace right up there with cigarettes. Alluding to his office’s famous 1964 report on the perils of smoking, Dr. Koop announced that the American diet was a problem of “comparable” magnitude, chiefly because of the high-fat foods that were causing coronary heart disease and other deadly ailments.
He introduced his report with these words: “The depth of the science base underlying its findings is even more impressive than that for tobacco and health in 1964.”
That was a ludicrous statement, as Gary Taubes demonstrates in his new book meticulously debunking diet myths, “Good Calories, Bad Calories” (Knopf, 2007). The notion that fatty foods shorten your life began as a hypothesis based on dubious assumptions and data; when scientists tried to confirm it they failed repeatedly. The evidence against Häagen-Dazs was nothing like the evidence against Marlboros.
It may seem bizarre that a surgeon general could go so wrong. After all, wasn’t it his job to express the scientific consensus? But that was the problem. Dr. Koop was expressing the consensus. He, like the architects of the federal “food pyramid” telling Americans what to eat, went wrong by listening to everyone else. He was caught in what social scientists call a 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.
As the article goes on to explain, the "fat causes heart disease" meme is just not true. It is not confirmed by scientific tests. But that did not stop the media and the politicians from beating holy heck out of any expert who happened to point that out. Sound like something else that is going on today? I've been pointing things like this out for a while. Look at ulcers. For generations doctors recommended treating ulcers by drinking milk. That, of course, is actually one of the worst possible things you can do.
So how much cascade thinking is going on in scientific and political circles right now? Think global warming. Draconian solutions are all the rage. Crippling economies is touted as the way to go. Simply deciding to build a large number of nuclear power plants would solve the emissions concerns that so many people profess to have these days.
UPDATE: Sissy Willis has a good post up about this: "There are very few who can think, but every man wants to have an opinion"
Energy, Environment | Gaius Tuesday, 9 October , 2007
By feeblemind, Tuesday, 9 October , 2007 @ 9:16 pm
A remarkable article, considering the source.
By sam, Wednesday, 10 October , 2007 @ 12:43 pm
I agree that the cascade consensus explains a lot of the medical and nutritional misinformation that the public gets. One of my pet peeves is the “drink 8 glasses of water a day” meme that has no basis in medical research. The whole global warming hysteria also falls into this category in my opinion, as well as the “corn ethanol is evil” meme (sorry Gaius).
By Gaius, Wednesday, 10 October , 2007 @ 12:48 pm
Eh, I don’t think I called it evil. Just stupid as it is being implemented. But we can disagree over that.
By Sissy Willis, Wednesday, 10 October , 2007 @ 5:26 pm
Informational and reputational cascades emanating from elite institutions have always tried to drown out or shut out the voices of seekers of wisdom and truth:
There are very few who can think, but every man wants to have an opinion
By Gaius, Wednesday, 10 October , 2007 @ 5:42 pm
Nice job on that piece, Sissy.
By Sissy Willis, Thursday, 11 October , 2007 @ 4:30 am
Thanks, G, and thanks so much for linking! This topic is key to just about everything that gets my goat.