October 10, 2011


What You Don't Know Can Kill You: Humans have a perplexing 
tendency to fear rare threats such as shark attacks while blithely 
ignoring far greater risks like 
unsafe sex and an unhealthy diet. Those illusions are not just 
silly--they make the world a more dangerous place.
 (Jason Daley, 10.03.2011, Discover Magazine)

Last march, as the world watched the aftermath of the Japanese earthquake/tsunami/nuclear near-meltdown, a curious thing began happening in West Coast pharmacies. Bottles of potassium iodide pills used to treat certain thyroid conditions were flying off the shelves, creating a run on an otherwise obscure nutritional supplement. Online, prices jumped from $10 a bottle to upwards of $200. Some residents in California, unable to get the iodide pills, began bingeing on seaweed, which is known to have high iodine levels.

The Fukushima disaster was practically an infomercial for iodide therapy. The chemical is administered after nuclear exposure because it helps protect the thyroid from radioactive iodine, one of the most dangerous elements of nuclear fallout. Typically, iodide treatment is recommended for residents within a 10-mile radius of a radiation leak. But people in the United States who were popping pills were at least 5,000 miles away from the Japanese reactors. Experts at the Environmental Protection Agency estimated that the dose of radiation that reached the western United States was equivalent to 1/100,000 the exposure one would get from a round-trip international flight.

Although spending $200 on iodide pills for an almost nonexistent threat seems ridiculous (and could even be harmful--side effects include skin rashes, nausea, and possible allergic reactions), 40 years of research into the way people perceive risk shows that it is par for the course. Earthquakes? Tsunamis? Those things seem inevitable, accepted as acts of God. But an invisible, man-made threat associated with Godzilla and three-eyed fish? Now that's something to keep you up at night. "There's a lot of emotion that comes from the radiation in Japan," says cognitive psychologist Paul Slovic, an expert on decision making and risk assessment at the University of Oregon. "Even though the earthquake and tsunami took all the lives, all of our attention was focused on the radiation."

We like to think that humans are supremely logical, making decisions on the basis of hard data and not on whim. For a good part of the 19th and 20th centuries, economists and social scientists assumed this was true too. The public, they believed, would make rational decisions if only it had the right pie chart or statistical table. But in the late 1960s and early 1970s, that vision of homo economicus--a person who acts in his or her best interest when given accurate information--was knee­capped by researchers investigating the emerging field of risk perception. What they found, and what they have continued teasing out since the early 1970s, is that humans have a hell of a time accurately gauging risk. Not only do we have two different systems--logic and instinct, or the head and the gut--that sometimes give us conflicting advice, but we are also at the mercy of deep-seated emotional associations and mental shortcuts. [...]

[W]e focus on the one-in-a-million bogeyman while virtually ignoring the true risks that inhabit our world. News coverage of a shark attack can clear beaches all over the country, even though sharks kill a grand total of about one American annually, on average. That is less than the death count from cattle, which gore or stomp 20 Americans per year. Drowning, on the other hand, takes 3,400 lives a year, without a single frenzied call for mandatory life vests to stop the carnage. A whole industry has boomed around conquering the fear of flying, but while we down beta-blockers in coach, praying not to be one of the 48 average annual airline casualties, we typically give little thought to driving to the grocery store, even though there are more than 30,000 automobile fatalities each year.

In short, our risk perception is often at direct odds with reality. All those people bidding up the cost of iodide? They would have been better off spending $10 on a radon testing kit. The colorless, odorless, radioactive gas, which forms as a by-product of natural uranium decay in rocks, builds up in homes, causing lung cancer. According to the Environmental Protection Agency, radon exposure kills 21,000 Americans annually.

David Ropeik, a consultant in risk communication and the author of How Risky Is It, Really? Why Our Fears Don't Always Match the Facts, has dubbed this disconnect the perception gap. "Even perfect information perfectly provided that addresses people's concerns will not convince everyone that vaccines don't cause autism, or that global warming is real, or that fluoride in the drinking water is not a Commie plot," he says. "Risk communication can't totally close the perception gap, the difference between our fears and the facts."

Posted by at October 10, 2011 6:25 PM

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