nos-trum. pronunciation: \nos'-trum\. noun. Etymology: Latin, neuter of noster our, ours.
1. a medicine of secret composition recommended by its preparer but usually without scientific proof of its effectiveness.
2. a usually questionable remedy or scheme.
See here for more discussion.

Monday, March 14, 2011

Why People Disbelieve The Science...Often Strongly So.

Beliefs about issues like vaccination are driven by cultural values not scientific evidence.

Such is the theory of risk proposed by researchers like Dan M. Kahan, of Yale Law School, who has written on the conflict that develops when all the scientific experts agree but some members of the public do not (and vehemently so).

This came up in an article in the Wall Street Journal Health Blog two days ago (Mar 12).  The original article concerned the "clash" between patients and scientists over a suspected viral cause for chronic fatigue syndrome (CFS).  Almost everyone has heard of CFS:  a debilitating and chronic syndrome, the etiology for which doctors and scientists have been speculating and experimenting for decades.  The literature, advocacy groups, and blogs are littered with ideas, allegations, hypotheses, and claims.

Desperate for a cause and a treatment, patients have alleged conspiracies to cover up evidence that the syndrome is a definable disease with a specific cause, and at the same time have suffered the ignominy of disbelief and disparagement by the public...and sometimes, doctors.

Along the way, quacks with remedies and healthy people who want to jump on the bandwagon to explain their life stress have muddied the waters and confused patients and public alike.

Desperate people are the most vulnerable to quackery.

The fact that XMRV--the suspected virus--has only been associated with CFS in one or two small studies, but other investigators have not been able to reproduce those results, drives the desperate to want an answer NOW.  Scientists, knowing that initial studies are often a red herring, want to be deliberate and systematic.

See the blog for more detail on CFS.  At one point the article branches off into why people sometimes strongly disbelieve the empirical data (as in the autism-vaccine debacle).  One theory, and a good one to explore, is that people develop belief that accords with their values over the evidence.  From one of Kahan's papers (on the controversy over requiring adolescents to take the Human Papilloma Virus--HPV--vaccine) found here (on SSRN):
"The cultural theory of risk asserts that individuals selectively attend to risks and related facts in a way that reflects and reinforces their "cultural worldviews," or preferences about how society should be organized (citations).  If this process is at work in the HPV vaccine debate, those on both sides are advancing the positions that they honestly believe promote the health of girls and young women. Yet the reason that they hold those particular beliefs is the congeniality of one or another set of risk perceptions to their preferred vision of the good society."

The science is clear that HPV vaccine is safe and effective against several strains of the virus that can lead to cervical cancer, that HPV infection is spread as an STD, and that the vaccine can interrupt the chain of transmission in many cases.

Kahan relates the HPV story to other controversies such as gun control, and links the resulting conflicts to the cultural theory of risk.

Both the blog article and the paper referenced are recommended reading.

Doc D

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