The New York Times has this article on fatty foods and the concept of “informational cascade.”
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.
Does this sound like another religious “scientific” non-debate grabbing headlines recently? In fact, let’s play a game. I’ll just take some of the money lines from this article on the health effects of fat and substitute a few words.
– “The scientists, despite their impressive credentials, were accused of bias because some of them had done research financed by the food [oil] industry.”
– “With skeptical scientists ostracized, the public debate and research agenda became dominated by the fat-is-bad [catastrophic global warming] school.”
– “Later the National Institutes of Health [Intergovernmental Panel on Climate Change] would hold a “consensus conference” that concluded there was “no doubt” that low-fat diets “will afford significant protection against coronary heart disease” for every American over the age of 2 [global warming is now a reality].”
– “But when the theories were tested in clinical trials [against actual climate data], the evidence kept turning up negative.”
On both global warming and dietary fat, I’ll defer to the wisdom of Dr. Edward H. Ahrens Jr., who stood steadfast against the fat-is-bad consensus:
“This is a matter,” he continued, “of such enormous social, economic and medical importance that it must be evaluated with our eyes completely open. Thus I would hate to see this issue settled by anything that smacks of a Gallup poll.”