David Ropeik in The New York Times:
WE make all sorts of ostensibly conscious and seemingly rational choices when we are aware of a potential risk. We eat organic food, max out on multivitamins and quickly forswear some products (even whole technologies) at the slightest hint of danger. We carry guns and vote for the candidate we think will keep us safe. Yet these choices are far from carefully considered — and, surprisingly often, they contravene reason. What’s more, while our choices about risk invariably feel right when we make them, many of these decisions end up putting us in greater peril. Researchers in neuroscience, psychology, economics and other disciplines have made a range of discoveries about why human beings sometimes fear more than the evidence warrants, and sometimes less than the evidence warns. That science is worth reviewing at length. But one current issue offers a crash course in the most significant of these findings: the fear of vaccines, particularly vaccines for children. In a 2011 Thomson Reuters/NPR poll, nearly one parent in three with a child under 18 was worried about vaccines, and roughly one American in four was concerned about the value and safety of vaccines in general. In the same poll, roughly one out of every five college-educated respondents worried that childhood vaccination was connected with autism; 7 percent said they feared a link with Type 1 diabetes. Based on the evidence, these and most other concerns about vaccines are unfounded. A comprehensive report last year from the Institute of Medicine is just one of many studies to report that vaccines do not cause autism, diabetes, asthma or other major afflictions listed by the anti-vaccination movement. Yet these fears, fierce and visceral, persist. To frustrated doctors and health officials, vaccine-phobia seems an irrational denial of the facts that puts both the unvaccinated child and the community at greater risk (as herd immunity goes down, disease spread rises). But the more we learn about how risk perception works, the more understandable — if still quite dangerous — the fear of vaccines becomes.
Along with many others, the cognitive psychologists Paul Slovic of the University of Oregon and Baruch Fischhoff of Carnegie Mellon University have identified several reasons something might feel more or less scary than mere reason might suppose. Humans subconsciously weigh the risks and benefits of any choice or course of action — and if taking a particular action seems to afford little or no benefit, the risk automatically feels bigger. Vaccinations are a striking example. As the subconscious mind might view it, vaccines protect children from diseases like measles and pertussis, or whooping cough, that are no longer common, so the benefit to vaccination feels small — and smaller still, perhaps, compared to even the minuscule risk of a serious side effect. (In actuality, outbreaks of both of these infections have been more common in recent years, according to the Centers for Disease Control and Prevention.) Contrast this with how people felt in the 1950s, in the frightening days of polio, when parents lined their kids up for vaccines that carried much greater risk than do the modern ones. The risk felt smaller, because the benefit was abundantly clear.
More here.
